Android自定义View实现QQ音乐中圆形旋转碟子

QQ音乐中圆形旋转碟子

思路分析：
1、在onMeasure中测量整个View的宽和高后，设置宽高
2、获取我们res的图片资源后，在ondraw方法中进行绘制圆形图片
3、通过Handler发送Runnable来启动旋转线程（如果只想做圆形头像的话，这步可以去掉）
4、在布局中使用我们的View

效果图：

贴出我们的变量信息：

//view的宽和高 
int mHeight = 0; 
int mWidth = 0; 
//圆形图片 
Bitmap bitmap = null; 
//圆形图片的真实半径 
int radius = 0; 
//旋转动画的矩形 
Matrix matrix = new Matrix(); 
//旋转动画的角度 
int degrees = 0; 

步骤一：测量整个View的宽和高后，设置宽高

@Override 
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
 super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
 //测量整个View的宽和高 
 mWidth = measuredWidth(widthMeasureSpec); 
 mHeight= measuredHeight(heightMeasureSpec); 
 setMeasuredDimension(mWidth, mHeight); 
} 
private int measuredWidth(int widthMeasureSpec) { 
 int Mode = MeasureSpec.getMode(widthMeasureSpec); 
 int Size = MeasureSpec.getSize(widthMeasureSpec); 
 if (Mode == MeasureSpec.EXACTLY) { 
  mWidth = Size; 
 } else { 
  //由图片决定宽度 
  int value = getPaddingLeft() + getPaddingRight() + bitmap.getWidth(); 
  if (Mode == MeasureSpec.AT_MOST) { 
   //由图片和Padding决定宽度，但是不能超过View的宽 
   mWidth = Math.min(value, Size); 
  } 
 } 
 return mWidth; 
} 
private int measuredHeight(int heightMeasureSpec) { 
 int Mode = MeasureSpec.getMode(heightMeasureSpec); 
 int Size = MeasureSpec.getSize(heightMeasureSpec); 
 if (Mode == MeasureSpec.EXACTLY) { 
  mHeight = Size; 
 } else { 
  //由图片决定高度 
  int value = getPaddingTop() + getPaddingBottom() + bitmap.getHeight(); 
  if (Mode == MeasureSpec.AT_MOST) { 
   //由图片和Padding决定高度，但是不能超过View的高 
   mHeight = Math.min(value, Size); 
  } 
 } 
 return mHeight; 
} 

步骤二：获取我们res的图片资源后，在ondraw方法中进行绘制圆形图片

//获取res的图片资源 
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon); 
@Override 
protected void onDraw(canvas canvas) { 
 super.onDraw(canvas); 
 canvas.concat(matrix); 
 //真实的半径必须是View的宽高最小值 
 radius = Math.min(mWidth, mHeight); 
 //如果图片本身宽高太大，进行相应的缩放 
 bitmap = Bitmap.createScaledBitmap(bitmap, radius, radius, false); 
 //画圆形图片 
 canvas.drawBitmap(createCircleImage(bitmap, radius), 0, 0, null); 
 matrix.reset(); 
} 
private Bitmap createCircleImage(Bitmap source, int radius) { 
 Paint paint = new Paint(); 
 paint.setAntiAlias(true); 
 Bitmap target = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888); 
 //产生一个同样大小的画布 
 Canvas canvas = new Canvas(target); 
 //首先绘制圆形 
 canvas.drawCircle(radius / 2, radius / 2, radius / 2, paint); 
 //使用SRC_IN模式显示后画图的交集处 
 paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); 
 //绘制图片，从（0，0）画 
 canvas.drawBitmap(source, 0, 0, paint); 
 return target; 
} 

步骤三：通过Handler发送Runnable来启动旋转线程

//开始旋转 
mHandler.post(runnable); 
[java] view plain copy 在CODE上查看代码片派生到我的代码片
//-----------旋转动画----------- 
Handler mHandler = new Handler(); 
Runnable runnable = new Runnable() { 
 @Override 
 public void run() { 
  matrix.postRotate(degrees++, radius / 2, radius / 2); 
  //重绘 
  invalidate(); 
  mHandler.postDelayed(runnable, 50); 
 } 
}; 

步骤四：在布局中使用我们的View

<com.handsome.cycle.MyCycleView 
 Android:layout_width="wrap_content" 
 android:layout_height="wrap_content" /> 

下面是整个类的源码

public class MyCycleView extends View { 
 //view的宽和高 
 int mHeight = 0; 
 int mWidth = 0; 
 //圆形图片 
 Bitmap bitmap = null; 
 //圆形图片的真实半径 
 int radius = 0; 
 //旋转动画的矩形 
 Matrix matrix = new Matrix(); 
 //旋转动画的角度 
 int degrees = 0; 
 //-----------旋转动画----------- 
 Handler mHandler = new Handler(); 
 Runnable runnable = new Runnable() { 
  @Override 
  public void run() { 
   matrix.postRotate(degrees++, radius / 2, radius / 2); 
   //重绘 
   invalidate(); 
   mHandler.postDelayed(runnable, 50); 
  } 
 }; 
 public MyCycleView(Context context) { 
  super(context); 
  initView(); 
 } 
 public MyCycleView(Context context, AttributeSet attrs) { 
  super(context, attrs); 
  initView(); 
 } 
 public MyCycleView(Context context, AttributeSet attrs, int defStyleAttr) { 
  super(context, attrs, defStyleAttr); 
  initView(); 
 } 
 public void initView() { 
  //获取res的图片资源 
  bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon); 
  //开始旋转 
  mHandler.post(runnable); 
 } 
 @Override 
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
  super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
  //测量整个View的宽和高 
  mWidth = measuredWidth(widthMeasureSpec); 
  mHeight = measuredHeight(heightMeasureSpec); 
  setMeasuredDimension(mWidth, mHeight); 
 } 
 private int measuredWidth(int widthMeasureSpec) { 
  int Mode = MeasureSpec.getMode(widthMeasureSpec); 
  int Size = MeasureSpec.getSize(widthMeasureSpec); 
  if (Mode == MeasureSpec.EXACTLY) { 
   mWidth = Size; 
  } else { 
   //由图片决定宽度 
   int value = getPaddingLeft() + getPaddingRight() + bitmap.getWidth(); 
   if (Mode == MeasureSpec.AT_MOST) { 
    //由图片和Padding决定宽度，但是不能超过View的宽 
    mWidth = Math.min(value, Size); 
   } 
  } 
  return mWidth; 
 } 
 private int measuredHeight(int heightMeasureSpec) { 
  int Mode = MeasureSpec.getMode(heightMeasureSpec); 
  int Size = MeasureSpec.getSize(heightMeasureSpec); 
  if (Mode == MeasureSpec.EXACTLY) { 
   mHeight = Size; 
  } else { 
   //由图片决定高度 
   int value = getPaddingTop() + getPaddingBottom() + bitmap.getHeight(); 
   if (Mode == MeasureSpec.AT_MOST) { 
    //由图片和Padding决定高度，但是不能超过View的高 
    mHeight = Math.min(value, Size); 
   } 
  } 
  return mHeight; 
 } 
 @Override 
 protected void onDraw(Canvas canvas) { 
  super.onDraw(canvas); 
  canvas.concat(matrix); 
  //真实的半径必须是View的宽高最小值 
  radius = Math.min(mWidth, mHeight); 
  //如果图片本身宽高太大，进行相应的缩放 
  bitmap = Bitmap.createScaledBitmap(bitmap, radius, radius, false); 
  //画圆形图片 
  canvas.drawBitmap(createCircleImage(bitmap, radius), 0, 0, null); 
  matrix.reset(); 
 } 
 private Bitmap createCircleImage(Bitmap source, int radius) { 
  Paint paint = new Paint(); 
  paint.setAntiAlias(true); 
  Bitmap target = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888); 
  //产生一个同样大小的画布 
  Canvas canvas = new Canvas(target); 
  //首先绘制圆形 
  canvas.drawCircle(radius / 2, radius / 2, radius / 2, paint); 
  //使用SRC_IN模式显示后画图的交集处 
  paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN)); 
  //绘制图片，从（0，0）画 
  canvas.drawBitmap(source, 0, 0, paint); 
  return target; 
 } 
} 

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