Android超简易侧滑菜单的实现

图示

自定义FrameLayout

import android.content.Context;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;

/**
* Created by yangshuai in the 10:57 of 2015.11.25 .
*/
public class DragViewTestGroup extends FrameLayout {

private View mMeneView; // 菜单view
private ViewDragHelper mViewDragHelper = null;
private int mMenuWidth; // 菜单宽度

public DragViewTestGroup(Context context) {
super(context);
init();
}

public DragViewTestGroup(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

public DragViewTestGroup(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}

@Override
protected void onFinishInflate() {
super.onFinishInflate();

/* 子 view 的最后一个作为菜单 */
mMeneView = getChildAt(getChildCount() - 1);
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);

/* 获取菜单的宽度 */
mMenuWidth = mMeneView.getMeasuredWidth();
}

private void init() {
mViewDragHelper = ViewDragHelper.create(this, callback);
mViewDragHelper.setEdgeTrackingEnabled(ViewDragHelper.EDGE_LEFT); // 启用边缘追踪
}

/* 回调 */
private ViewDragHelper.Callback callback = new ViewDragHelper.Callback() {

@Override
public boolean tryCaptureView(View child, int pointerId) {

/* 如果布局是菜单布局 */
return mMeneView == child;
}

@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {

/* 如果你拖动菜单的左边距大于0， 则禁止拖动*/
if (left > 0) {
return 0;
}
return left;
}

@Override
public int clampViewPositionVertical(View child, int top, int dy) {

/* 禁止垂直拖动 */
return 0;
}

@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
super.onViewReleased(releasedChild, xvel, yvel);

/* 当拖动到宽度的三分之二时释放展开菜单，否则隐藏 */
if (mMeneView.getRight() < mMenuWidth / 3 * 2) {
mViewDragHelper.smoothSlideViewTo(mMeneView, -mMenuWidth + 1, 0);
ViewCompat.postInvalidateOnAnimation(DragViewTestGroup.this);
} else {
mViewDragHelper.smoothSlideViewTo(mMeneView, 0, 0);
ViewCompat.postInvalidateOnAnimation(DragViewTestGroup.this);
}
}

@Override
public void onEdgeDragStarted(int edgeFlags, int pointerId) {
super.onEdgeDragStarted(edgeFlags, pointerId);

/* 检测是否是左边缘拖动 */
if (edgeFlags == ViewDragHelper.EDGE_LEFT) {
mViewDragHelper.captureChildView(mMeneView, pointerId);
}
}

@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
super.onViewPositionChanged(changedView, left, top, dx, dy);

/* 当位置大于0时移动到0 */
if (changedView == mMeneView && left > 0) {
mViewDragHelper.smoothSlideViewTo(mMeneView, 0, 0);
ViewCompat.postInvalidateOnAnimation(DragViewTestGroup.this);
}
}
};

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

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

@Override
public void computeScroll() {
if (mViewDragHelper.continueSettling(true)) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
}

布局中的使用

<?xml version="1.0" encoding="utf-8"?>
<com.magus.trainingfirstapp.view.DragViewTestGroup
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.magus.trainingfirstapp.module.customviews.charting.ViewDragHelperTestActivity">

<TextView
android:layout_width="100dp"
android:layout_height="100dp"
android:background="@color/black" />

<!-- 菜单布局 -->
<LinearLayout
android:layout_width="300dp"
android:layout_marginLeft="-300dp"
android:layout_height="match_parent"
android:background="@color/blue">
</LinearLayout>
</com.magus.trainingfirstapp.view.DragViewTestGroup>

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