Android 使用Drawable实现圆角与圆形图案

第一步：创建类RoundCircleDrawable继承Drawable

/**
 * 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;
    }

}

2.实现方法

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);
    }
}

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