ListView左划删除

参考网上大神的例子，自己照着大意写了一遍（留着参考，方便日后使用）

1、新建MyListView 继承自ListView 重写方法

代码如下：

package com.deletetest;
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 Administrator on 2016/12/9.
 */
public class MyListView extends ListView {
    private int mScreenWidth; // 屏幕宽度
    private int mDownX; // 按下点的x值
    private int mDownY; // 按下点的y值
    private int mDeleteBtnWidth;// 删除按钮的宽度
    private boolean isDeleteShown; // 删除按钮是否正在显示
    private ViewGroup mPointChild; // 当前处理的item
    private LinearLayout.LayoutParams mLayoutParams;// 当前处理的item的LayoutParams
    public MyListView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }
    public MyListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // 获取屏幕宽度
        WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics dm = new DisplayMetrics();
        wm.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:
                return performActionMove(ev);
            case MotionEvent.ACTION_UP:
                performActionUp();
                break;
        }
        return super.onTouchEvent(ev);
    }

    // 处理action_down事件
    private void performActionDown(MotionEvent ev) {
        if(isDeleteShown) {
            turnToNormal();
        }
        mDownX = (int) ev.getX();
        mDownY = (int) ev.getY();
        // 获取当前点的item
        mPointChild = (ViewGroup) getChildAt(pointToPosition(mDownX, mDownY)
                - getFirstVisiblePosition());
        // 获取删除按钮的宽度
        mDeleteBtnWidth = mPointChild.getChildAt(1).getLayoutParams().width;
        mLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0)
                .getLayoutParams();
        // 为什么要重新设置layout_width 等于屏幕宽度
        // 因为match_parent时，不管你怎么滑，都不会显示删除按钮
        // why？ 因为match_parent时，ViewGroup就不去布局剩下的view
        mLayoutParams.width = mScreenWidth;
        mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
    }


    // 处理action_move事件
    private boolean performActionMove(MotionEvent ev) {
        int nowX = (int) ev.getX();
        int nowY = (int) ev.getY();
        if(Math.abs(nowX - mDownX) > Math.abs(nowY - mDownY)) {
            // 如果向左滑动
            if(nowX < mDownX) {
                // 计算要偏移的距离
                int scroll = (nowX - mDownX) / 3;
                // 如果大于了删除按钮的宽度， 则最大为删除按钮的宽度
                if(-scroll >= mDeleteBtnWidth) {
                    scroll = -mDeleteBtnWidth;
                }
                // 重新设置leftMargin
                mLayoutParams.leftMargin = scroll;
                mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
            }
            return true;
        }
        return super.onTouchEvent(ev);
    }
    // 处理action_up事件
    private void performActionUp() {
        // 偏移量大于button的一半，则显示button
        // 否则恢复默认
        if(-mLayoutParams.leftMargin >= mDeleteBtnWidth / 3) {
            mLayoutParams.leftMargin = -mDeleteBtnWidth;
            isDeleteShown = true;
        }else {
            turnToNormal();
        }
        mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
    }
    /**
     * 变为正常状态
     */
    public void turnToNormal() {
        mLayoutParams.leftMargin = 0;
        mPointChild.getChildAt(0).setLayoutParams(mLayoutParams);
        isDeleteShown = false;
    }
    /**
     * 当前是否可点击
     * @return 是否可点击
     */
    public boolean canClick() {
        return !isDeleteShown;
    }

}

2、activity侧代码：

package com.deletetest;


import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
    private MyListView mListView;
    private ArrayList<String> mData = new ArrayList<String>() {
        {
            for(int i=0;i<50;i++) {
                add("十言" + i);
            }
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView = (MyListView) findViewById(R.id.list);
        mListView.setAdapter(new MyAdapter());
        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                if(mListView.canClick()) {
                    Toast.makeText(MainActivity.this, mData.get(position), Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

    class MyAdapter extends BaseAdapter {
        @Override
        public int getCount() {
            return mData.size();
        }


        @Override
        public Object getItem(int position) {
            return mData.get(position);
        }


        @Override
        public long getItemId(int position) {
            return position;
        }


        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            if(null == convertView) {
                convertView = View.inflate(MainActivity.this, R.layout.item, null);
            }
            TextView tv = (TextView) convertView.findViewById(R.id.tv);
            TextView delete = (TextView) convertView.findViewById(R.id.delete);
            tv.setText(mData.get(position));
            final int pos = position;
            delete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mData.remove(pos);
                    notifyDataSetChanged();
                    mListView.turnToNormal();
                    Toast.makeText(MainActivity.this,"已删除",Toast.LENGTH_SHORT).show();
                }
            });


            return convertView;
        }
    }
}

3、activity侧布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.deletetest.MainActivity">


    <com.loupai.deletetest.MyListView
        android:id="@+id/list"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:cacheColorHint="@android:color/transparent"
        android:listSelector="@android:color/transparent"
        android:divider="@android:color/darker_gray"
        android:dividerHeight="2dp"
        android:scrollbars="none"/>
</RelativeLayout>

4、item布局如下

<?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:orientation="horizontal">


    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingBottom="20dp"
        android:paddingLeft="10dp"
        android:paddingTop="20dp"
        android:background="@android:color/white"/>
    <TextView
        android:id="@+id/delete"
        android:layout_width="100dp"
        android:layout_height="match_parent"
        android:background="#FFFF0000"
        android:gravity="center"
        android:textColor="@android:color/white"
        android:paddingRight="20dp"
        android:text="删除" />

</LinearLayout>