一、開始啟程
Log的快捷方式：logd/logt等等

二、探究活動
1.使用Menu
建立menu文件夾，新建一個叫main的菜單文件：

 <item
        android:id="@+id/add_item"
        android:title="Add" />
    <item
        android:id="@+id/remove_item"
        android:title="Remove" />

在FirstActivity中重寫onCreateOptionsMenu()和onCreateOptionsMenu()方法：

    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main,menu);
        return true;
    }
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.add_item:
                break;
            case R.id.remove_item:
                break;
            default:
        }
        return true;
    }

銷毀一個活動：finish();

2、使用Intent在活動之間穿梭
啟動另一個活動：

Intent intent = new Intent(FirstActivity.this,SecondActivity.class);
startActivity(intent);

隱式：
在manifest文件中sencondacitvity標簽添加如下：

<intent-filter>
    <action android:name="com.lewanjiang.activitytest.ACTION_START"/>
    <category android:name="android.intent.category.DEFAULT" />
</intent-filter>

 Intent intent = new Intent("com.lewanjiang.activitytest.ACTION_START");
startActivity(intent);

同時可添加category。:

int1.addCategory("com.lewanjiang.activitytest.MY_CATEGORY");

添加后不要忘記在manifest文件中聲明category。

Intent更多用法：打開網址和撥打電話

Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://bing.com"));
startActivity(intent);
Intent intent1 = new Intent(Intent.ACTION_DIAL);
intent1.setData(Uri.parse("tel:10088"));
startActivity(intent1);

響應打開網頁：在manifest的activity的<intent-filter>中：

<actioni android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="http" />

向下一個活動中傳遞數據：
方法一：
第一個活動中：

String data = "hello bob";
Intent intent = new Intent(MainActivity.this,SecondActivity.class);
intent.putExtra("tran",data);
startActivity(intent);

第二個活動中：

Intent intent = getIntent();
String data = intent.getStringExtra("tran");

常用寫法：
第一個活動中：

SecondActivity.actionStart(FirstActivity.this,"dat1","dat2");

第二個活動中：

public static void actionStart(Context context,String data1,String data2) {
    Intent int1 = new Intent(context,SecondActivity.class);
    int1.putExtra("par1",data1);
    int1.putExtra("par2",data2);
    context.startActivity(int1);
}

返回數據給第一個活動：
第一個活動中：

Intent int1 = new Intent(FirstActivity.this,SecondActivity.class);
startActivityForResult(int1,1);
@Overrid
protected void onActivityResult(int reqCod,int resCod,Intent data){
    switch (reqCod) {
        case 1:
            if (resCod == RESULT_OK) {
                String retDat = data.getStringExtra("tran");
                Log.d("FirstActivity", retDat);
            }
            break;
        default:
    }
}

第二個活動中：

Intent int1 = new Intent();
int1.putExtra("tran","Hello bob again");
setResult(RESULT_OK,int1);

響應返回鍵時，可將以上代碼寫在onBackPredded()中。

典型生命周期：onCreate、onStart（前臺）、onResume（可見）、onPause、onStop、onDestroy、onRestart

        if (savedInstanceState != null) {
            String test = savedInstanceState.getString("extra_test");
            Log.d(TAG,"[onCteate]restore extra_test:" + test);

    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        Log.d(TAG,"onSaveInstanceState");
        outState.putString("extra_test","haha");
    }

    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        String test = savedInstanceState.getString("extra_test");
        Log.d(TAG,"[onRestoreInstanceState]restore extra_test" + test);
    }

內存不足Activity被殺死時與被銷毀時一致
避免Activity被重新創建：設置android:configChanges屬性

啟動模式：standard/singleTop/singleTask/singleInstance 在manifest文件中修改：android:launchMode="singleTask"

Flags:
常用Flags:FLAG_ACTIVITY_NEW_TASK、FLAG_ACTIVITY_SINGLE_TOP、FLAG_ACTIVITY_CLEAR_TOP、FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS

找到當前活動和退出所有活動：

public class BaseActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityCollector.addActivity(this);
        Log.d("BaseActivity",getClass().getSimpleName());
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
    }
}
public class ActivityCollector {
    public static List<Activity> acts = new ArrayList<>();
    public static void addActivity(Activity act) {
        acts.add(act);
    }
    public static void removeActivity(Activity act) {
        acts.remove(act);
    }
    public static void finishAll() {
        for (Activity act:acts) {
            if (!act.isFinishing()) {
                act.finish();
            }
        }
    }
}

三、UI開發
基本控件與布局
android:gravity、android:textSize、android:textColor、android:textAllCaps、android:layout_gravity、android:hint、android:maxLines
textView屬性：
點擊；android:clickable="true"

Button:
android:textAllCaps
implement View.OnClickListener
public void onClick(View v){ switch(v.getid()){ case: ...} }

EditText:
android:hint、android:maxLines
String inpTex=editText().getText().toString();

ImageView:
android:src
imaVie.setImageResource(R.drawable.hah);

ProgressBar:
style="?android:attr/progressBarStyleHorizontal"
android:max

if(prBar.getVisibility() == View.GONE)
proBar.setVisibility(View.VISIBLE);
int prooo=proBar.getProgress();
proBar.setProgress(666);

AlertDialog:

AlertDialog.Builder dia = new AlertDialog.Builder(MainActivity.this);
dia.setTitle("TITLE");
dia.setMessage("hahahahaha");
dia.setCancelable(true);
dia.setPositiveButton("OK", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int which) {
        Log.d("MainActivity","haha");
    }
});
dia.setNegativeButton("Cancle", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialog, int which) {
        Log.d("MainActivity","heihei");
    }
});
dia.show();

progressdialog已停用

四種基本布局：
LinearLayout

RelativeLayout(推薦使用）:
android:layout_alignParentLeft/layout_alignParentRight/layout_alignParentTop/layout_alignParentBotton/layout_alignParentlayout_centerInParent/layout_above/layout_below/toLeftOf/toRightOf

FrameLayout:

android.support.percent.PercentFrameLayout:
compile 'com.android.support:percent:24.2.2
app:layout_widthPercentapp:layout_heightPercent

自定義布局：
<include layout="@layout/title" />
隱藏標題欄：

ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.hide();
        }

創建自定義控件：

    <lewanjiang.com.uicustomviews.TitleLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

public class TitleLayout extends LinearLayout {
    public TitleLayout(Context context, AttributeSet attrs) {
        super(context,attrs);
        LayoutInflater.from(context).inflate(R.layout.title,this);
       Button titleBack = (Button) findViewById(R.id.title_back);
        Button titleEdit = (Button) findViewById(R.id.title_edit);

        titleBack.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                ((Activity)getContext()).finish();
            }
        });
        titleEdit.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getContext(),"haha",Toast.LENGTH_SHORT).show();
            }
        });
    }
}

ListView簡單用法：

private String[] data = {"a","b","c","d","e","f","g"};
ArrayAdapter<String> ada = new ArrayAdapter<String>(
        MainActivity.this,android.R.layout.simple_list_item_1,data);
ListView lisVie = (ListView) findViewById(R.id.list_view);
lisVie.setAdapter(ada);

復雜用法：

public class Fruit {
    private String name;
    private int imageId;

    public Fruit(String name,int imageId) {
        this.name = name;
        this.imageId = imageId;
    }

    public String getName() {
        return name;
    }

    public int getImageId() {
        return imageId;
    }
}

public class FruitAdapter extends ArrayAdapter<Fruit> {
    private int resourceId;

    public FruitAdapter(Context context, int textViewResouceId, List<Fruit> objects) {
        super(context,textViewResouceId,objects);
        resourceId = textViewResouceId;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        Fruit fruit = getItem(position);
        View view;
        ViewHolder viewHolder;
        if (convertView == null) {
            view = LayoutInflater.from(getContext()).inflate(resourceId, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.fruitImage = (ImageView) view.findViewById(R.id.fruit_image);
            viewHolder.fruitName = (TextView) view.findViewById(R.id.fruit_name);
            view.setTag(viewHolder);
        } else {
            view = convertView;
            viewHolder = (ViewHolder) view.getTag();
        }
        viewHolder.fruitImage.setImageResource(fruit.getImageId());
        viewHolder.fruitName.setText(fruit.getName());
        return view;
    }

    class ViewHolder {
        ImageView fruitImage;
        TextView fruitName;
    }
}

public class MainActivity extends AppCompatActivity {
    private List<Fruit> fruitList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruits();
        FruitAdapter adapter = new FruitAdapter(MainActivity.this,R.layout.fruit_item,fruitList);
        ListView listView = (ListView) findViewById(R.id.list_view);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Fruit fruit = fruitList.get(position);
                Toast.makeText(MainActivity.this,fruit.getName(),Toast.LENGTH_SHORT).show();
            }
        });
    }

    private void initFruits() {
        for (int i = 0;i < 2;i++) {
            Fruit apple = new Fruit("Apple",R.drawable.ic_launcher_background);
            fruitList.add(apple);
            Fruit banana = new Fruit("Banana",R.drawable.ic_launcher_background);
            fruitList.add(banana);
        }
    }
}

1.概述：
RecyclerView的設計與ListView、GridView類似，也使用了Adapter，不過該Adapter并不是ListView中的Adapter，而是RecyclerView的一個靜態內部類。該Adapter有一個泛型參數VH，代表的就是ViewHolder。RecyclerView還封裝了一個ViewHolder類型，該類型中有一個itemView字段，代表的就是每一項數據的根視圖，需要在構造函數中傳遞給ViewHolder對象。RecyclerView這么設計相當于將ListView的Adapter進行了再次封裝，把getView函數中判斷是否含有緩存的代碼段封裝到RecyclerView內部，使這部分邏輯對用戶不可見。用戶只需要告訴RecyclerView每項數據是怎么樣的以及將數據綁定到每項數據上，分別對應的函數為onCreateViewHolder函數、onBindViewHolder函數，當然還需要通過getItemCount告訴RecyclerView有多少項數據，以往適用于ListView的 Adapter中的getView函數中的邏輯就不需要用戶來處理了。
基本用法如下，導入listview項目中的fruit類和fruit_item.xml：

public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder> {
    private List<Fruit> mFruLis;
    static class ViewHolder extends RecyclerView.ViewHolder {
        ImageView fruitImage;
        TextView fruitName;
        public ViewHolder(View vie) {
            super(vie);
            fruitImage = (ImageView) vie.findViewById(R.id.fruit_image);
            fruitName = (TextView) vie.findViewById(R.id.fruit_name);
        }
    }

    public FruitAdapter(List<Fruit> fruLis) {
        mFruLis = fruLis;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup par,int vieTyp) {
        View vie = LayoutInflater.from(par.getContext()).inflate(R.layout.fruit_item,par,false);
        ViewHolder hol = new ViewHolder(vie);
        return hol;
    }

    @Override
    public void onBindViewHolder(ViewHolder hol,int pos) {
        Fruit fru = mFruLis.get(pos);
        hol.fruitImage.setImageResource(fru.getImageId());
        hol.fruitName.setText(fru.getName());
    }

    @Override
    public int getItemCount() {
        return mFruLis.size();
    }
}

    RecyclerView recVie = (RecyclerView) findViewById(R.id.recycler_view);
    LinearLayoutManager layMan = new LinearLayoutManager(this);
    recVie.setLayoutManager(layMan);
    FruitAdapter ada = new FruitAdapter(fruLis);
    recVie.setAdapter(ada);

2.高級用法
RecyclerView的另一大特點就是將布局方式抽象為LayoutManager，默認提供了LinearLayoutManager、GridLayoutManager、StaggeredGridLayoutManager 3種布局，對應為線性布局、網格布局、交錯網格布局，如果這些都無法滿足你的需求，你還可以定制布局管理器實現特定的布局方式。
RecyclerView通過橋接的方式將布局職責抽離出去，使得RecyclerView變得更靈活。例如，如果用戶只需要修改RecyclerView的布局方式，只需要修改LayoutManager即可，而不需要操作復雜的RecyclerView類型。而ListView、GridView正好是相反的，它們只是布局方式不一樣，但卻是兩個類型，它們覆寫了基類AbsListView的layoutChildren函數來實現不同的布局。顯然，通過組合的形式要好于通過繼承，因此，RecyclerView在設計上也要好于AbsListView類族。

除此之外，RecyclerView對于Item View的控制也更為精細，可以通過ItemDecotation為Item View添加裝飾，也就是在Item View上進行二次加工；又可以用過ItemAnimator為Item View添加動畫。

實現橫向滾動：
fruit_item.xml 把布局改為垂直方向
MainActivity添加如下代碼：

layMan.setOrientation(LinearLayoutManager.HORIZONTAL);

瀑布流布局：
StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);

點擊事件：
修改FruitAdapter代碼如下：

    static class ViewHolder extends RecyclerView.ViewHolder {
        View fruitView;
        ImageView fruitImage;
        TextView fruitName;
        public ViewHolder(View vie) {
            super(vie);
            fruitView = vie;
            fruitImage = (ImageView) vie.findViewById(R.id.fruit_image);
            fruitName = (TextView) vie.findViewById(R.id.fruit_name);
        }
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup par,int vieTyp) {
        View vie = LayoutInflater.from(par.getContext()).inflate(R.layout.fruit_item,par,false);
        final ViewHolder hol = new ViewHolder(vie);
        hol.fruitView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int pos = hol.getAdapterPosition();
                Fruit fru = mFruLis.get(pos);
                Toast.makeText(v.getContext(),"you clicked view" + fru.getName(),Toast.LENGTH_SHORT).show();
            }
        });
        hol.fruitImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int pos = hol.getAdapterPosition();
                Fruit fru = mFruLis.get(pos);
                Toast.makeText(v.getContext(),"you clicked image" + fru.getName(),Toast.LENGTH_SHORT).show();
            }
        });
        return hol;
    }

UI最佳實踐：

public class Msg {
    public static final int TYPE_RECEIVED = 0;
    public static final int TYPE_SEND = 1;
    private String content;
    private int type;

    public Msg(String content,int type) {
        this.content = content;
        this.type = type;
    }

    public String getContent() {
        return content;
    }

    public int getType() {
        return type;
    }
}

public class MsgAdapter extends RecyclerView.Adapter<MsgAdapter.ViewHolder> {
    private List<Msg> mMsgList;

    static class ViewHolder extends RecyclerView.ViewHolder {
        LinearLayout leftLayout;
        LinearLayout rightLayout;
        TextView leftMsg;
        TextView rightMsg;

        public ViewHolder(View view) {
            super(view);
            leftLayout = (LinearLayout) view.findViewById(R.id.left_layout);
            rightLayout = (LinearLayout) view.findViewById(R.id.right_layout);
            leftMsg = (TextView) view.findViewById(R.id.left_msg);
            rightMsg = (TextView) view.findViewById(R.id.right_msg);
        }
    }

    public MsgAdapter(List<Msg> msgList) {
        mMsgList = msgList;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.msg_item,parent,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        Msg msg = mMsgList.get(position);
        if (msg.getType() == Msg.TYPE_RECEIVED) {
            holder.leftLayout.setVisibility(View.VISIBLE);
            holder.rightLayout.setVisibility(View.GONE);
            holder.leftMsg.setText(msg.getContent());
        } else if (msg.getType() == Msg.TYPE_SEND) {
            holder.rightLayout.setVisibility(View.VISIBLE);
            holder.leftLayout.setVisibility(View.GONE);
            holder.rightMsg.setText(msg.getContent());
        }
    }

    @Override
    public int getItemCount() {
        return mMsgList.size();
    }
}


String content = inputText.getText().toString();
                if (!"".equals(content)) {
                    Msg msg = new Msg(content,Msg.TYPE_SEND);
                    msgList.add(msg);
                    adapter.notifyItemInserted(msgList.size() - 1);
                    msgRecyclerview.scrollToPosition(msgList.size() - 1);
                    inputText.setText("");
                }

1.Fragment簡單用法
建left和right的xml文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <Button
        android:id="@+id/button"
        android:layout_gravity="center_horizontal"
        android:text="button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <TextView
        android:layout_gravity="center_horizontal"
        android:text="HAHA"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

建立left和right的類：

public class Left extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inf, ViewGroup container, Bundle savedInstanceState) {
        View view = inf.inflate(R.layout.left,container,false);
        return view;
    }
}
public class Right1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inf, ViewGroup container, Bundle savedInstanceState) {
        View view = inf.inflate(R.layout.right1,container,false);
        return view;
    }
}

修改activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent" >

    <fragment
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/left_fragment"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_weight="1" />

    <fragment
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/right_fragment"
        android:name="com.lewanjiang.fragmenttest.Right"
        android:layout_weight="1" />

</LinearLayout>

動態添加Fragment：
建Right1.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <TextView
        android:text="HEIHEI"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</LinearLayout>

建Right1類：

public class Right1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inf, ViewGroup container, Bundle savedInstanceState) {
        View view = inf.inflate(R.layout.right1,container,false);
        return view;
    }
}

修改activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent" >

    <fragment
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/left_fragment"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_weight="1" />

    <FrameLayout
        android:id="@+id/right_layout"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="match_parent">

    </FrameLayout>
</LinearLayout>

修改MainActivity:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button = (Button) findViewById(R.id.button);
        replaceFragment(new Right());
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                replaceFragment(new Right1());
            }
        });
    }

    private void replaceFragment(Fragment fra) {
        FragmentManager fraMan = getSupportFragmentManager();
        FragmentTransaction tra = fraMan.beginTransaction();
        tra.replace(R.id.right_layout,fra);
        tra.commit();
    }
}

完成。

模擬返回棧：

tra.addToBackStack(null);

活動調用碎片中方法：

Right rigFra = (Right) getFragmentManager().findFragmentById(R.id.right);

碎片調用活動中方法：
在碎片中：

MainActivity act = (MainActivity) getActivity();

同時也可以使用這個方法獲取Context。

fragment生命周期：onAttach(),onCreate(),onCreateView(),onActivityCreate(),onStart(),onResume(),onPause(),onStop(),onDestroyView(),onDestroy(),onDetach()

根據設備屏幕大小方向動態選擇加載哪個布局：
修改activity_main.xml文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent" >
    <fragment
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:id="@+id/left_fragment"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_weight="1" />
</LinearLayout>

在res目錄下新建layout_large文件夾,新建名為：activity_main.xml的布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <fragment
        android:id="@+id/left"
        android:name="com.lewanjiang.fragmenttest.Left"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1" />

    <fragment
        android:id="@+id/right"
        android:name="com.lewanjiang.fragmenttest.Right"
        android:layout_height="match_parent"
        android:layout_width="0dp"
        android:layout_weight="3" />
</LinearLayout>

最小寬度限定符：
新建layout-sw600dp文件夾，將上面第二個activity_main復制進去。

綜合應用——新聞應用：
1。build.gradle 中添加recyclerview支持
2.新建新聞類：News

public class News {
    private String title;
    private String content;
    public String getTitle(){
        return title;
    }
    public void setTitle(String title){
        this.title = title;
    }
    public String getContent(){
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
}

3.新建內容布局文件news_content_frag.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <LinearLayout
        android:id="@+id/visibility_layout"
        android:orientation="vertical"
        android:visibility="invisible"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            android:id="@+id/news_title"
            android:padding="10dp"
            android:textSize="20sp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

        <View
            android:layout_width="match_parent"
            android:layout_height="1dp"
            android:background="#000" />

        <TextView
            android:id="@+id/news_content"
            android:layout_weight="1"
            android:textSize="18sp"
            android:layout_width="match_parent"
            android:layout_height="0dp"/>

    </LinearLayout>

    <View
        android:layout_width="1dp"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:background="#000" />
</LinearLayout>

4.新建內容布局類NewsContentFragment，繼承Fragment:

public class NewsContentFragment extends Fragment {
    private View view;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.news_content_frag,container,false);
        return view;
    }

    public void refresh(String newsTitle,String newsContent) {
        View visibilityLayout = view.findViewById(R.id.visibility_layout);
        visibilityLayout.setVisibility(View.VISIBLE);
        TextView newsTitleText = (TextView)view.findViewById(R.id.news_title);
        TextView newsContentText = (TextView)view.findViewById(R.id.news_content);
        newsTitleText.setText(newsTitle);
        newsContentText.setText(newsContent);
    }
}

5.對小屏模式支持，新建Activity:NewsContentAcitivty和相應布局文件news_content.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.fragmentbestpractice.NewsContentActivity">

    <fragment
        android:id="@+id/news_content_fragment"
        android:name="com.lewanjiang.fragmentbestpractice.NewsContentFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>
public class NewsContentActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.news_content);
        String newsTitle = getIntent().getStringExtra("news_title");
        String newsContent = getIntent().getStringExtra("news_content");
        NewsContentFragment newsContentFragment = (NewsContentFragment) getSupportFragmentManager().findFragmentById(R.id.news_content_fragment);
        newsContentFragment.refresh(newsTitle,newsContent);
    }

    public static void actionStart(Context context,String newsTitle,String newsContent) {
        Intent intent = new Intent(context,NewsContentActivity.class);
        intent.putExtra("news_title",newsTitle);
        intent.putExtra("new_content",newsContent);
        context.startActivity(intent);
    }
}

6.新建用于顯示新聞列表的布局，news_title_frag.xml:

?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/news_title_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />
</LinearLayout>

7.新建news_item.xml作為recyclerview的子布局：

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/news_title"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
        />

8.新建NewsTitleFragment作為展示新聞列表的碎片：

public class NewsTitleFragment extends Fragment {
    private boolean isTwoPane;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.news_title_frag,container,false);
        RecyclerView newsTitleRecyclerView = (RecyclerView) view.findViewById(R.id.news_title_recycler_view);
        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        newsTitleRecyclerView.setLayoutManager(layoutManager);
        NewsAdapter adapter = new NewsAdapter(getNews());
        newsTitleRecyclerView.setAdapter(adapter);
        return view;
    }

    private List<News> getNews(){
        List<News> newsList = new ArrayList<>();
        for(int i=1;i<=50;i++) {
            News news = new News();
            news.setTitle("This is news title" + i);
            news.setContent("content" + i);
            newsList.add(news);
        }
        return newsList;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if (getActivity().findViewById(R.id.news_content_layout) != null) {
            isTwoPane = true;
        } else {
            isTwoPane = false;
        }
    }

    class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.ViewHolder> {
        private List<News> mNewsList;

        class ViewHolder extends RecyclerView.ViewHolder {
            TextView newsTitleText;
            public ViewHolder(View view) {
                super(view);
                newsTitleText = (TextView)view.findViewById(R.id.news_title);
            }
        }

        public NewsAdapter(List<News> newsList) {
            mNewsList = newsList;
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.news_item,parent,false);
            final ViewHolder holder = new ViewHolder(view);
            view.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    News news = mNewsList.get(holder.getAdapterPosition());
                    if (isTwoPane) {
                        NewsContentFragment newsContentFragment = (NewsContentFragment)getFragmentManager().findFragmentById(R.id.news_content_fragment);
                        newsContentFragment.refresh(news.getTitle(),news.getContent());
                        news.getContent();
                    } else {
                        NewsContentActivity.actionStart(getActivity(),news.getTitle(),news.getContent());
                    }
                }
            });
            return holder;
        }

        @Override
        public void onBindViewHolder(ViewHolder holder,int position) {
            News news = mNewsList.get(position);
            holder.newsTitleText.setText(news.getTitle());
        }

        @Override
        public int getItemCount() {
            return mNewsList.size();
        }
    }
}

9.修改activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.fragmentbestpractice.MainActivity">

    <fragment
        android:id="@+id/news_title_fragment"
        android:name="com.lewanjiang.fragmentbestpractice.NewsTitleFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>

10.新建layout-sw600dp支持大屏，在此文件夾下新建activity_main：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent">

    <fragment
        android:id="@+id/news_title_fragment"
        android:name="com.lewanjiang.fragmentbestpractice.NewsTitleFragment"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="match_parent" />
    <FrameLayout
        android:id="@+id/news_content_layout"
        android:layout_weight="3"
        android:layout_width="0dp"
        android:layout_height="match_parent">

        <fragment
            android:id="@+id/news_content_fragment"
            android:name="com.lewanjiang.fragmentbestpractice.NewsContentFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </FrameLayout>

</LinearLayout>

關于廣播

新建廣播接收器：

class NetworkChangeReceiver extends BroadcastReceiver{
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context,"network changes",Toast.LENGTH_SHORT).show();
    }
}

注冊廣播接收器：

private IntentFilter mIntentFilter;
private NetworkChangeReceiver mNetworkChangeReceiver;
    mIntentFilter = new IntentFilter();
    mIntentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
    mNetworkChangeReceiver = new NetworkChangeReceiver();
    registerReceiver(mNetworkChangeReceiver,mIntentFilter);

靜態注冊：

<receiver
    android:name=".MyReceiver"
    android:enabled="true"
    android:exported="true">
    <intent-filter>
        <action android:name="android.intent.action.MY_BORADCAST" />
    </intent-filter>
</receiver>

發送廣播：

Intent intent = new Intent("com.lewanjiang.broadcasttest.MY_BORADCAST");
sendBroadcast(intent);

發送有序廣播：

sendOrderedBroadcast(intent);

發送本地廣播：

LocalBroadcastManager locBroMan = LocalBroadcastManager.getInstance(this);
Intent int = new Intent("com.lewanjiang.broadcasttest.LOCAL_BROADCAST");
locBroMan.sendBroadcast(int);

注冊同普通廣播一樣，只是注銷時：

locBroMan.unregisterReceiver(localReceiver);

強制下線功能實現：
1.新建ActivityCollector類和BaseActivity類：

public class ActivityCollector {
    public static List<Activity> activities = new ArrayList<>();

    public static void addActivity(Activity activity) {
        activities.add(activity);
    }

    public static void removeActivity(Activity activity) {
        activities.remove(activity);
    }

    public static void finishAll() {
        for (Activity activity:activities) {
            if (!activity.isFinishing()) {
                activity.finish();
            }
        }
    }
}
public class BaseActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityCollector.addActivity(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
    }

2.新建一個空的Activity:LoginActivity，修改相應的activity_login.xml和LoginAcitivity:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.broadcastbestpractice1.LoginActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp">

        <TextView
            android:text="Account:"
            android:layout_width="90dp"
            android:layout_height="wrap_content"/>

        <EditText
            android:id="@+id/account"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp">

        <TextView
            android:text="Password:"
            android:layout_width="90dp"
            android:layout_height="wrap_content"/>
        <EditText
            android:id="@+id/password"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"/>

    </LinearLayout>

    <Button
        android:id="@+id/login"
        android:text="login"
        android:layout_width="match_parent"
        android:layout_height="60dp"/>
</LinearLayout>
public class LoginActivity extends BaseActivity {

    private EditText accountEdit;
    private EditText passwordEdit;
    private Button login;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        accountEdit = (EditText) findViewById(R.id.account);
        passwordEdit = (EditText) findViewById(R.id.password);
        login = (Button) findViewById(R.id.login);
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String account = accountEdit.getText().toString();
                String password = passwordEdit.getText().toString();
                if (account.equals("admin") && password.equals("123456")) {
                    Intent intent = new Intent(LoginActivity.this,MainActivity.class);
                    startActivity(intent);
                    finish();
                } else {
                    Toast.makeText(LoginActivity.this,"account or password wrong",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

3.修改activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.lewanjiang.broadcastbestpractice1.MainActivity">

    <Button
        android:id="@+id/force_offline"
        android:text="send force offline broadcast"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</android.support.constraint.ConstraintLayout>

4.修改MainActivity:

public class MainActivity extends BaseActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button forceOffline = (Button) findViewById(R.id.force_offline);
        forceOffline.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent("com.lewanjiang.broadcastbestpractice1.FORCE_OFFLINE");
                sendBroadcast(intent);
            }
        });
    }
}

5.注冊廣播接收器，修改BaseActivity如下：

public class BaseActivity extends AppCompatActivity {

    private ForceOfflineReceiver receiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityCollector.addActivity(this);
    }

    @Override
    protected void onResume(){
        super.onResume();
        IntentFilter intentFilter = new IntentFilter("com.lewanjiang.broadcastbestpractice1.FORCE_OFFLINE");
        receiver = new ForceOfflineReceiver();
        registerReceiver(receiver,intentFilter);
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (receiver != null) {
            unregisterReceiver(receiver);
            receiver=null;
        }
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
    }

    class ForceOfflineReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(final Context context, Intent intent) {
            AlertDialog.Builder builder = new AlertDialog.Builder(context);
            builder.setTitle("Warning");
            builder.setMessage("You are forced to be offline");
            builder.setCancelable(false);
            builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    ActivityCollector.finishAll();
                    Intent intent1 = new Intent(context,LoginActivity.class);
                    context.startActivity(intent1);
                }
            });
            builder.show();
        }
    }
}