Android SwitchButton 完善版（在前人基础上完善）

import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Paint.Style;import android.graphics.Path;import android.graphics.RadialGradient;import android.graphics.RectF;import android.graphics.Shader;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.animation.AccelerateInterpolator;public class SwitchView extends View{   private final Paint paint = new Paint();   private final Path sPath = new Path();   private final Path bPath = new Path();   private final RectF bRectF = new RectF();   private float sAnim, bAnim;   private RadialGradient shadowGradient;   private final AccelerateInterpolator aInterpolator = new AccelerateInterpolator(2);   /**    * state switch on    */   public static final int STATE_SWITCH_ON = 4;   /**    * state prepare to off    */   public static final int STATE_SWITCH_ON2 = 3;   /**    * state prepare to on    */   public static final int STATE_SWITCH_OFF2 = 2;   /**    * state prepare to off    */   public static final int STATE_SWITCH_OFF = 1;   /**    * current state    */   private int state = STATE_SWITCH_OFF;   /**    * last state    */   private int lastState = state;   private int mWidth, mHeight;   private float sWidth, sHeight;   private float sLeft, sTop, sRight, sBottom;   private float sCenterX, sCenterY;   private float sScale;   private float bOffset;   private float bRadius, bStrokeWidth;   private float bWidth;   private float bLeft, bTop, bRight, bBottom;   private float bOnLeftX, bOn2LeftX, bOff2LeftX, bOffLeftX;   private float shadowHeight;   int  xFirst=0;   public SwitchView(Context context) {      this(context, null);   }   public SwitchView(Context context, AttributeSet attrs) {      super(context, attrs);      setLayerType(LAYER_TYPE_SOFTWARE, null);   }   @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {      int widthSize = MeasureSpec.getSize(widthMeasureSpec);      int heightSize = (int) (widthSize * 0.65f);      setMeasuredDimension(widthSize, heightSize);   }   @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {      super.onSizeChanged(w, h, oldw, oldh);      mWidth = w;      mHeight = h;      sLeft = sTop = 0;      sRight = mWidth;      sBottom = mHeight * 0.91f;      sWidth = sRight - sLeft;      sHeight = sBottom - sTop;      sCenterX = (sRight + sLeft) / 2;      sCenterY = (sBottom + sTop) / 2;      shadowHeight = mHeight - sBottom;      bLeft = bTop = 0;      bRight = bBottom = sBottom;      bWidth = bRight - bLeft;      final float halfHeightOfS = (sBottom - sTop) / 2;      bRadius = halfHeightOfS * 0.95f;      bOffset = bRadius * 0.2f;      bStrokeWidth = (halfHeightOfS - bRadius) * 2;      bOnLeftX = sWidth - bWidth;      bOn2LeftX = bOnLeftX - bOffset;      bOffLeftX = 0;      bOff2LeftX = 0;      sScale = 1 - bStrokeWidth / sHeight;      RectF sRectF = new RectF(sLeft, sTop, sBottom, sBottom);      sPath.arcTo(sRectF, 90, 180);      sRectF.left = sRight - sBottom;      sRectF.right = sRight;      sPath.arcTo(sRectF, 270, 180);      sPath.close();      bRectF.left = bLeft;      bRectF.right = bRight;      bRectF.top = bTop + bStrokeWidth / 2;      bRectF.bottom = bBottom - bStrokeWidth / 2;      shadowGradient = new RadialGradient(bWidth / 2, bWidth / 2, bWidth / 2, 0xff000000, 0x00000000, Shader.TileMode.CLAMP);   }   private void calcBPath(float percent) {      bPath.reset();      bRectF.left = bLeft + bStrokeWidth / 2;      bRectF.right = bRight - bStrokeWidth / 2;      bPath.arcTo(bRectF, 90, 180);      bRectF.left = bLeft + percent * bOffset + bStrokeWidth / 2;      bRectF.right = bRight + percent * bOffset - bStrokeWidth / 2;      bPath.arcTo(bRectF, 270, 180);      bPath.close();   }   private float calcBTranslate(float percent) {      float result = 0;      int wich = state - lastState;      switch (wich) {         case 1:            // off -> off2            if (state == STATE_SWITCH_OFF2) {               result = bOff2LeftX - (bOff2LeftX - bOffLeftX) * percent;            }            // on2 -> on            else if (state == STATE_SWITCH_ON) {               result = bOnLeftX - (bOnLeftX - bOn2LeftX) * percent;            }            break;         case 2:            // off2 -> on            if (state == STATE_SWITCH_ON) {               result = bOnLeftX - (bOnLeftX - bOff2LeftX) * percent;            }            // off -> on2            else if (state == STATE_SWITCH_ON) {               result = bOn2LeftX - (bOn2LeftX - bOffLeftX) * percent;            }            break;         case 3: // off -> on            result = bOnLeftX - (bOnLeftX - bOffLeftX) * percent;            break;         case -1:            // on -> on2            if (state == STATE_SWITCH_ON2) {               result = bOn2LeftX + (bOnLeftX - bOn2LeftX) * percent;            }            // off2 -> off            else if (state == STATE_SWITCH_OFF) {               result = bOffLeftX + (bOff2LeftX - bOffLeftX) * percent;            }            break;         case -2:            // on2 -> off            if (state == STATE_SWITCH_OFF) {               result = bOffLeftX + (bOn2LeftX - bOffLeftX) * percent;            }            // on -> off2            else if (state == STATE_SWITCH_OFF2) {               result = bOff2LeftX + (bOnLeftX - bOff2LeftX) * percent;            }            break;         case -3: // on -> off            result = bOffLeftX + (bOnLeftX - bOffLeftX) * percent;            break;      }      return result - bOffLeftX;   }   @Override protected void onDraw(Canvas canvas) {      super.onDraw(canvas);      paint.setAntiAlias(true);      final boolean isOn = (state == STATE_SWITCH_ON || state == STATE_SWITCH_ON2);      // draw background      paint.setStyle(Style.FILL);      paint.setColor(isOn ? 0xff4bd763 : 0xffe3e3e3);      canvas.drawPath(sPath, paint);      sAnim = sAnim - 0.1f > 0 ? sAnim - 0.1f : 0;      bAnim = bAnim - 0.1f > 0 ? bAnim - 0.1f : 0;      final float dsAnim = aInterpolator.getInterpolation(sAnim);      final float dbAnim = aInterpolator.getInterpolation(bAnim);      // draw background animation      final float scale = sScale * (isOn ? dsAnim : 1 - dsAnim);      final float scaleOffset = (bOnLeftX + bRadius - sCenterX) * (isOn ? 1 - dsAnim : dsAnim);      canvas.save();      canvas.scale(scale, scale, sCenterX + scaleOffset, sCenterY);      paint.setColor(0xffffffff);      canvas.drawPath(sPath, paint);      canvas.restore();      // draw center bar      canvas.save();      canvas.translate(calcBTranslate(dbAnim), shadowHeight);      final boolean isState2 = (state == STATE_SWITCH_ON2 || state == STATE_SWITCH_OFF2);      calcBPath(isState2 ? 1 - dbAnim : dbAnim);      // draw shadow      paint.setStyle(Style.FILL);      paint.setColor(0xff333333);      paint.setShader(shadowGradient);      canvas.drawPath(bPath, paint);      paint.setShader(null);      canvas.translate(0, -shadowHeight);      canvas.scale(0.98f, 0.98f, bWidth / 2, bWidth / 2);      paint.setStyle(Style.FILL);      paint.setColor(0xffffffff);      canvas.drawPath(bPath, paint);      paint.setStyle(Style.STROKE);      paint.setStrokeWidth(bStrokeWidth * 0.5f);      paint.setColor(isOn ? 0xff4ada60 : 0xffbfbfbf);      canvas.drawPath(bPath, paint);      canvas.restore();      paint.reset();      if (sAnim > 0 || bAnim > 0) invalidate();   }   @Override public boolean onTouchEvent(MotionEvent event) {      if ((state == STATE_SWITCH_ON || state == STATE_SWITCH_OFF) && (sAnim * bAnim == 0)) {         switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:               xFirst =(int)event.getRawX();               return true;            case MotionEvent.ACTION_CANCEL:            case MotionEvent.ACTION_UP:               int  xSecond=(int)event.getRawX();               int  distance=xSecond-xFirst;               lastState = state;                   if(distance==0) {                  if (state == STATE_SWITCH_OFF) {                     refreshState(STATE_SWITCH_OFF2);                     actionSwitch();                  } else if (state == STATE_SWITCH_ON) {                     refreshState(STATE_SWITCH_ON2);                     actionSwitch();                  }               }               //????               if(distance>0){                  if (state == STATE_SWITCH_OFF) {                     refreshState(STATE_SWITCH_OFF2);                     actionSwitch();                  }               }                    //????               if(distance<0){                   if (state == STATE_SWITCH_ON) {                     refreshState(STATE_SWITCH_ON2);                      actionSwitch();                  }               }               break;         }      }      return  super.onTouchEvent(event);   }private void actionSwitch(){   if (listener != null) {      if (state == STATE_SWITCH_OFF2 ) {         listener.toggleToOn();      }      else if (state == STATE_SWITCH_ON2) {         listener.toggleToOff();      }   }}   private void refreshState(int newState) {      lastState = state;      state = newState;      postInvalidate();      bAnim = 1;      invalidate();   }   /**    *    * @return the state of switch view    */   public int getState() {      return state;   }   /**    * if set true , the state change to on;    * if set false, the state change to off    * @param isOn    */   public void setState(boolean isOn) {      final int wich = isOn ? STATE_SWITCH_ON : STATE_SWITCH_OFF;      if(state!=wich) {         refreshState(wich);      }   }   /**    * if set true , the state change to on;    * if set false, the state change to off    * <br><b>change state with animation</b>    * @param letItOn    */   public void toggleSwitch(boolean letItOn) {      final int wich = letItOn ? STATE_SWITCH_ON : STATE_SWITCH_OFF;      postDelayed(new Runnable() {         @Override         public void run() {            toggleSwitch(wich);         }      }, 100);   }   private synchronized void toggleSwitch(int wich) {      if (wich == STATE_SWITCH_ON || wich == STATE_SWITCH_OFF) {         if ((wich == STATE_SWITCH_ON && (lastState == STATE_SWITCH_OFF || lastState == STATE_SWITCH_OFF2))               || (wich == STATE_SWITCH_OFF && (lastState == STATE_SWITCH_ON || lastState == STATE_SWITCH_ON2))) {            sAnim = 1;         }         bAnim = 1;         refreshState(wich);      }   }   public interface OnStateChangedListener {      void toggleToOn();      void toggleToOff();   }   private OnStateChangedListener listener = new OnStateChangedListener() {      @Override public void toggleToOn() {         toggleSwitch(STATE_SWITCH_ON);      }      @Override public void toggleToOff() {         toggleSwitch(STATE_SWITCH_OFF);      }   };   public void setOnStateChangedListener(OnStateChangedListener listener) {      if (listener == null) throw new IllegalArgumentException("empty listener");      this.listener = listener;   }}