package com.example.drawkongjian;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

/**
 * Created by John on 2018/5/12 0012.
 */

public class MyWanChen extends View implements View.OnClickListener {

    private Paint paint;
    private Bitmap sbackground;
    private Bitmap sbutton;
    private int bgwidth;
    private int bgheight;

    //定义变量
    private boolean isOpen = false;
    private boolean isMove = false;
    private int xzhou = 0;//定义x轴位置
    private int firstX;//用户滑动的开始位置
    private int lastX;//用户滑动的结束位置
    private int xzhouMax;

    //2.声明接口对象
    private IcallBack icallBack;

    //3.获取接口对象中的方法
    public void setIcallBack(IcallBack icallBack){
        this.icallBack = icallBack;
    }
    //1.定义接口
    public interface IcallBack{
        //只有申明，没有实现
        void onClickOpen(boolean isOpnes);
    }


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

    public MyWanChen(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs,0);
    }

    public MyWanChen(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView();
    }

    private void initView() {
        //得到两张图片
        sbackground = BitmapFactory.decodeResource(getResources(), R.drawable.switch_background);
        sbutton = BitmapFactory.decodeResource(getResources(), R.drawable.slide_button);
        //创建画笔
        paint = new Paint();
        //获取背景图的一半
        xzhouMax = sbackground.getWidth()-sbutton.getWidth();
        setOnClickListener(this);
    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        bgwidth = sbackground.getWidth();
        bgheight = sbackground.getHeight();
        setMeasuredDimension(bgwidth,bgheight);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawBitmap(sbackground,0,0,paint);
        canvas.drawBitmap(sbutton,xzhou,0,paint);
    }

    @Override
    public void onClick(View view) {
        if(!isMove){
            if(isOpen){
                xzhou = 0;
            }else {
                xzhou = xzhouMax;
            }
            isOpen = !isOpen;//去反值
            icallBack.onClickOpen(isOpen);//给接口中的方法赋值
        }

        invalidate();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        super.onTouchEvent(event);
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                //获取移动开始的位置
                lastX = firstX = (int) event.getX();
                isMove = false; //不是移动
                break;
            case MotionEvent.ACTION_MOVE:
                //获取用的新坐标
                int newX = (int) event.getX();
                //移动的长度为  新坐标-获取移动开始的位置
                int yidong = newX-lastX;
                int abs = Math.abs(yidong);//跟移动的位置判断他是移动还是点击
                if(abs > 4){
                    isMove = true;
                    Toast.makeText(getContext(), "你好我是移动", Toast.LENGTH_SHORT).show();
                }
                xzhou = xzhou+yidong;
                lastX = newX;//最新的x轴坐标就成了新的终点
                //调用方法
                setKuan();
                break;
            case MotionEvent.ACTION_UP:
                //获得抬起时的坐标
                int upX = (int) event.getX();
                if(upX - firstX > xzhouMax/2){
                    isOpen = true;
                }else if(firstX - upX >xzhouMax/2){
                    isOpen = false;
                }
                gaiBiaoZhuangTai();
                break;
        }
        return true;
    }

    private void gaiBiaoZhuangTai() {
        if(isOpen){
            xzhou = xzhouMax;
        }else {
            xzhou = 0;
        }
    }


    private void setKuan() {
        if(xzhou<0){
            xzhou = 0;
        }else if(xzhou>xzhouMax){
            xzhou = xzhouMax;
        }
        invalidate();
    }


}

-----------------布局页面----------------------

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.drawkongjian.MainActivity">

    <com.example.drawkongjian.MyWanChen
        android:id="@+id/mywc"
        android:layout_below="@+id/jkjk"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>

----------------------主类----------------

package com.example.drawkongjian;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        /*MyView myView = new MyView(this);
        MyOpen open = new MyOpen(this);*/
        MyWanChen myWanChen = findViewById(R.id.mywc);
        myWanChen.setIcallBack(new MyWanChen.IcallBack() {//接口的回调
            @Override
            public void onClickOpen(boolean isOpnes) {
                Toast.makeText(MainActivity.this, ""+isOpnes, Toast.LENGTH_SHORT).show();
            }
        });
    }
}