Android 实现旋转木马的音乐效果

<span style="font-size:18px;">public class MainActivity extends Activity {  MediaPlayer m1;  ImageView infoOperatingIV;   @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    infoOperatingIV = (ImageView) findViewById(R.id.infoOperating);     Button play = (Button) findViewById(R.id.play);    Button stop = (Button) findViewById(R.id.stop);     play.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        playMusic();      }    });     stop.setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        stopMusic();      }    });   }   private void playMusic() {    m1 = MediaPlayer.create(this, R.raw.quiet);    m1.start();     Animation operatingAnim = AnimationUtils.loadAnimation(this, R.anim.tip);    LinearInterpolator lin = new LinearInterpolator();    operatingAnim.setInterpolator(lin);    if (operatingAnim != null) {      infoOperatingIV.startAnimation(operatingAnim);    }     m1.setOnCompletionListener(new OnCompletionListener() {      @Override      public void onCompletion(MediaPlayer mp) {        mp.stop();        infoOperatingIV.clearAnimation();      }    });  }   private void stopMusic() {    m1.stop();    infoOperatingIV.clearAnimation();  } }</span><span style="font-size: 16pt;"></span>

  <span style="font-size:18px;">public class RoundImageView extends ImageView {  private int mBorderThickness = 0;  private Context mContext;  private int defaultColor = 0xFFFFFFFF;  // 如果只有其中一个有值，则只画一个圆形边框  private int mBorderOutsideColor = 0;  private int mBorderInsideColor = 0;  // 控件默认长、宽  private int defaultWidth = 0;  private int defaultHeight = 0;   public RoundImageView(Context context) {    super(context);    mContext = context;  }   public RoundImageView(Context context, AttributeSet attrs) {    super(context, attrs);    mContext = context;    setCustomAttributes(attrs);  }   public RoundImageView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);    mContext = context;    setCustomAttributes(attrs);  }   private void setCustomAttributes(AttributeSet attrs) {    TypedArray a = mContext.obtainStyledAttributes(attrs, R.styleable.roundedimageview);    mBorderThickness = a.getDimensionPixelSize(R.styleable.roundedimageview_border_thickness, 0);    mBorderOutsideColor = a.getColor(R.styleable.roundedimageview_border_outside_color, defaultColor);    mBorderInsideColor = a.getColor(R.styleable.roundedimageview_border_inside_color, defaultColor);  }   @Override  protected void onDraw(Canvas canvas) {    Drawable drawable = getDrawable();    if (drawable == null) {      return;    }     if (getWidth() == 0 || getHeight() == 0) {      return;    }    this.measure(0, 0);    if (drawable.getClass() == NinePatchDrawable.class)      return;    Bitmap b = ((BitmapDrawable) drawable).getBitmap();    Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);    if (defaultWidth == 0) {      defaultWidth = getWidth();     }    if (defaultHeight == 0) {      defaultHeight = getHeight();    }    // 保证重新读取图片后不会因为图片大小而改变控件宽、高的大小（针对宽、高为wrap_content布局的imageview，但会导致margin无效）    // if (defaultWidth != 0 && defaultHeight != 0) {    // LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(    // defaultWidth, defaultHeight);    // setLayoutParams(params);    // }    int radius = 0;    if (mBorderInsideColor != defaultColor && mBorderOutsideColor != defaultColor) {// 定义画两个边框，分别为外圆边框和内圆边框      radius = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / 2 - 2 * mBorderThickness;      // 画内圆      drawCircleBorder(canvas, radius + mBorderThickness / 2, mBorderInsideColor);      // 画外圆      drawCircleBorder(canvas, radius + mBorderThickness + mBorderThickness / 2, mBorderOutsideColor);    } else if (mBorderInsideColor != defaultColor && mBorderOutsideColor == defaultColor) {// 定义画一个边框      radius = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / 2 - mBorderThickness;      drawCircleBorder(canvas, radius + mBorderThickness / 2, mBorderInsideColor);    } else if (mBorderInsideColor == defaultColor && mBorderOutsideColor != defaultColor) {// 定义画一个边框      radius = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / 2 - mBorderThickness;      drawCircleBorder(canvas, radius + mBorderThickness / 2, mBorderOutsideColor);    } else {// 没有边框      radius = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / 2;    }    Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);    canvas.drawBitmap(roundBitmap, defaultWidth / 2 - radius, defaultHeight / 2 - radius, null);  }   /**   * 获取裁剪后的圆形图片   *   * @param radius   *      半径   */  public Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius) {    Bitmap scaledSrcBmp;    int diameter = radius * 2;     // 为了防止宽高不相等，造成圆形图片变形，因此截取长方形中处于中间位置最大的正方形图片    int bmpWidth = bmp.getWidth();    int bmpHeight = bmp.getHeight();    int squareWidth = 0, squareHeight = 0;    int x = 0, y = 0;    Bitmap squareBitmap;    if (bmpHeight > bmpWidth) {// 高大于宽      squareWidth = squareHeight = bmpWidth;      x = 0;      y = (bmpHeight - bmpWidth) / 2;      // 截取正方形图片      squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth, squareHeight);    } else if (bmpHeight < bmpWidth) {// 宽大于高      squareWidth = squareHeight = bmpHeight;      x = (bmpWidth - bmpHeight) / 2;      y = 0;      squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth, squareHeight);    } else {      squareBitmap = bmp;    }     if (squareBitmap.getWidth() != diameter || squareBitmap.getHeight() != diameter) {      scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter, diameter, true);     } else {      scaledSrcBmp = squareBitmap;    }    Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(), scaledSrcBmp.getHeight(), Config.ARGB_8888);    Canvas canvas = new Canvas(output);     Paint paint = new Paint();    Rect rect = new Rect(0, 0, scaledSrcBmp.getWidth(), scaledSrcBmp.getHeight());     paint.setAntiAlias(true);    paint.setFilterBitmap(true);    paint.setDither(true);    canvas.drawARGB(0, 0, 0, 0);    canvas.drawCircle(scaledSrcBmp.getWidth() / 2, scaledSrcBmp.getHeight() / 2, scaledSrcBmp.getWidth() / 2, paint);    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));    canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);         bmp = null;    squareBitmap = null;    scaledSrcBmp = null;    return output;  }   /**   * 边缘画圆   */  private void drawCircleBorder(Canvas canvas, int radius, int color) {    Paint paint = new Paint();    /* 去锯齿 */    paint.setAntiAlias(true);    paint.setFilterBitmap(true);    paint.setDither(true);    paint.setColor(color);    /* 设置paint的　style　为STROKE：空心 */    paint.setStyle(Paint.Style.STROKE);    /* 设置paint的外框宽度 */    paint.setStrokeWidth(mBorderThickness);    canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);  } }</span><span style="font-size: 16pt;"></span>