android 自定義圓形imageview控件

首先，定義定義圓形Imageview類：

import android.content.Context;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class RoundImageView extends ImageView {

public RoundImageView(Context context) {
    super(context);
    // TODO Auto-generated constructor stub
}

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

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

@Override
protected void onDraw(Canvas canvas) {

    Drawable drawable = getDrawable();

    if (drawable == null) {
        return;
    }

    if (getWidth() == 0 || getHeight() == 0) {
        return; 
    }
    
    Bitmap b =  ((BitmapDrawable)drawable).getBitmap();
    
    if(null == b)
    {
    	return;
    }
    
    Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

    int w = getWidth(), h = getHeight();


    Bitmap roundBitmap =  getCroppedBitmap(bitmap, w);
    canvas.drawBitmap(roundBitmap, 0,0, null);

}

public static Bitmap getCroppedBitmap(Bitmap bmp, int radius) {
    Bitmap sbmp;
    if(bmp.getWidth() != radius || bmp.getHeight() != radius)
        sbmp = Bitmap.createScaledBitmap(bmp, radius, radius, false);
    else
        sbmp = bmp;
    Bitmap output = Bitmap.createBitmap(sbmp.getWidth(),
            sbmp.getHeight(), Config.ARGB_8888);
    Canvas canvas = new Canvas(output);

    final int color = 0xffa19774;
    final Paint paint = new Paint();
    final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());

    paint.setAntiAlias(true);
    paint.setFilterBitmap(true);
    paint.setDither(true);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(Color.parseColor("#BAB399"));
    canvas.drawCircle(sbmp.getWidth() / 2+0.7f, sbmp.getHeight() / 2+0.7f,
            sbmp.getWidth() / 2+0.1f, paint);
    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
    canvas.drawBitmap(sbmp, rect, rect, paint);


            return output;
}

}

然後在別的布局文件中使用該控件即可，如：