package me.chenfuduo.myviewdraghelperusage.drag;
import android.content.Context;
import android.graphics.Color;
import android.graphics.PorterDuff;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
/**
* Created by Administrator on 2015/6/29.
*/
public class DragLayout extends FrameLayout {
private ViewDragHelper dragHelper;
private ViewGroup mLeftContent;
private ViewGroup mMainContent;//红色
int mHeight;
int mWidth;
int mRange;
private onDragStatusChangedListener listener;
Status mStatus = Status.Close;
/**
* 状态枚举
*/
public enum Status {
Close, Open, Draging
}
public interface onDragStatusChangedListener {
void onClose();
void onOpen();
void onDraging(float percent);
}
public void setDragStatusListener(onDragStatusChangedListener listener) {
this.listener = listener;
}
public Status getStatus() {
return mStatus;
}
public void setStatus(Status mStatus) {
this.mStatus = mStatus;
}
public DragLayout(Context context) {
this(context, null);
}
public DragLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public DragLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
//创建ViewDragHelper的静态工厂方法有两个，一个带float sensitivity参数，一个不带，这个参数的默认值是1.0f
//第一个参数是父view，也就是这里的DragLayout，给个this即可
//第二个参数(若有),是灵敏度，默认值是1.0f
//第三个参数是回调接口
//ViewDragHelper.create(this,1.0f,mCallback);
dragHelper = ViewDragHelper.create(this, mCallback);
}
/**
* 该接口默认实现了public boolean tryCaptureView(View child, int pointerId)方法
* 当然还需要实现很多其他的方法
*/
private ViewDragHelper.Callback mCallback = new ViewDragHelper.Callback() {
/**
* 根据返回结果决定当前child是否可以拖拽
* @param child 当前被拖拽的view
* @param pointerId 区分多点触摸的id
* @return
*/
@Override
public boolean tryCaptureView(View child, int pointerId) {
Log.e("Test", "child view：" + child.toString());
// return child == mMainContent;
return true;
}
/**
* 当capturedChild被捕获的时候调用
* @param capturedChild
* @param activePointerId
*/
@Override
public void onViewCaptured(View capturedChild, int activePointerId) {
Log.d("Test", "onViewCaptured--->capturedChild:" + capturedChild);
super.onViewCaptured(capturedChild, activePointerId);
}
/**
* 返回拖拽的范围，不对拖拽进行真正的限制，仅仅决定了动画执行速度
* @param child
* @return
*/
@Override
public int getViewHorizontalDragRange(View child) {
return mRange;
}
/**
* 根据建议值修正将要移动到的位置(水平)
* 此时没有发生真正的移动
* @param child 当前拖拽的view
* @param left 新的位置的建议值 left = oldLeft + dx; 其中oldLeft = child.getLeft().
* @param dx 位置变化量
* @return
*/
@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
super.clampViewPositionHorizontal(child, left, dx);
//向左 负的
// Log.e("Test","left:" + left + " dx:" + dx);
if (child == mMainContent) {
left = fixLeft(left);
}
return left;
}
/* @Override
public int clampViewPositionVertical(View child, int top, int dy) {
super.clampViewPositionVertical(child, top, dy);
//向上 负Log.e("Test","top:" + top + " dy:" + dy);
return top;
}*/
/**
* 当View位置改变的时候，处理要做的事情(更新状态，伴随动画，重绘界面)
* @param changedView
* @param left
* @param top
* @param dx
* @param dy
*/
@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
super.onViewPositionChanged(changedView, left, top, dx, dy);
int newLeft = left;
if (changedView == mLeftContent) {
//把当前的变化量传递给mMainContent
newLeft = mMainContent.getLeft() + dx;
}
newLeft = fixLeft(newLeft);
if (changedView == mLeftContent) {
//当左面板移动之后，再强制放回去
mLeftContent.layout(0, 0, 0 + mWidth, 0 + mHeight);
mMainContent.layout(newLeft, 0, newLeft + mWidth, 0 + mHeight);
}
dispatchDragEvent(newLeft);
//为了兼容低版本，每次修改值，进行重绘
invalidate();
}
/**
* 当View被释放的时候，执行动画
* @param releasedChild 被释放的View
* @param xvel 水平方向的速度 向右为正
* @param yvel 竖直方向的速度 向下为正
*/
@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
super.onViewReleased(releasedChild, xvel, yvel);
if (xvel == 0 && mMainContent.getLeft() > mRange / 2.0f) {
open();
} else if (xvel > 0) {
open();
} else {
close();
}
}
};
/**
* 更新状态，执行动画
*
* @param newLeft
*/
public void dispatchDragEvent(int newLeft) {
float percent = newLeft * 1.0f / mRange;
if (listener!=null){
listener.onDraging(percent);
}
//上一个状态
Status preStatus = mStatus;
//更新状态，执行回调
mStatus = updateStatus(percent);
if (mStatus != preStatus){
//状态发生变化
if (mStatus == Status.Close){
if (listener != null){
listener.onClose();
}
}else if (mStatus == Status.Open){
if (listener != null){
listener.onOpen();
}
}
}
animViews(percent);
}
private Status updateStatus(float percent) {
if (percent == 0.0f) {
return Status.Close;
} else if (percent == 1.0f) {
return Status.Open;
}
return Status.Draging;
}
private void animViews(float percent) {
//左面板缩放动画
//mLeftContent.setScaleX(0.5f + 0.5f*percent);
//上面注释的效果和下面的一模一样
mLeftContent.setScaleX(evaluate(percent, 0.5f, 1.0f));
mLeftContent.setScaleY(0.5f + 0.5f * percent);
//左面板平移动画
mLeftContent.setTranslationX(evaluate(percent, -mWidth / 2.0f, 0));
//左面板透明度变化
mLeftContent.setAlpha(evaluate(percent, 0.5f, 1.0f));
//主面板缩放动画
mMainContent.setScaleX(evaluate(percent, 1.0f, 0.8f));
mMainContent.setScaleY(evaluate(percent, 1.0f, 0.8f));
//背景：亮度变化(颜色变化)
getBackground().setColorFilter((Integer) evaluateColor(percent, Color.BLACK, Color.TRANSPARENT), PorterDuff.Mode.SRC_OVER);
}
public Float evaluate(float fraction, Number startValue, Number endValue) {
float startFloat = startValue.floatValue();
return startFloat + fraction * (endValue.floatValue() - startFloat);
}
public Object evaluateColor(float fraction, Object startValue, Object endValue) {
int startInt = (Integer) startValue;
int startA = (startInt >> 24) & 0xff;
int startR = (startInt >> 16) & 0xff;
int startG = (startInt >> 8) & 0xff;
int startB = startInt & 0xff;
int endInt = (Integer) endValue;
int endA = (endInt >> 24) & 0xff;
int endR = (endInt >> 16) & 0xff;
int endG = (endInt >> 8) & 0xff;
int endB = endInt & 0xff;
return (int) ((startA + (int) (fraction * (endA - startA))) << 24) |
(int) ((startR + (int) (fraction * (endR - startR))) << 16) |
(int) ((startG + (int) (fraction * (endG - startG))) << 8) |
(int) ((startB + (int) (fraction * (endB - startB))));
}
@Override
public void computeScroll() {
super.computeScroll();
//持续平滑动画(高频率调用)
if (dragHelper.continueSettling(true)) {
//如果返回true，动画还需要继续执行
ViewCompat.postInvalidateOnAnimation(this);
}
}
public void close() {
close(true);
}
/**
* 关闭
*/
public void close(boolean isSmooth) {
int finalLeft = 0;
if (isSmooth) {
//触发一个平滑的动画
if (dragHelper.smoothSlideViewTo(mMainContent, finalLeft, 0)) {
//返回true表示还没有移动到指定的位置，需要刷新界面
//参数传this,(child所在的ViewGroup)
ViewCompat.postInvalidateOnAnimation(this);
}
} else {
mMainContent.layout(finalLeft, 0, finalLeft + mWidth, 0 + mHeight);
}
}
public void open() {
open(true);
}
/**
* 打开
*/
public void open(boolean isSmooth) {
int finalLeft = mRange;
if (isSmooth) {
//触发一个平滑的动画
if (dragHelper.smoothSlideViewTo(mMainContent, finalLeft, 0)) {
//返回true表示还没有移动到指定的位置，需要刷新界面
//参数传this,(child所在的ViewGroup)
ViewCompat.postInvalidateOnAnimation(this);
}
} else {
mMainContent.layout(finalLeft, 0, finalLeft + mWidth, 0 + mHeight);
}
}
/**
* 根据范围修正左边值
*
* @param left
* @return
*/
private int fixLeft(int left) {
if (left < 0) {
return 0;
} else if (left > mRange) {
return mRange;
}
return left;
}
//下面重写的方法[onInterceptTouchEvent,onTouchEvent]可以理解为传递触摸事件(没有重写dispatchTouchEvent)
/*
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
return super.dispatchTouchEvent(ev);
}*/
/**
* 将事件拦截下来,相当于把自定义控件的事件交给ViewDragHelper去处理
*
* @param ev
* @return
*/
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
//传递给ViewDragHelper
return dragHelper.shouldInterceptTouchEvent(ev);
}
/**
* 将拦截下来的事件做处理
*
* @param event
* @return
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
//对多点触摸有点问题
try {
dragHelper.processTouchEvent(event);
} catch (Exception e) {
e.printStackTrace();
}
//返回true，持续接收事件
return true;
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
mLeftContent = (ViewGroup) getChildAt(0);
mMainContent = (ViewGroup) getChildAt(1);
}
/**
* 当尺寸有变化的时候调用,在onMeasure(...)方法后调用
*
* @param w
* @param h
* @param oldw
* @param oldh
*/
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mHeight = getMeasuredHeight();
mWidth = getMeasuredWidth();
mRange = (int) (mWidth * 0.6);
}
}