package com.bear.swtichbuttondemo;
import java.util.ArrayList;
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;
/**
 * 自定义滑动开关
 */
public class MySwitchButton extends View implements OnTouchListener {
  private Bitmap switchOnBkg; // 开关开启时的背景
  private Bitmap switchOffBkg; // 开关关闭时的背景
  private Bitmap slipSwitchButton; // 滑动开关的图片
  private boolean isSlipping = false; // 是否正在滑动
  private boolean isSwitchOn = false; // 当前开关的状态，true表示开启，flase表示关闭
  private float previousX; // 手指按下时的水平坐标x
  private float currentX; // 当前的水平坐标X
  private ArrayList onSwitchListenerList; // 开关监听器列表
  public MySwitchButton(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }
  private void init() {
    this.setOnTouchListener(this); // 设置触摸监听器
    onSwitchListenerList = new ArrayList();
  }
  public void setImageResource(int switchBkg, int slipBtn) {
    switchOnBkg = BitmapFactory.decodeResource(this.getResources(),
        switchBkg);
    switchOffBkg = BitmapFactory.decodeResource(this.getResources(),
        switchBkg);
    slipSwitchButton = BitmapFactory.decodeResource(this.getResources(),
        slipBtn);
  }
  public void setSwitchState(boolean switchState) {
    this.isSwitchOn = switchState;
    this.invalidate();
  }
  public boolean getSwitchState() {
    return this.isSwitchOn;
  }
  public void setOnSwitchStateListener(OnSwitchListener listener){
    onSwitchListenerList.add(listener);
  }
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Matrix matrix = new Matrix();
    Paint paint = new Paint();
    float leftSlipBtnX; // 滑动按钮的左边坐标
    //画开关的背景图片
    canvas.drawBitmap(switchOnBkg, matrix, paint);
    if (isSlipping) {
      // 如果正在滑动
      if (currentX > switchOnBkg.getWidth()) {
        leftSlipBtnX = switchOnBkg.getWidth()
            - slipSwitchButton.getWidth();
      } else {
        leftSlipBtnX = currentX - slipSwitchButton.getWidth();
      }
    } else {
      //如果没有滑动
      if (isSwitchOn) {
        leftSlipBtnX = switchOnBkg.getWidth()
            - slipSwitchButton.getWidth();
      } else {
        leftSlipBtnX = 0;
      }
    }
    //如果手指滑出了开关的范围，应当这样处理
    if (leftSlipBtnX < 0) {
      leftSlipBtnX = 0;
    } else if (leftSlipBtnX > switchOnBkg.getWidth()
        - slipSwitchButton.getWidth()) {
      leftSlipBtnX = switchOnBkg.getWidth() - slipSwitchButton.getWidth();
    }
    //在画布上画开关图片
    canvas.drawBitmap(slipSwitchButton, leftSlipBtnX, 0, paint);
  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    setMeasuredDimension(switchOnBkg.getWidth(), switchOnBkg.getHeight());
  }
  @Override
  public boolean onTouch(View v, MotionEvent event) {
    //获取触摸动作类型
    int action = event.getAction();
    switch (action) {
    case MotionEvent.ACTION_MOVE:
      //如果现在处于手指一动状态
      currentX = event.getX();
      break;
    case MotionEvent.ACTION_DOWN:
      //如果现在手指刚刚按上屏幕状态
      isSlipping = true;
      break;
    case MotionEvent.ACTION_UP:
      //如果现在手指刚刚离开屏幕状态
      isSlipping = false;
      boolean previousState = isSwitchOn;
      if (event.getX() > (switchOnBkg.getWidth() / 2)) {
        isSwitchOn = true;
      } else {
        isSwitchOn = false;
      }
      //调用接口回调方法，将开关状态通知给监听对象
      if(previousState != isSwitchOn){
        if(onSwitchListenerList.size() > 0){
          for(OnSwitchListener listener : onSwitchListenerList){
            listener.onSwitched(isSwitchOn);
          }
        }
      }
      break;
    default:
      break;
    }
    this.invalidate();
    return true;
  }
}

package com.bear.swtichbuttondemo;
public interface OnSwitchListener {
  public abstract void onSwitched(boolean isSwitchOn);
}

package com.bear.swtichbuttondemo;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
  private MySwitchButton mySwitchButton;
  private Button myBtn;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    setupViews();
  }
  private void setupViews() {
    mySwitchButton = (MySwitchButton) findViewById(R.id.my_switch_button);
    //传图片给自定义组件
    mySwitchButton.setImageResource(R.drawable.switch_bkg_switch,
        R.drawable.switch_btn_slip);
    myBtn = (Button) findViewById(R.id.button);
    //设置开关状态监听
    mySwitchButton.setOnSwitchStateListener(new OnSwitchListener() {
      @Override
      public void onSwitched(boolean isSwitchOn) {
        if (isSwitchOn) {
          Toast.makeText(MainActivity.this, "开关开启",
              Toast.LENGTH_SHORT).show();
        } else {
          Toast.makeText(MainActivity.this, "开关关闭",
              Toast.LENGTH_SHORT).show();
        }
      }
    });
    myBtn.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        boolean isOn = mySwitchButton.getSwitchState();
        mySwitchButton.setSwitchState(!isOn);
      }
    });
  }
}