圆形图片

imageview一般情况下为矩形，如果需要现实为圆角或者圆形还需要进行一番处理，这里自定义了一个imageview，可以修改角度来显示圆角图片

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
*  类名 CircleImageView
*  @author 王洪贺<br/>
*    圆形图像类
*    创建日期 2014年7月14日
*/
public class CircleImageView extends ImageView {

    /**默认显示的图像*/
    private int defaultImageRes = R.drawable.no_image;
    /**网络图像地址*/
    private String url;
    /**上下文*/
    private Context mContext;

    public CircleImageView(Context context) {
        super(context);
        init(context);
    }

    public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context);
    }

    public CircleImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }

    public void init(Context context) {
        this.mContext = context;
    }

    public void setDefault(int resId) {
        defaultImageRes = resId;
    }

    public void setUrl(String imageUrl) {
        url = imageUrl;
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        if (bm != null) {
            bm = toRoundBitmap(bm);
            // bitmap = bm;
        }
        super.setImageBitmap(bm);
    }

    @Override
    public void setImageResource(int resId) {
        super.setImageResource(resId);

    }

    /**
     * 转换图片成圆形
     * 
     * @param bitmap
     *            传入Bitmap对象
     * @return
     */
    public Bitmap toRoundBitmap(Bitmap bitmap) {

        Bitmap output = Bitmap
                .createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);
        final float roundPx = 90;

        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return output;
    }

}