Android 中通过ViewDragHelper实现ListView的Item的侧拉划出效果

/**  * Created by mChenys on 2015/12/26.  */ public class SwipeLayout extends FrameLayout {   private ViewDragHelper.Callback mCallback;   private ViewDragHelper mDragHelper;   private View mBackView; //item的侧边布局   private View mFrontView;//当前显示的item布局   private int mWidth; //屏幕的宽度,mFrontView的宽度   private int mHeight; //mFrontView的高度   private int mRange;//mFrontView侧拉时向左移动的最大距离,即mBackView的宽度   public SwipeLayout(Context context) {     this(context, null);   }   public SwipeLayout(Context context, AttributeSet attrs) {     this(context, attrs, 0);   }   public SwipeLayout(Context context, AttributeSet attrs, int defStyleAttr) {     super(context, attrs, defStyleAttr);     init();   }   //1.初始ViewDragHelper   private void init() {     mCallback = new ViewDragHelper.Callback() {       //3.在回调方法中处理触摸事件       @Override       public boolean tryCaptureView(View child, int pointerId) {         return true; //允许所有子控件的滑动       }       //设定滑动的边界值       @Override       public int clampViewPositionHorizontal(View child, int left, int dx) {         if (child == mFrontView) {           //前景View的滑动范围是(0~ -mRange)           if (left > 0) {             left = 0;           } else if (left < -mRange) {             left = -mRange;           }         }         if (child == mBackView) {           //背景View的滑动范围是(mWidth - mRange ~ mWidth)           if (left > mWidth) {             left = mWidth;           } else if (left < (mWidth - mRange)) {             left = mWidth - mRange;           }         }         //返回修正过的建议值         return left;       }       //监听View的滑动位置的改变,同步前景View和背景View的滑动事件       @Override       public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {         if (changedView == mFrontView) {           //当滑动前景View时,也需要滑动背景View           mBackView.offsetLeftAndRight(dx);         } else if (changedView == mBackView) {           //当滑动背景View时,也需要滑动前景View           mFrontView.offsetLeftAndRight(dx);         }         // 兼容老版本         invalidate();       }       //处理释放后的开启和关闭动作       @Override       public void onViewReleased(View releasedChild, float xvel, float yvel) {         if (xvel < 0) {           //有向左滑动的速度,则打开           open();         } else if (xvel == 0 && mFrontView.getLeft() < -mRange / 2.0f) {           //前景View向左滑动的left小于背景View宽度一半的负值时,打开           open();         } else {           //其他情况为关闭           close();         }       }     };     mDragHelper = ViewDragHelper.create(this, mCallback);   }   //2.传递触摸事件   @Override   public boolean onInterceptTouchEvent(MotionEvent ev) {     return mDragHelper.shouldInterceptTouchEvent(ev);   }   @Override   public boolean onTouchEvent(MotionEvent event) {     try {       mDragHelper.processTouchEvent(event);     } catch (Exception e) {       e.printStackTrace();     }     return true;   }   //获取子控件的引用   @Override   protected void onFinishInflate() {     super.onFinishInflate();     mBackView = getChildAt(0); //获取背景View,即展示数据的Item的右边隐藏的侧滑布局     mFrontView = getChildAt(1);//获取前景View,即展示数据的Item   }   //获取子控件的相关宽高信息   @Override   protected void onSizeChanged(int w, int h, int oldw, int oldh) {     super.onSizeChanged(w, h, oldw, oldh);     mWidth = mFrontView.getMeasuredWidth();     mHeight = mFrontView.getMeasuredHeight();     mRange = mBackView.getMeasuredWidth();   }   //确定子控件的初始位置   @Override   protected void onLayout(boolean changed, int left, int top, int right, int bottom) {     super.onLayout(changed, left, top, right, bottom);     layoutChildView(false);   }   /**    * 放置子控件的位置    *    * @param isOpen 是否是打开前景View,true打开,false关闭    */   private void layoutChildView(boolean isOpen) {     //计算前景View的位置,将坐标信息封装到矩形中     Rect fontRect = computerFontViewRect(isOpen);     //摆放前景View     mFrontView.layout(fontRect.left, fontRect.top, fontRect.right, fontRect.bottom);     //摆放背景View,left坐标是前景View的right坐标     int left = fontRect.right;     mBackView.layout(left, 0, left + mRange, mHeight);     //由于上面是后摆放背景View,所以会覆盖前景View,因此需要通过下面的方式将前景View显示在前面     bringChildToFront(mFrontView);   }   /**    * 计算前景View的坐标    *    * @param isOpen 是否是打开前景View    * @return    */   private Rect computerFontViewRect(boolean isOpen) {     int left = isOpen ? -mRange : 0;     return new Rect(left, 0, left + mWidth, mHeight);   }   /**    * 打开侧边栏mBackView,默认平滑打开    */   public void open() {     open(true);   }   /**    * 打开侧边栏mBackView    *    * @param isSmooth 是否平滑打开    */   public void open(boolean isSmooth) {     if (isSmooth) {       if (mDragHelper.smoothSlideViewTo(mFrontView, -mRange, 0)) {         //动画在继续         ViewCompat.postInvalidateOnAnimation(this);       }     } else {       layoutChildView(true);     }   }   /**    * 关闭侧边栏mBackView,默认平滑关闭    */   public void close() {     close(true);   }   /**    * 关闭侧边栏mBackView    *    * @param isSmooth 是否平滑关闭    */   public void close(boolean isSmooth) {     if (isSmooth) {       if (mDragHelper.smoothSlideViewTo(mBackView, mWidth, 0)) {         //动画在继续         ViewCompat.postInvalidateOnAnimation(this);       }     } else {       layoutChildView(false);     }   }   @Override   public void computeScroll() {     super.computeScroll();     if (mDragHelper.continueSettling(true)) {       //动画还在继续       ViewCompat.postInvalidateOnAnimation(this);     }   } } 

<?xml version="1.0" encoding="utf-8"?> <mchenys.net.csdn.blog.myswipelayout.view.SwipeLayout    xmlns:android="http://schemas.android.com/apk/res/android"   android:id="@+id/sl"   android:layout_width="match_parent"   android:layout_height="60dp"   android:minHeight="60dp"   android:background="#44000000" >   <!--后置布局-->   <LinearLayout     android:layout_width="wrap_content"     android:layout_height="match_parent"     android:orientation="horizontal" >     <TextView       android:id="@+id/tv_call"       android:layout_width="60dp"       android:layout_height="match_parent"       android:background="#666666"       android:gravity="center"       android:text="Edit"       android:textColor="#ffffff" />     <TextView       android:id="@+id/tv_del"       android:layout_width="60dp"       android:layout_height="match_parent"       android:background="#ff0000"       android:gravity="center"       android:text="Delete"       android:textColor="#ffffff" />   </LinearLayout>   <!--前景布局-->   <LinearLayout     android:layout_width="match_parent"     android:layout_height="match_parent"     android:background="#44ffffff"     android:gravity="center_vertical"     android:orientation="horizontal" >     <ImageView       android:id="@+id/iv_image"       android:layout_width="40dp"       android:layout_height="40dp"       android:layout_marginLeft="15dp"       android:src="@drawable/head_1" />     <TextView       android:id="@+id/tv_name"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_marginLeft="15dp"       android:text="Name" />   </LinearLayout> </mchenys.net.csdn.blog.myswipelayout.view.SwipeLayout> 

/**  * 侧拉SwipeLayout的监听  * Created by mChenys on 2015/12/26.  */ public interface SwipeViewListener {   //关闭   void onClose(SwipeLayout mSwipeLayout);   //打开   void onOpen(SwipeLayout mSwipeLayout);   //正在侧拉   void onDraging(SwipeLayout mSwipeLayout);   //开始要去关闭   void onStartClose(SwipeLayout mSwipeLayout);   //开始要去开启   void onStartOpen(SwipeLayout mSwipeLayout); } 

//以下是定义SwipeLayout的打开,关闭,滑动的3种状态   public enum Status {     CLOSE, OPEN, DRAGING;   }   //默认关闭   private Status mStatus = Status.CLOSE;   //滑动的监听器   private SwipeViewListener mSwipeViewListener;   //设置监听器   public void setSwipeViewListener(SwipeViewListener swipeViewListener) {     mSwipeViewListener = swipeViewListener;   } 

/**    * 处理滑动,打开,关闭的3种情况    * 在onViewPositionChanged 调用    */   private void dispatchSwipeEvent() {     if (mSwipeViewListener != null) {       mSwipeViewListener.onDraging(this);     }     //记录上一次的状态     Status preStatus = mStatus;     //获取当前的状态     mStatus = getCurrStatus();     if (preStatus != mStatus && null != mSwipeViewListener) {       //说明有状态发生变化       if (mStatus == Status.CLOSE) {         //关闭         mSwipeViewListener.onClose(this);       } else if (mStatus == Status.OPEN) {         //打开         mSwipeViewListener.onOpen(this);       } else if (mStatus == Status.DRAGING) {         //这里有2中情况,要么要打开,要么要关闭         if (preStatus == Status.CLOSE) {           //如果之前是关闭的,那么就是要打开           mSwipeViewListener.onStartOpen(this);         } else if (preStatus == Status.OPEN) {           //如果之前是打开,那么就是要关闭           mSwipeViewListener.onStartClose(this);         }       }     }   }   /**    * 获取当前的状态    *    * @return    */   private Status getCurrStatus() {     int left = mFrontView.getLeft();     if (left == 0) {       return Status.CLOSE;     } else if (left == -mRange) {       return Status.OPEN;     }     return Status.DRAGING;   } 

public class MainActivity extends AppCompatActivity {   private List<String> mData = new ArrayList<>();//数据集合   @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     //获取数据,注意:Arrays.asList返回的并不是一个java.util.ArrayList，而是一个Arrays类的内部类，该List实现是不能进行增删操作的     //因此必须再包装一下     mData = new ArrayList<>(Arrays.asList(Constant.NAME));     ListView listView = new ListView(this);     listView.setAdapter(mAdapter);     setContentView(listView);   }   //自定义适配器   private BaseAdapter mAdapter = new BaseAdapter() {     //标记当前打开的SwipeLayout的集合     private List<SwipeLayout> mOpenItem = new ArrayList<>();     @Override     public int getCount() {       return mData.size();     }     @Override     public String getItem(int position) {       return mData.get(position);     }     @Override     public long getItemId(int position) {       return position;     }     @Override     public View getView(final int position, View convertView, ViewGroup parent) {       ViewHolder holder = null;       if (null == convertView) {         holder = new ViewHolder();         convertView = View.inflate(MainActivity.this, R.layout.item_list, null);         holder.mSwipeLayout = (SwipeLayout) convertView;         holder.tvName = (TextView) convertView.findViewById(R.id.tv_name);         holder.tvDel = (TextView) convertView.findViewById(R.id.tv_del);         holder.tvEdit = (TextView) convertView.findViewById(R.id.tv_edit);         convertView.setTag(holder);       } else {         holder = (ViewHolder) convertView.getTag();       }       //设置侧拉监听       holder.mSwipeLayout.setSwipeViewListener(getSwipeViewListener());       holder.tvName.setText(getItem(position));       holder.tvDel.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {           //删除           mData.remove(position);           mAdapter.notifyDataSetChanged();         }       });       holder.tvEdit.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {           ToastUtils.showToast(MainActivity.this,"编辑");         }       });       return convertView;     }     class ViewHolder {       TextView tvName, tvDel, tvEdit;       SwipeLayout mSwipeLayout;     }     //获取滑动监听器     private SwipeViewListener getSwipeViewListener() {       return new SwipeViewListener() {         @Override         public void onClose(SwipeLayout mSwipeLayout) {           //关闭是移除           mOpenItem.remove(mSwipeLayout);           ToastUtils.showToast(MainActivity.this, "关闭");         }         @Override         public void onOpen(SwipeLayout mSwipeLayout) {           //打开时添加           mOpenItem.add(mSwipeLayout);           ToastUtils.showToast(MainActivity.this, "打开");         }         @Override         public void onDraging(SwipeLayout mSwipeLayout) {         }         @Override         public void onStartClose(SwipeLayout mSwipeLayout) {           ToastUtils.showToast(MainActivity.this, "开始关闭");         }         @Override         public void onStartOpen(SwipeLayout mSwipeLayout) {           //将要打开时,需要将集合中的之前打开的SwipeLayout统统关闭           for (SwipeLayout swipeLayout : mOpenItem) {             swipeLayout.close();           }           mOpenItem.clear();//清空集合           ToastUtils.showToast(MainActivity.this, "开始打开");         }       };     }   }; }