ViewDragHelper实现QQ侧滑效果

<com.yctc.drag.DragLayout xmlns:android="http://scheR_235_11845@as.android.com/apk/res/android"
 xmlns:tools="http://scheR_235_11845@as.android.com/tools"
 android:id="@+id/dl"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:BACkground="@drawable/bg"
 tools:context=".MainActivity" >

 <LinearLayout
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  android:paddingBottom="50dp"
  android:paddingLeft="10dp"
  android:paddingRight="50dp"
  android:paddingTop="50dp" >

  <ImageView
   android:layout_width="50dp"
   android:layout_height="50dp"
   android:src="@drawable/head" />

  <ListView
   android:id="@+id/lv_left"
   android:layout_width="match_parent"
   android:layout_height="match_parent" >
  </ListView>
 </LinearLayout>

 <com.yctc.drag.MyLinearLayout
  android:id="@+id/mll"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:BACkground="#ffffff"
  android:orientation="vertical" >

  <RelativeLayout
   android:layout_width="match_parent"
   android:layout_height="50dp"
   android:BACkground="#18B6EF"
   android:gravity="center_vertical" >

   <ImageView
    android:id="@+id/iv_header"
    android:layout_width="30dp"
    android:layout_height="30dp"
    android:layout_marginLeft="15dp"
    android:src="@drawable/head" />

   <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:text="Header" />
  </RelativeLayout>

  <ListView
   android:id="@+id/lv_main"
   android:layout_width="match_parent"
   android:layout_height="match_parent" >
  </ListView>
 </com.yctc.drag.MyLinearLayout>
</com.yctc.drag.DragLayout>

public class DragLayout extends FrameLayout {

 private static final String TAG = "TAG";
 private ViewDragHelper mDragHelper;
 private ViewGroup mLeftContent;
 private ViewGroup mMainContent;
 private OnDragStatuschangelistener mListener;
 private Status mStatus = Status.Close;

 /**
  * 状态枚举
  */
 public static enum Status {
  Close,Open,Draging;
 }
 public interface OnDragStatuschangelistener{
  void onClose();
  void onopen();
  void onDraging(float percent);
 }

 public Status getStatus() {
  return mStatus;
 }

 public void setStatus(Status mStatus) {
  this.mStatus = mStatus;
 }

 public void setDragStatusListener(OnDragStatuschangelistener mListener){
  this.mListener = mListener;
 }

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

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

 public DragLayout(Context context,AttributeSet attrs,int defStylE) {
  super(context,defStylE);

  // a.初始化 (通过静态方法) 
  mDragHelper = ViewDragHelper.create(this,mCallBACk);

 }

 ViewDragHelper.CallBACk mCallBACk = new ViewDragHelper.CallBACk() {
  // c. 重写事件

  // 1. 根据返回结果决定当前child是否可以拖拽
  // child 当前被拖拽的View
  // pointerId 区分多点触摸的id
  @Override
  public Boolean tryCaptureView(View child,int pointerId) {
   Log.d(tag,"tryCaptureView: " + child);
   return true;
  };

  @Override
  public void onViewCaptured(View capturedChild,int activePointerId) {
   Log.d(tag,"onViewCaptured: " + capturedChild);
   // 当capturedChild被捕获时,调用.
   super.onViewCaptured(capturedChild,activePointerId);
  }

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

  // 2. 根据建议值 修正将要移动到的(横向)位置 (重要)
  // 此时没有发生真正的移动
  public int clampViewPositionHorizontal(View child,int left,int dX) {
   // child: 当前拖拽的View
   // left 新的位置的建议值,dx 位置变化量
   // left = oldLeft + dx;
   Log.d(tag,"clampViewPositionHorizontal: " 
     + "oldLeft: " + child.getLeft() + " dx: " + dx + " left: " +left);

   if(child == mMainContent){
    left = fixLeft(left);
   }
   return left;
  }

  // 3. 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)
  // 此时,View已经发生了位置的改变
  @Override
  public void onViewPositionChanged(View changedView,int top,int dx,int dy) {
   // changedView 改变位置的View
   // left 新的左边值
   // dx 水平方向变化量
   super.onViewPositionChanged(changedView,left,top,dx,dy);
   Log.d(tag,"onViewPositionChanged: " + "left: " + left + " dx: " + dX);

   int newLeft = left;
   if(changedView == mLeftContent){
    // 把当前变化量传递给mMainContent
    newLeft = mMainContent.getLeft() + dx;
   }

   // 进行修正
   newLeft = fixLeft(newLeft);

   if(changedView == mLeftContent) {
    // 当左面板移动之后,再强制放回去.
    mLeftContent.layout(0,0 + mWidth,0 + mHeight);
    mMainContent.layout(newLeft,newLeft + mWidth,0 + mHeight);
   }
   // 更新状态,执行动画
   dispatchDragEvent(newLeft);

   // 为了兼容低版本,每次修改值之后,进行重绘
   invalidate();
  }

  // 4. 当View被释放的时候,处理的事情(执行动画)
  @Override
  public void onViewReleased(View releasedChild,float xvel,float yvel) {
   // View releasedChild 被释放的子View 
   // float xvel 水平方向的速度,向右为+
   // float yvel 竖直方向的速度,向下为+
   Log.d(tag,"onViewReleased: " + "xvel: " + xvel + " yvel: " + yvel);
   super.onViewReleased(releasedChild,xvel,yvel);

   // 判断执行 关闭/开启
   // 先考虑所有开启的情况,剩下的就都是关闭的情况
   if(xvel == 0 && mMainContent.getLeft() > mRange / 2.0f){
    open();
   }else if (xvel > 0) {
    open();
   }else {
    close();
   }

  }

  @Override
  public void onViewDragStateChanged(int statE) {
   // TODO Auto-generated method stub
   super.onViewDragStateChanged(statE);
  }

 };

 /**
  * 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;
 }

 protected void dispatchDragEvent(int newLeft) {
  float percent = newLeft * 1.0f/ mRange;
  //0.0f -> 1.0f
  Log.d(tag,"percent: " + percent);

  if(mListener != null){
   mlistener.onDraging(percent);
  }

  // 更新状态,执行回调
  Status preStatus = mStatus;
  mStatus = updateStatus(percent);
  if(mStatus != preStatus){
   // 状态发生变化
   if(mStatus == Status.ClosE){
    // 当前变为关闭状态
    if(mListener != null){
     mlistener.onClose();
    }
   }else if (mStatus == Status.Open) {
    if(mListener != null){
     mlistener.onopen();
    }
   }
  }

//  * 伴随动画:
  animViews(percent);

 }

 private Status updateStatus(float percent) {
  if(percent == 0f){
   return Status.Close;
  }else if (percent == 1.0f) {
   return Status.Open;
  }
  return Status.Draging;
 }

 private void animViews(float percent) {
  //  > 1. 左面板: 缩放动画,平移动画,透明度动画
     // 缩放动画 0.0 -> 1.0 >>> 0.5f -> 1.0f >>> 0.5f * percent + 0.5f
   //  mLeftContent.setScaleX(0.5f + 0.5f * percent);
   //  mLeftContent.setScaleY(0.5f + 0.5f * percent);
     ViewHelper.setScaleX(mLeftContent,evaluate(percent,0.5f,1.0f));
     ViewHelper.setScaleY(mLeftContent,0.5f + 0.5f * percent);
     // 平移动画: -mWidth / 2.0f -> 0.0f
     ViewHelper.setTranslationX(mLeftContent,-mWidth / 2.0f,0));
     // 透明度: 0.5 -> 1.0f
     ViewHelper.setAlpha(mLeftContent,1.0f));

  //  > 2. 主面板: 缩放动画
     // 1.0f -> 0.8f
     ViewHelper.setScaleX(mMainContent,1.0f,0.8f));
     ViewHelper.setScaleY(mMainContent,0.8f));

  //  > 3. 背景动画: 亮度变化 (颜色变化)
     getBACkground().setColorFilter((Integer)evaluateColor(percent,Color.bLACK,Color.TRANSPARENT),Mode.SRC_OVER);
 }

 /**
  * 估值器
  * @param fraction
  * @param startValue
  * @param endValue
  * @return
  */
 public Float evaluate(float fraction,number startValue,number endvalue) {
  float startFloat = startValue.floatValue();
  return startFloat + fraction * (endValue.floatValue() - startFloat);
 }
 /**
  * 颜色变化过度
  * @param fraction
  * @param startValue
  * @param endValue
  * @return
  */
 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();

  // 2. 持续平滑动画 (高频率调用)
  if(mDragHelper.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){
   // 1. 触发一个平滑动画
   if(mDragHelper.smoothSlideViewTo(mMainContent,finalLeft,0)){
    // 返回true代表还没有移动到指定位置,需要刷新界面.
    // 参数传this(child所在的ViewGroup)
    ViewCompat.posTinvalidateOnAnimation(this);
   }
  }else {
   mMainContent.layout(finalLeft,finalLeft + mWidth,0 + mHeight);
  }
 }

 public void open(){
  open(true);
 }
 /**
  * 开启
  */
 public void open(Boolean isSmooth) {
  int finalLeft = mRange;
  if(isSmooth){
   // 1. 触发一个平滑动画
   if(mDragHelper.smoothSlideViewTo(mMainContent,0 + mHeight);
  }
 }

 privatE int mHeight;
 privatE int mWidth;
 privatE int mRange;

 // b.传递触摸事件
 @Override
 public Boolean onInterceptTouchEvent(MotionEvent ev) {
  // 传递给mDragHelper
  return mDragHelper.shouldInterceptTouchEvent(ev);
 }
 @Override
 public Boolean onTouchEvent(MotionEvent event) {
  try {
   mDragHelper.processTouchEvent(event);
  } catch (Exception E) {
   e.printStackTrace();
  }
  // 返回true,持续接受事件
  return true;
 }

 @Override
 protected void onFinishInflate() {
  super.onFinishInflate();
  // Github
  // 写注释
  // 容错性检查 (至少有俩子View,子View必须是ViewGroup的子类)

  if(getChildCount() < 2){
   throw new IllegalStateException("布局至少有俩孩子. Your ViewGroup must have 2 children at least.");
  }
  if(!(getChildAt(0) instanceof ViewGroup && getChildAt(1) instanceof ViewGroup)){
   throw new IllegalArgumentexception("子View必须是ViewGroup的子类. Your children must be an instance of ViewGroup");
  }

  mLeftContent = (ViewGroup) getChildAt(0);
  mMainContent = (ViewGroup) getChildAt(1);
 }

 @Override
 protected void onSizeChanged(int w,int h,int oldw,int oldh) {
  super.onSizeChanged(w,h,oldw,oldh);
  // 当尺寸有变化的时候调用

  mHeight = getMeasuredHeight();
  mWidth = getMeasuredWidth();

  // 移动的范围
  mRange = (int) (mWidth * 0.6f);

 }

}

public class MyLinearLayout extends LinearLayout {

 private DragLayout mDragLayout;

 public MyLinearLayout(Context context) {
  super(context);
 }

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

 public void setDraglayout(DragLayout mDragLayout){
  this.mDragLayout = mDragLayout;
 }

 @Override
 public Boolean onInterceptTouchEvent(MotionEvent ev) {
  // 如果当前是关闭状态,按之前方法判断
  if(mDragLayout.getStatus() == Status.ClosE){
   return super.onInterceptTouchEvent(ev);
  }else {
   return true;
  }
 }

 @Override
 public Boolean onTouchEvent(MotionEvent event) {
  // 如果当前是关闭状态,按之前方法处理
  if(mDragLayout.getStatus() == Status.ClosE){
   return super.onTouchEvent(event);
  }else {
   // 手指抬起,执行关闭操作
   if(event.getAction() == MotionEvent.ACTION_Up){
    mDragLayout.close();
   }

   return true;
  }
 }

}

public class MainActivity extends Activity {

 private static final String TAG = "TAG";

 @Override
 protected void onCreate(Bundle savedInstanceStatE) {
  super.onCreate(savedInstanceStatE);
  requestWindowFeature(Window.FEATURE_NO_titlE);
  setContentView(R.layout.activity_main);

  final ListView mLeftList = (ListView) findViewById(R.id.lv_left);
  final ListView mMainList = (ListView) findViewById(R.id.lv_main);
  final ImageView mHeaderImage = (ImageView) findViewById(R.id.iv_header);
  MyLinearLayout mLinearLayout = (MyLinearLayout) findViewById(R.id.mll);

  // 查找Draglayout,设置监听
  DragLayout mDragLayout = (DragLayout) findViewById(R.id.dl);

  // 设置引用
  mLinearLayout.setDraglayout(mDragLayout);

  mDragLayout.setDragStatusListener(new OnDragStatuschangelistener() {

   @Override
   public void onopen() {
    Utils.showToast(MainActivity.this,"onOpen");
    // 左面板ListView随机设置一个条目
    Random random = new Random();

    int nexTint = random.nexTint(50);
    mLeftList.smoothScrollToPosition(nextint);

   }

   @Override
   public void onDraging(float percent) {
    Log.d(tag,"onDraging: " + percent);// 0 -> 1
    // 更新图标的透明度
    // 1.0 -> 0.0
    ViewHelper.setAlpha(mHeaderImage,1 - percent);
   }

   @Override
   public void onClose() {
    Utils.showToast(MainActivity.this,"onClose");
    // 让图标晃动
//    mHeaderImage.setTranslationX(translationX)
    ObjectAnimator mAnim = ObjectAnimator.ofFloat(mHeaderImage,"translationX",15.0f);
    mAnim.seTinterpolator(new CycleInterpolator(4));
    mAnim.setDuration(500);
    mAnim.start();
   }
  });

  mLeftList.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,Cheeses.scheeseStrings){
   @Override
   public View getView(int position,View convertView,ViewGroup parent) {
    View view = super.getView(position,convertView,parent);
    TextView mText = ((TextView)view);
    mText.setTextColor(Color.WHITE);
    return view;
   }
  });

  mMainList.setAdapter(new ArrayAdapter<String>(this,Cheeses.NAMES))  
 }
}