現在有的應用在使用者頭像上使用圓形的imageview,比如百度貼吧。實作上并不困難,需要寫一個類繼承自ImageView,重寫ondraw方法。
代碼如下:
public class CircleImage extends ImageView {
/**
* 3個構造函數
* @param context
*/
public CircleImage(Context context) {
super(context);
}
public CircleImage(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CircleImage(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
/**
* 重寫的ondraw方法
*/
@Override
protected void onDraw(Canvas canvas) {
Drawable drawable = getDrawable();
if (drawable == null) {
return;
}
if (getWidth() == 0 || getHeight() == 0) {
return;
}
Bitmap b = ((BitmapDrawable) drawable).getBitmap();
Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);
Bitmap roundBitmap = getCroppedBitmap(bitmap, getWidth());
canvas.drawBitmap(roundBitmap, 0, 0, null);
}
/**
* 對bitmap進行裁剪成圓形
* @param bmp
* @param radius
* @return
*/
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(),
Bitmap.Config.ARGB_8888);
final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
paint.setColor(Color.parseColor("#BAB399"));
Canvas c = new Canvas(output);
c.drawARGB(0, 0, 0, 0);
c.drawCircle(sbmp.getWidth() / 2 + 0.7f, sbmp.getHeight() / 2 + 0.7f,
sbmp.getWidth() / 2 + 0.1f, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
c.drawBitmap(sbmp, rect, rect, paint);
return output;
}
}
然後在imageview中可以通過xml的方式進行設定
<com.example.test.CircleImage
android:id="@+id/iv"
android:layout_width="70dp"
android:layout_height="70dp"
android:adjustViewBounds="true"
android:src="@drawable/img" />
com.example.test.CircleImage是包名+類名.
下面是實作的效果