Android自定义控件实现UC浏览器语音搜索效果

public class CustomCircleView extends View{
  private Paint mPaint;
  private int strokeWidth = 0;   //圆环的宽度
  private Bitmap bitmap = null;  // 图片位图
  private int nBitmapWidth = 0;  // 图片的宽度
  private int nBitmapHeight = 0; // 图片的高度
  private int width;     //view的宽度
  private int height ;    //view的高度
  private int bigCircleColor =0;    //view的高度
  private int floatCircleColor =0;    //view的高度

  public CustomCircleView(Context context) {
    this(context, null);
  }

  public CustomCircleView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }

  public CustomCircleView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomCircleView, defStyleAttr, 0);
    int n = a.getIndexCount();

    for (int i = 0; i < n; i++)
    {
      int attr = a.getIndex(i);
      switch (attr)
      {
        case R.styleable.CustomCircleView_icon:
          bitmap = BitmapFactory.decodeResource(getResources(), a.getResourceId(attr, 0));
          break;
        case R.styleable.CustomCircleView_bigCircleColor:
          bigCircleColor = a.getColor(attr, Color.GRAY);
          break;
        case R.styleable.CustomCircleView_floatCircleColor:
          floatCircleColor = a.getColor(attr,Color.GREEN);
          break;
      }
    }
    a.recycle();

    mPaint = new Paint();
    //如果布局中没有设置bigCircleColor和floatCircleColor的时候给他一个默认值
    if (bigCircleColor==0){
      bigCircleColor=Color.parseColor("#FFEEF0F1");
    }
    if (floatCircleColor==0){
      floatCircleColor=Color.parseColor("#25c1f5");
    }
    // 获取图片高度和宽度
    nBitmapWidth = bitmap.getWidth();
    nBitmapHeight = bitmap.getHeight();
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    int widthSize = MeasureSpec.getSize(widthMeasureSpec);
    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);

    //获取view的高度和宽度 这个view必须给精确值！！！！！！！！
    if (widthMode == MeasureSpec.EXACTLY) {
      width = widthSize;
    }
    if (heightMode == MeasureSpec.EXACTLY)
    {
      height = heightSize;
    }
    setMeasuredDimension(width, height);
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    mPaint.setAntiAlias(true); // 消除锯齿
    //绘制最外层灰色大圆
    mPaint.setColor(bigCircleColor);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(height/2-nBitmapHeight/2);
    //计算圆的半径稍微麻烦点，但是在图上画一下应该能明白 (height/2-nBitmapHeight/2)/2+nBitmapHeight/2
    canvas.drawCircle(width/2, height/2, (height/2-nBitmapHeight/2)/2+nBitmapHeight/2, mPaint);

    //绘制浮动的圆
    mPaint.setColor(floatCircleColor);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(strokeWidth);
    canvas.drawCircle(width/2, height/2, strokeWidth/2+nBitmapHeight/2, mPaint);

    //绘制中间图标
    canvas.drawBitmap(bitmap, width/2-nBitmapWidth/2, height/2-nBitmapHeight/2, mPaint);


  }
  //根据传入的宽度重新绘制
  public void setStrokeWidth(int with){
    this.strokeWidth=with;
    invalidate();
  }
}

<resources>
  <declare-styleable name="CustomCircleView">
    <attr name="bigCircleColor" format="color" />
    <attr name="floatCircleColor" format="color" />
    <attr name="icon" format="reference" />
  </declare-styleable>
</resources>

<com.example.administrator.mycustomcircleview.CustomCircleView
  android:id="@+id/customView"
  android:layout_width="200dp"
  android:layout_height="200dp"
  android:layout_gravity="center"
  app:icon="@mipmap/voice_icon"
  app:floatCircleColor="@color/colorAccent"
  app:bigCircleColor="@color/colorPrimaryDark"
  />

customView = ((CustomCircleView) findViewById(R.id.customView));
  button = ((Button) findViewById(R.id.button));
  button.setOnClickListener(this);
}

@Override
public void onClick(View v) {
  Random random=new Random();
  customView.setStrokeWidth(random.nextInt(100));
}