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>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> </span>

（2）画圆的控件，这部分代码参考了网友的。

<span>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> </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。