android 滑动按钮

package com.qing;

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

public class MySlipSwitch extends View implements OnTouchListener {

 //开关开启时的背景，关闭时的背景，滑动按钮
 private Bitmap switch_on_Bkg, switch_off_Bkg, slip_Btn;
 private Rect on_Rect, off_Rect;
 
 //是否正在滑动
 private boolean isSlipping = false;
 //当前开关状态，true为开启，false为关闭
 private boolean isSwitchOn = false;
 
 //手指按下时的水平坐标X，当前的水平坐标X
 private float previousX, currentX;
 
 //开关监听器
 private OnSwitchListener onSwitchListener;
 //是否设置了开关监听器
 private boolean isSwitchListenerOn = false;
 
 
 public MySlipSwitch(Context context) {
  super(context);
  init();
 }
 
 
 public MySlipSwitch(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }
 
 
 private void init() {
  setOnTouchListener(this);
 }
 
 
 protected void setImageResource(int switchOnBkg, int switchOffBkg, int slipBtn) {
  switch_on_Bkg = BitmapFactory.decodeResource(getResources(), switchOnBkg);
  switch_off_Bkg = BitmapFactory.decodeResource(getResources(), switchOffBkg);
  slip_Btn = BitmapFactory.decodeResource(getResources(), slipBtn); 
  
  //右半边Rect，即滑动按钮在右半边时表示开关开启
  on_Rect = new Rect(switch_off_Bkg.getWidth() - slip_Btn.getWidth(), 0, switch_off_Bkg.getWidth(), slip_Btn.getHeight());
  //左半边Rect，即滑动按钮在左半边时表示开关关闭
  off_Rect = new Rect(0, 0, slip_Btn.getWidth(), slip_Btn.getHeight());
 }
 
 
 protected void setSwitchState(boolean switchState) {
  isSwitchOn = switchState;
 }
 
 
 protected boolean getSwitchState() {
  return isSwitchOn;
 }
 
 
 protected void updateSwitchState(boolean switchState) {
  isSwitchOn = switchState;
  invalidate();
 }
 
 
 @Override
 protected void onDraw(Canvas canvas) {
  // TODO Auto-generated method stub
  super.onDraw(canvas);
  
  Matrix matrix = new Matrix();
  Paint paint = new Paint();
  //滑动按钮的左边坐标
  float left_SlipBtn;
  
  //手指滑动到左半边的时候表示开关为关闭状态，滑动到右半边的时候表示开关为开启状态
  if(currentX < (switch_on_Bkg.getWidth() / 2)) {
   canvas.drawBitmap(switch_off_Bkg, matrix, paint);
  } else {
   canvas.drawBitmap(switch_on_Bkg, matrix, paint);
  }
  
  //判断当前是否正在滑动
  if(isSlipping) {
   if(currentX > switch_on_Bkg.getWidth()) {
    left_SlipBtn = switch_on_Bkg.getWidth() - slip_Btn.getWidth();
   } else {
    left_SlipBtn = currentX - slip_Btn.getWidth() / 2;
   }
  } else {
   //根据当前的开关状态设置滑动按钮的位置
   if(isSwitchOn) {
    left_SlipBtn = on_Rect.left;
   } else {
    left_SlipBtn = off_Rect.left;
   }
  }
  
  //对滑动按钮的位置进行异常判断
  if(left_SlipBtn < 0) {
   left_SlipBtn = 0;
  } else if(left_SlipBtn > switch_on_Bkg.getWidth() - slip_Btn.getWidth()) {
   left_SlipBtn = switch_on_Bkg.getWidth() - slip_Btn.getWidth();
  }
  
  canvas.drawBitmap(slip_Btn, left_SlipBtn, 0, paint);
 }
 
 
 
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  // TODO Auto-generated method stub
  setMeasuredDimension(switch_on_Bkg.getWidth(), switch_on_Bkg.getHeight());
 }

 @Override
 public boolean onTouch(View v, MotionEvent event) {
  // TODO Auto-generated method stub
  switch(event.getAction()) {
  //滑动
  case MotionEvent.ACTION_MOVE:
   currentX = event.getX();
   break;
   
  //按下
  case MotionEvent.ACTION_DOWN:
   if(event.getX() > switch_on_Bkg.getWidth() || event.getY() > switch_on_Bkg.getHeight()) {
    return false;
   }
   
   isSlipping = true;
   previousX = event.getX();
   currentX = previousX;
   break;
  
  //松开
  case MotionEvent.ACTION_UP:
   isSlipping = false;
   //松开前开关的状态
   boolean previousSwitchState  = isSwitchOn;
   
   if(event.getX() >= (switch_on_Bkg.getWidth() / 2)) {
    isSwitchOn = true;
   } else {
    isSwitchOn = false;
   }
   
   //如果设置了监听器，则调用此方法
   if(isSwitchListenerOn && (previousSwitchState != isSwitchOn)) {
    onSwitchListener.onSwitched(isSwitchOn);
   }
   break;
  
  default:
   break;
  }
  
  //重新绘制控件
  invalidate();
  return true;
 }

 public void setOnSwitchListener(OnSwitchListener listener) {
  onSwitchListener = listener;
  isSwitchListenerOn = true;
 }
 
 
 public interface OnSwitchListener {
  abstract void onSwitched(boolean isSwitchOn);
 }
}

 

调用

 slipswitch_MSL = (MySlipSwitch)findViewById(R.id.main_myslipswitch);
        slipswitch_MSL.setImageResource(R.drawable.bkg_switch, R.drawable.bkg_switch, R.drawable.btn_slip);
        slipswitch_MSL.setSwitchState(true);
        slipswitch_MSL.setOnSwitchListener(new OnSwitchListener() {
   
   @Override
   public void onSwitched(boolean isSwitchOn) {
    // TODO Auto-generated method stub
    if(isSwitchOn) {
     Toast.makeText(MainActivity.this, "开关已经开启", 300).show();
    } else {
     Toast.makeText(MainActivity.this, "开关已经关闭", 300).show();
    }
   }
  });