Android仿QQ左滑删除置顶ListView操作

最近闲来无事，于是研究了一下qq的左滑删除效果，尝试着实现了一下，先上效果图：

大致思路原理：
- 通过设置margin实现菜单的显示与隐藏
- 监听onTouchEvent，处理滑动事件

上代码

import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.ListView;

/**
 * Created by MooreLi on 2016/8/8.
 */
public class SlideListView extends ListView {
  private String TAG = getClass().getSimpleName();

  private int mScreenWidth;
  private int mDownX;
  private int mDownY;
  private int mMenuWidth;

  private boolean isMenuShow;
  private boolean isMoving;

  private int mOperatePosition = -1;
  private ViewGroup mPointChild;
  private LinearLayout.LayoutParams mLayoutParams;

  public SlideListView(Context context) {
    super(context);
    getScreenWidth(context);
  }

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

  public SlideListView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    getScreenWidth(context);
  }

  private void getScreenWidth(Context context) {
    WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    DisplayMetrics dm = new DisplayMetrics();
    manager.getDefaultDisplay().getMetrics(dm);
    mScreenWidth = dm.widthPixels;
  }

  @Override
  public boolean onTouchEvent(MotionEvent ev) {
    switch (ev.getAction()) {
      case MotionEvent.ACTION_DOWN:
        performActionDown(ev);
        break;
      case MotionEvent.ACTION_MOVE:
        performActionMove(ev);
        break;
      case MotionEvent.ACTION_UP:
        performActionUp();
        break;
    }
    return super.onTouchEvent(ev);
  }

  private void performActionDown(MotionEvent ev) {
    mDownX = (int) ev.getX();
    mDownY = (int) ev.getY();
    //如果点击的不是同一个item，则关掉正在显示的菜单
    int position = pointToPosition(mDownX, mDownY);
    if (isMenuShow && position != mOperatePosition) {
      turnToNormal();
    }
    mOperatePosition = position;
    mPointChild = (ViewGroup) getChildAt(position - getFirstVisiblePosition());
    if (mPointChild != null) {
      mMenuWidth = mPointChild.getChildAt(1).getLayoutParams().width;
      mLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0).getLayoutParams();
      mLayoutParams.width = mScreenWidth;
      setChildLayoutParams();
    }
  }

  private boolean performActionMove(MotionEvent ev) {
    int nowX = (int) ev.getX();
    int nowY = (int) ev.getY();
//    if (isMoving) {
//      if (Math.abs(nowY - mDownY) > 0) {
//        Log.e(TAG, "kkkkkkk");
//        onInterceptTouchEvent(ev);
//      }
//    }
    if (Math.abs(nowX - mDownX) > 0) {
      //左滑 显示菜单
      if (nowX < mDownX) {
        if (isMenuShow) {
          mLayoutParams.leftMargin = -mMenuWidth;
        } else {
          //计算显示的宽度
          int scroll = (nowX - mDownX);
          if (-scroll >= mMenuWidth) {
            scroll = -mMenuWidth;
          }
          mLayoutParams.leftMargin = scroll;
        }
      }
      //右滑 如果菜单显示状态，则关闭菜单
      if (isMenuShow && nowX > mDownX) {
        int scroll = nowX - mDownX;
        if (scroll >= mMenuWidth) {
          scroll = mMenuWidth;
        }
        mLayoutParams.leftMargin = scroll - mMenuWidth;
      }
      setChildLayoutParams();
      isMoving = true;
      return true;
    }

    return super.onTouchEvent(ev);
  }

  private void performActionUp() {
    //超过一半时，显示菜单，否则隐藏
    if (-mLayoutParams.leftMargin >= mMenuWidth / 2) {
      mLayoutParams.leftMargin = -mMenuWidth;
      setChildLayoutParams();
      isMenuShow = true;
    } else {
      turnToNormal();
    }
    isMoving = false;
  }

  private void setChildLayoutParams(){
    if(mPointChild != null){
      mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
    }
  }

  /**
   * 正常显示
   */
  public void turnToNormal() {
    mLayoutParams.leftMargin = 0;
    mOperatePosition = -1;
    setChildLayoutParams();
    isMenuShow = false;
  }
}

item的布局要注意，因为在自定义view中写死的是获取第一个子布局为显示内容，所以需要将显示的样式写在一个容器中，将菜单写在另一个容器中，两个平行的关系。
xml文件定义如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="#FFFFFF"
  android:orientation="horizontal">

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:orientation="horizontal">

    <TextView
      android:id="@+id/main_tv_title"
      android:layout_width="wrap_content"
      android:layout_height="match_parent"
      android:layout_marginLeft="10dp"
      android:gravity="center_vertical"
      android:textSize="18sp" />
  </LinearLayout>

  <LinearLayout
    android:layout_width="180dp"
    android:layout_height="60dp"
    android:orientation="horizontal">

    <TextView
      android:id="@+id/main_tv_delete"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1"
      android:background="#FF0000"
      android:gravity="center"
      android:text="删除"
      android:textColor="#FFFFFF" />

    <TextView
      android:id="@+id/main_tv_top"
      android:layout_width="0dp"
      android:layout_height="match_parent"
      android:layout_weight="1"
      android:background="#DFCDBF"
      android:gravity="center"
      android:text="置顶"
      android:textColor="#FFFFFF" />
  </LinearLayout>
</LinearLayout>

最后就是删除操作与置顶操作，这个就比较简单，给按钮添加点击事件即可。我是在adapter中定义实现，记得操作后要将菜单关掉！

上部分代码：

    holder.tvTitle.setText(mInfos.get(position));
    holder.tvDelete.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        mInfos.remove(position);
        notifyDataSetChanged();
        mListView.turnToNormal();
      }
    });
    holder.tvTop.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        String temp = mInfos.get(position);
        mInfos.remove(position);
        mInfos.add(0, temp);
        notifyDataSetChanged();
        mListView.turnToNormal();
      }
    });

最后还有一个遗留问题，ListView左右滑动的时候上下也会滑动，这个有待探索与改进，也希望大家提提意见，帮我改进！

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