使用ViewDragHelper实现简单的Drawerlayout

1.继承FrameLayou

public class MyDrawLayout extends FrameLayout {
    private ViewDragHelper viewDragHelper;
    private LinearLayout cehuaView;
    private LinearLayout contentView;
    private boolean isOpen = false;//是否开启状态

    public MyDrawLayout(@NonNull Context context) {
        super(context);
        init();
    }

    public MyDrawLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MyDrawLayout(@NonNull Context context, @Nullable AttributeSet attrs, @AttrRes int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        viewDragHelper = ViewDragHelper.create(this, 1.0f, new ViewDragHelper.Callback() {
            @Override
            public boolean tryCaptureView(View child, int pointerId) {
                return child == cehuaView;//设置只有侧滑内容能滑动
            }

            @Override
            public int clampViewPositionHorizontal(View child, int left, int dx) {
                if (child == cehuaView) {//判断侧滑块的滑动距离
                    if (left > 0) {
                        return 0;
                    }
                }
                return left;
            }

            @Override
            public int clampViewPositionVertical(View child, int top, int dy) {
                int topBound = getPaddingTop();
                int bottomBound = getHeight() - child.getHeight() - topBound;
                return Math.min(Math.max(top, topBound), bottomBound);
            }

            @Override
            public void onViewReleased(View releasedChild, float xvel, float yvel) {
                if (releasedChild == cehuaView) {
                    //判断如果滑动距离大于滑动模块的一半时候显示出来，没有的话收缩回去
                    if (releasedChild.getX() + releasedChild.getWidth() < releasedChild.getWidth() / 2) {
                        // TODO 隐藏
                        viewDragHelper.smoothSlideViewTo(releasedChild, -releasedChild.getWidth(), 0);
                        isOpen = false;
                    } else {
                        // TODO 显示
                        viewDragHelper.smoothSlideViewTo(releasedChild, 0, 0);
                        isOpen = true;
                    }
                    invalidate();
                }
            }

            @Override
            public void onEdgeTouched(int edgeFlags, int pointerId) {
                viewDragHelper.captureChildView(cehuaView, pointerId);
            }

            @Override
            public int getViewHorizontalDragRange(View child) {
                //当child里面有消耗事件的时候，需要返回大于0才能水平移动
                return 1;
            }
            @Override
            public int getViewVerticalDragRange(View child) {
                //当child里面有消耗事件的时候，需要返回大于0才能垂直移动
                return 1;
            }
        });
        //开启边界检测
        viewDragHelper.setEdgeTrackingEnabled(ViewDragHelper.EDGE_LEFT);
    }

    @Override
    public void computeScroll() {
        if (viewDragHelper.continueSettling(true)) {
            invalidate();
        }
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        //侧滑view
        cehuaView.layout(-cehuaView.getMeasuredWidth(), 0, 0, cehuaView.getMeasuredHeight());
        //内容view
        contentView.layout(0, 0, contentView.getMeasuredWidth(), contentView.getMeasuredHeight());
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        cehuaView = (LinearLayout) getChildAt(1);
        contentView = (LinearLayout) getChildAt(0);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return viewDragHelper.shouldInterceptTouchEvent(ev);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        viewDragHelper.processTouchEvent(event);
        return true;
    }

    public boolean isOpen() {
        return isOpen;
    }

    public void openDrawer() {
        viewDragHelper.smoothSlideViewTo(cehuaView, 0, 0);
        isOpen = true;
        invalidate();
    }

    public void closeDrawer() {
        viewDragHelper.smoothSlideViewTo(cehuaView, -cehuaView.getWidth(), 0);
        isOpen = false;
        invalidate();
    }
}

2.在XML中使用

3.在代码中使用

public class MainActivity extends AppCompatActivity {
    private MyDrawLayout myDrawLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);
        myDrawLayout = (MyDrawLayout) findViewById(R.id.mydraw);
    }

    public void change(View view) {
        if(myDrawLayout.isOpen()) {
            myDrawLayout.closeDrawer();
        }else {
            myDrawLayout.openDrawer();
        }
    }
}