ViewDragHelper 实现侧滑

ViewDragHelperde 侧滑的实现

自定义View继承自RelativeLayout

布局使用ListView 和 RecyclerView（如果继承FrameLayout会显示不全，必须继承RelativeLayout）

布局中包含两个View 用include 导入

<com.baima.swipedelete.SwipeDelete xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/swipeDelete"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">

<include layout="@layout/layout_content"
/>

<include layout="@layout/layout_delete"/>

</com.baima.swipedelete.SwipeDelete>

SwipeDelete类

public class SwipeDelete extends RelativeLayout {

private ViewDragHelper dragHelper;
private View content;
private View delete;
private int deleteWidth;

public SwipeDelete(Context context) {
this(context, null);
}

public SwipeDelete(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}

public SwipeDelete(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
dragHelper = ViewDragHelper.create(this, callback);
}

@Override
protected void onFinishInflate() {
super.onFinishInflate();
content = getChildAt(0);
delete = getChildAt(1);
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//获取宽和高
deleteWidth = delete.getMeasuredWidth();
}

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
content.layout(0, 0, content.getMeasuredWidth(), content.getMeasuredHeight());
delete.layout(content.getMeasuredWidth(), 0, content.getMeasuredWidth() + delete.getMeasuredWidth(), delete.getMeasuredHeight());

}

//ViewDragHelper拦截事件
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
boolean result = dragHelper.shouldInterceptTouchEvent(ev);
return result;
}

private float downX, downY;
private long downTime;

//自己消费事件
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
downX = event.getX();
downY = event.getY();
downTime = System.currentTimeMillis();
if (mlistener != null) {
mlistener.onTouchDown(SwipeDelete.this);
}
break;
case MotionEvent.ACTION_MOVE:
float moveX = event.getX();
float moveY = event.getY();
//1.获取移动的dx和dy
float dx = moveX - downX;
float dy = moveY - downY;
//2.判断谁大就是偏向于谁的方向
if (Math.abs(dx) > Math.abs(dy)) {
//说明偏向于水平，我们就认为是想滑动条目，则请求listview不要拦截
requestDisallowInterceptTouchEvent(true);
}
break;
case MotionEvent.ACTION_UP:
//1.按下抬起的时间
long duration = System.currentTimeMillis() - downTime;
//2.计算按下抬起的距离
float deltaX = event.getX() - downX;
float deltaY = event.getY() - downY;
float distance = (float) Math.sqrt(Math.pow(deltaX, 2) + Math.pow(deltaY, 2));
//如果按下抬起的时间小于500，并且按下抬起的距离小于8像素,认为是满足了执行点击的条件
if (duration< ViewConfiguration.getLongPressTimeout()&&distance<ViewConfiguration.getTouchSlop()){
//作用就是执行OnClickListener的onClick方法
performClick();
}
break;
}
dragHelper.processTouchEvent(event);
return true;
}

private ViewDragHelper.Callback callback = new ViewDragHelper.Callback() {
@Override
public boolean tryCaptureView(View child, int pointerId) {
return true;
}

@Override
public int getViewHorizontalDragRange(View child) {
return 1;
}

@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
Log.e("222", "left=" + left);
if (child == content) {
left = getLeft(left);
} else if (child == delete) {
if (left < content.getMeasuredWidth() - delete.getMeasuredWidth()) {

left = content.getMeasuredWidth() - delete.getMeasuredWidth();

} else if (left > content.getMeasuredWidth()) {
left = content.getMeasuredWidth();
}
}

return left;
}

@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
super.onViewPositionChanged(changedView, left, top, dx, dy);
if (changedView == content) {
//让delete伴随移动
int newLeft = delete.getLeft() + dx;
Log.e("tag", "getleft" + delete.getLeft() + "dx===" + dx);
delete.layout(newLeft, 0, newLeft + delete.getMeasuredWidth(), delete.getBottom());

} else if (changedView == delete) {
//让content伴随移动
int newLeft = content.getLeft() + dx;
content.layout(newLeft, 0, newLeft + content.getMeasuredWidth(), content.getBottom());
}

if (content.getLeft() == 0) {
//关闭了content
if (mlistener != null) {
mlistener.close(SwipeDelete.this);
}
} else if (content.getLeft() == -delete.getMeasuredWidth()) {
//打开了content
if (mlistener != null) {
mlistener.open(SwipeDelete.this);
}
}

}

//手指抬起的释放
@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
super.onViewReleased(releasedChild, xvel, yvel);
if (content.getLeft() > -deleteWidth / 2) {
//关闭
onClose();
} else {
onOpen();
}

}

};

public void onOpen() {
dragHelper.smoothSlideViewTo(content, -deleteWidth, 0);
ViewCompat.postInvalidateOnAnimation(this);
}

public void onClose() {
dragHelper.smoothSlideViewTo(content, 0, 0);
ViewCompat.postInvalidateOnAnimation(this);
}

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

}

private int getLeft(int left) {
if (left > 0) {
left = 0;
} else if (left < -delete.getMeasuredWidth()) {
left = -delete.getMeasuredWidth();
}
return left;
}

private OnSwipeDeleteListener mlistener;

public void setOnSwipeDeleteListener(OnSwipeDeleteListener listener) {
this.mlistener = listener;
}

public interface OnSwipeDeleteListener {
void open(SwipeDelete swipe);

void close(SwipeDelete swipe);

void onTouchDown(SwipeDelete swipe);

}

Adapter实现这个类回调