android自定义滑动选择开关

package com.yuntongxun.ecdemo.common.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import com.yuntongxun.ecdemo.R;

/**  * Created by yangyang on 4/7/16.  * 滑动开关按钮  */ public class SwitchButton extends View implements View.OnClickListener{

    private Bitmap switchgreen,switchbottom,switchbutton;
    private Boolean state=true;
    private float mcurrentx=0,mlastx=0,dexs=0,countx=0;//当前位置,最后一次位置,移动距离  private OnChangeListener mlistener;
    private Paint paint;


    public SwitchButton(Context context) {
       this(context,null);
    }
    public SwitchButton(Context context, AttributeSet attrs) {
        this(context, null, 0);
    }
    public SwitchButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public Boolean getState() {
        return state;
    }

    public void setState(Boolean state) {
        this.state = state;
    }

    public void init(){

        switchbottom= BitmapFactory.decodeResource(getResources(), R.drawable.switchbottom);
        switchbutton=BitmapFactory.decodeResource(getResources(), R.drawable.switchbutton);
        switchgreen=BitmapFactory.decodeResource(getResources(), R.drawable.switchgreen);
        countx=switchbottom.getWidth()-switchbutton.getWidth();
        setOnClickListener(this);
        setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return false;
            }
        });

        paint=new Paint();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec,int heightMeasureSpec){
        setMeasuredDimension(switchbottom.getWidth(), switchbottom.getHeight());
    }
    @Override
    protected void onDraw(Canvas canvas){
        if(state){
            canvas.drawBitmap(switchgreen,0,0,null);
           canvas.drawBitmap(switchbutton,0,0,null);
        }else {
            canvas.drawBitmap(switchbottom,0,0,null);
            canvas.drawBitmap(switchbutton, countx, 0,null);
        }

    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                mlastx=event.getX();
            case MotionEvent.ACTION_MOVE:
                mcurrentx=event.getX();
                dexs=mcurrentx-mlastx;
                dexs+=dexs;

                invalidate();
                //return true;  case MotionEvent.ACTION_UP:
               if(Math.abs(dexs)>switchbottom.getWidth()/2){
                   state=!state;
               }
                    invalidate();

            default:
                break;

        }
        invalidate();

        return super.onTouchEvent(event);
    }

    @Override
    public void onClick(View v) {
        //countx = state ?switchbottom.getWidth() - switchbutton.getWidth() : 0;  state = !state;
        if(mlistener != null) {
           mlistener.OnChange(this,state);
        }
        invalidate();
    }
    public void setOnChangeListener(OnChangeListener listener){
        mlistener=listener;
    }

    public interface OnChangeListener {
        public void OnChange(SwitchButton sb, Boolean state);
    }

}