Android 实现旋转木马的音乐效果

一、百度在线音乐旋转木马效果

就上面那个，当音乐在播放的时候，那个光碟轮子在转，就想旋转木马一般。感觉好好玩啊。
碰巧想起前阵子做音乐播放器，哎，那这个也可以做在手机的音乐播放器上，这样就代替了进度条了。
一想到，就兴奋，于是，首先画圆形，然后放置背景图片，然后使用动画旋转。当音乐播放时，同时
开始播放圆形图片的动画，当音乐暂停时，暂停旋转；当音乐停止播放时，就停止动画，图片回到原点。

二、效果

三、实现代码

（1）MainActivity  

<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>

（2）画圆的控件，这部分代码参考了网友的。

  <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);
  }
  
  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;
  }
  
  private void drawCircleBorder(Canvas canvas, int radius, int color) {
    Paint paint = new Paint();
    
    paint.setAntiAlias(true);
    paint.setFilterBitmap(true);
    paint.setDither(true);
    paint.setColor(color);
    
    paint.setStyle(Paint.Style.STROKE);
    
    paint.setStrokeWidth(mBorderThickness);
    canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);
  }
}</span><span style="font-size: 16pt;">
</span>

以上就是Android 实现旋转木马的音乐效果,有需要的朋友可以参考下。