DrawerLayout側滑菜單

之前寫過一篇關於SlidingMenu的側滑，谷歌官方的DrawerLayout側滑，唯一比較蛋疼的地方是手勢滑動的時候，需要滑動屏幕的最邊緣才能把側滑菜單拉出來，所以也順便修改了側滑菜單的有效響應距離。
代碼如下：

public class MainActivity extends Activity {
    private ListView mListView;
    private List<String> listData;
    private DrawerLayout drawerlayout;
    private Button start_slidingMenu;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView = (ListView) findViewById(R.id.listview);
        drawerlayout = (DrawerLayout) findViewById(R.id.drawerlayout);
        start_slidingMenu = (Button) findViewById(R.id.start_slidingMenu);
        listData = new ArrayList<>();
        initData();
//        drawerlayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);//禁用手勢滑動打開側滑菜單
        mListView.setAdapter(new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,listData));
        start_slidingMenu.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                drawerlayout.openDrawer(GravityCompat.START);//打開側滑菜單
            }
        });
        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                ToastUtil.showShort(MainActivity.this,"點擊了"+position);
                drawerlayout.closeDrawers();//關閉側滑菜單
            }
        });
    }

    private void initData() {
        for(int i=0;i<5;i++){
            listData.add("數據"+i);
        }
        try {
                //網上有修改的封裝
                Field  field = drawerlayout.getClass().getDeclaredField("mLeftDragger");
                field.setAccessible(true);
                ViewDragHelper mLeftDragger = (ViewDragHelper) field.get(drawerlayout);
                Field field1 = mLeftDragger.getClass().getDeclaredField("mEdgeSize");
                field1.setAccessible(true);
                DisplayMetrics metrics = new DisplayMetrics();
                getWindowManager().getDefaultDisplay().getMetrics(metrics);
                field1.setInt(mLeftDragger, (int) (metrics.widthPixels*0.3));//修改有效滑動響應寬度爲屏幕寬度的百分之30.
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

需要注意的是xml代碼是佈局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawerlayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.lenovo.demo.MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <Button
            android:id="@+id/start_slidingMenu"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:text="展開"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="#cccccc"
        android:orientation="vertical"
        android:tag="START">
        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/recharge_bg"
            android:scaleType="centerCrop"/>
        <ListView
            android:id="@+id/listview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
    </LinearLayout>
</android.support.v4.widget.DrawerLayout>

注意：首先，根節點就是android.support.v4.widget.DrawerLayout，
其次，裏面包含的第一個ViewGroup是Activity顯示的佈局，第二個ViewGroup或者view纔是側滑菜單的佈局，最後，需要側滑菜單佈局的根節點設置：android:layout_gravity=”start”（不建議使用left或者right）。
————————————————————————————————————————————————————————————————
如果想實現在拉出側滑菜單的帶有動畫效果的縮放效果的話，可以在側滑菜單View的跟佈局節點上打上一個標記，如：android:tag="START"

然後在初始化DrawerLayout的時候，設置一個側滑監聽：

drawerlayout.addDrawerListener(new DrawerLayout.DrawerListener() {
            @Override
            public void onDrawerSlide(View drawerView, float slideOffset) {
                View mContent = leftMenu.getChildAt(0);
                View mMenu = drawerView;
                float scale = 1 - slideOffset;
                float rightScale = 0.8f + scale * 0.2f;
                if (drawerView.getTag().equals("START")) {
                    float leftScale = 1 - 0.3f * scale;
                    ViewHelper.setScaleX(mMenu, leftScale);
                    ViewHelper.setScaleY(mMenu, leftScale);
                    ViewHelper.setAlpha(mMenu, 0.6f + 0.4f * (1 - scale));
                    ViewHelper.setTranslationX(mContent, mMenu.getMeasuredWidth() * (1 - scale));
                    ViewHelper.setPivotX(mContent, 0);
                    ViewHelper.setPivotY(mContent, mContent.getMeasuredHeight() / 2);
                    mContent.invalidate();
                    ViewHelper.setScaleX(mContent, rightScale);
                    ViewHelper.setScaleY(mContent, rightScale);
                } else {
                    ViewHelper.setTranslationX(mContent, -mMenu.getMeasuredWidth() * slideOffset);
                    ViewHelper.setPivotX(mContent, mContent.getMeasuredWidth());
                    ViewHelper.setPivotY(mContent, mContent.getMeasuredHeight() / 2);
                    mContent.invalidate();
                    ViewHelper.setScaleX(mContent, rightScale);
                    ViewHelper.setScaleY(mContent, rightScale);
                }
            }

            @Override
            public void onDrawerOpened(View drawerView) {

            }

            @Override
            public void onDrawerClosed(View drawerView) {

            }

            @Override
            public void onDrawerStateChanged(int newState) {

            }
        });

如果用在TabLayout中，還需要判斷一下，只有在position==0的情況下才允許右滑顯示側滑菜單，反之，要禁用掉側滑屬性

if(tab.getPosition()!=0){
                    drawerlayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED, GravityCompat.START);
                }else {
                    drawerlayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED, GravityCompat.START);
                }