Android开发使用Drawable绘制圆角与圆形图案功能示例

/**
 * 圆角矩形
 * @Project  App_View
 * @Package  com.android.view.drawable
 * @author   chenlin
 * @version  1.0
 * @Date    2016年4月21日
 * @Note    TODO
 */
public class RoundCircleDrawable extends Drawable{
  private Paint mPaint;//画笔
  private int mWidth;//图片宽与长度的最小值
  private int mRadius;//半径
  private int mRound;//圆角
  private RectF mRectF;//矩形
  private Bitmap mBitmap;//图片
  private Type mType = Type.TYPE_ROUND;//默认是矩形
  //设置类型
  enum Type{
    TYPE_ROUND, TYPE_CICLE;
  }
  public RoundCircleDrawable(Bitmap bitmap){
    this.mBitmap = bitmap;
    //初始化画笔
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    BitmapShader shader = new BitmapShader(mBitmap, TileMode.CLAMP, TileMode.CLAMP);
    mPaint.setShader(shader);
    mWidth = Math.min(mBitmap.getWidth(), mBitmap.getHeight());
    mRadius = mWidth / 2;
  }
  /**
   * 向外提供设置图片类型的方法
   * @param type
   */
  public void setType(Type type){
    this.mType = type;
  }
  /**
   * 暴露给外面设置圆角的大小
   * 
   * @param round
   */
  public void setRound(int round) {
    this.mRound = round;
  }
  @Override
  public void setBounds(int left, int top, int right, int bottom) {
    super.setBounds(left, top, right, bottom);
    mRectF = new RectF(left, top, right, bottom);
  }
  @Override
  public void draw(Canvas canvas) {
    if (mType == Type.TYPE_ROUND) {
      canvas.drawRoundRect(mRectF, mRound, mRound, mPaint);
    }else {
      canvas.drawCircle(mWidth / 2, mWidth / 2, mRadius, mPaint);
    }
  }
  @Override
  public int getIntrinsicWidth() {
    if (mType == Type.TYPE_CICLE) {
      return mWidth;
    }else {
      return mBitmap.getWidth();
    }
  }
  @Override
  public int getIntrinsicHeight() {
    if (mType == Type.TYPE_CICLE) {
      return mWidth;
    }else {
      return mBitmap.getHeight();
    }
  }
  @Override
  public void setAlpha(int alpha) {
    mPaint.setAlpha(alpha);
  }
  @Override
  public void setColorFilter(ColorFilter cf) {
    mPaint.setColorFilter(cf);
  }
  @Override
  public int getOpacity() {
    return PixelFormat.TRANSLUCENT;
  }
}

public class RoundActivity extends Activity {
  private ImageView mImageView;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_round_drawable);
    mImageView = (ImageView) findViewById(R.id.iv_round);
    Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.aa);
    //RoundImageDrawable drawable = new RoundImageDrawable(bitmap);
    //drawable.setRound(30);
    RoundCircleDrawable drawable = new RoundCircleDrawable(bitmap);
    drawable.setRound(50);
    mImageView.setImageDrawable(drawable);
  }
}