Android笔记 之 旋转木马的音乐效果

一、前言——

大家一定在百度音乐上在线听过歌，有没有注意到那个旋转唱片——

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，那这个也能够做在手机的音乐播放器上，这样就取代了进度条了。

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，同一时候

開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、源代码——

（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，这部分代码參考了网友的。

<span style="font-size:18px;">public class RoundImageView extends ImageView {
	private int mBorderThickness = 0;
	private Context mContext;
	private int defaultColor = 0xFFFFFFFF;
	// 假设仅仅有当中一个有值，则仅仅画一个圆形边框
	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();
		}
		// 保证又一次读取图片后不会由于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>