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Android ImageView 图片圆角显示(转载)

转载自:http://www.w2bc.com/Article/3623

android中的ImageView只能显示矩形的图片,这样一来不能满足我们其他的需求,比如要显示圆形的图片,这个时候,我们就需要自定义ImageView了,其原理就是首先获取到图片的Bitmap,然后进行裁剪圆形的bitmap,然后在onDraw()进行绘制圆形图片输出。

自定义的圆形的ImageView类的实现代码如下:

package com.rainwii.entity;//包名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.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.widget.ImageView;/** * * 自定义的圆形ImageView,可以直接当组件在布局中使用。 *  * @author caizhiming * */public class XCRoundImageView extends ImageView {    private Paint paint;    public XCRoundImageView(Context context) {        this(context, null);    }    public XCRoundImageView(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public XCRoundImageView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        paint = new Paint();    }    /**     * * 绘制圆形图片     *      * @author caizhiming     */    @Override    protected void onDraw(Canvas canvas) {        Drawable drawable = getDrawable();        if (null != drawable) {            Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();            Bitmap b = getCircleBitmap(bitmap, 14);            final Rect rectSrc = http://www.mamicode.com/new Rect(0, 0, b.getWidth(), b.getHeight());            final Rect rectDest = new Rect(0, 0, getWidth(), getHeight());            paint.reset();            canvas.drawBitmap(b, rectSrc, rectDest, paint);        } else {            super.onDraw(canvas);        }    }    /**     * * 获取圆形图片方法     *      * @param bitmap     * @param pixels     * @return Bitmap     * @author caizhiming     */    private Bitmap getCircleBitmap(Bitmap bitmap, int pixels) {        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),                bitmap.getHeight(), Config.ARGB_8888);        Canvas canvas = new Canvas(output);        final int color = 0xff424242;        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());        paint.setAntiAlias(true);        canvas.drawARGB(0, 0, 0, 0);        paint.setColor(color);        int x = bitmap.getWidth();        canvas.drawCircle(x / 2, x / 2, x / 2, paint);        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));        canvas.drawBitmap(bitmap, rect, rect, paint);        return output;    }}

完成这个自定义类后,就可以使用这个类了,就是把这个当组件在布局中使用即可,比如:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools
="http://schemas.android.com/tools"
android:layout_width
="match_parent"
android:layout_height
="match_parent" > <com.rainwii.entity.XCRoundImageView android:id="@+id/roundImageView"
    android:layout_centerInParent
="true"
    android:layout_width="200dp"
    android:layout_height
="200dp"
    android:src
="@drawable/roundimageview" /></RelativeLayout>

补充学员资料:http://my.oschina.net/sammy1990/blog/316400

                    http://blog.csdn.net/lmj623565791/article/details/24555655

Android ImageView 图片圆角显示(转载)