【Android 界面效果44】Android之圆头像实例

在很多应用中，我们看到，个人主页里面的头像一般都是圆的，设计成圆的会使整个界 面布 局变的优雅漂亮。那么，怎么使头像变圆呢？有的人说可以在上面加一个中间为透明圆形的png图，用它来遮盖住头像不就行了嘛，但是png四周始终始终是不 透明的，怎么做也达不到如下的效果图的。

下面我们讲讲怎么做成的吧。

首先创建一个继承ImageView的抽象类MaskedImage。让他重写onDraw方法。代码如下

    public abstract class MaskedImage extends ImageView {
        private static final Xfermode MASK_XFERMODE;
        private Bitmap mask;
        private Paint paint;  

        static {
            PorterDuff.Mode localMode = PorterDuff.Mode.DST_IN;
            MASK_XFERMODE = new PorterDuffXfermode(localMode);
        }  

        public MaskedImage(Context paramContext) {
            super(paramContext);
        }  

        public MaskedImage(Context paramContext, AttributeSet paramAttributeSet) {
            super(paramContext, paramAttributeSet);
        }  

        public MaskedImage(Context paramContext, AttributeSet paramAttributeSet, int paramInt) {
            super(paramContext, paramAttributeSet, paramInt);
        }  

        public abstract Bitmap createMask();  

        protected void onDraw(Canvas paramCanvas) {
            Drawable localDrawable = getDrawable();
            if (localDrawable == null)
                return;
            try {
                if (this.paint == null) {
                    Paint localPaint1 = new Paint();
                    this.paint = localPaint1;
                    this.paint.setFilterBitmap(false);
                    Paint localPaint2 = this.paint;
                    Xfermode localXfermode1 = MASK_XFERMODE;
                    @SuppressWarnings("unused")
                    Xfermode localXfermode2 = localPaint2.setXfermode(localXfermode1);
                }
                float f1 = getWidth();
                float f2 = getHeight();
                int i = paramCanvas.saveLayer(0.0F, 0.0F, f1, f2, null, 31);
                int j = getWidth();
                int k = getHeight();
                localDrawable.setBounds(0, 0, j, k);
                localDrawable.draw(paramCanvas);
                if ((this.mask == null) || (this.mask.isRecycled())) {
                    Bitmap localBitmap1 = createMask();
                    this.mask = localBitmap1;
                }
                Bitmap localBitmap2 = this.mask;
                Paint localPaint3 = this.paint;
                paramCanvas.drawBitmap(localBitmap2, 0.0F, 0.0F, localPaint3);
                paramCanvas.restoreToCount(i);
                return;
            } catch (Exception localException) {
                StringBuilder localStringBuilder = new StringBuilder()
                        .append("Attempting to draw with recycled bitmap. View ID = ");
                System.out.println("localStringBuilder=="+localStringBuilder);
            }
        }
    }

然后新建一个类CircularImage继承MaskedImage。代码如下：

public class CircularImage extends MaskedImage {
    public CircularImage(Context paramContext) {
        super(paramContext);
    }  

    public CircularImage(Context paramContext, AttributeSet paramAttributeSet) {
        super(paramContext, paramAttributeSet);
    }  

    public CircularImage(Context paramContext, AttributeSet paramAttributeSet, int paramInt) {
        super(paramContext, paramAttributeSet, paramInt);
    }  

    public Bitmap createMask() {
        int i = getWidth();
        int j = getHeight();
        Bitmap.Config localConfig = Bitmap.Config.ARGB_8888;
        Bitmap localBitmap = Bitmap.createBitmap(i, j, localConfig);
        Canvas localCanvas = new Canvas(localBitmap);
        Paint localPaint = new Paint(1);
        localPaint.setColor(-16777216);
        float f1 = getWidth();
        float f2 = getHeight();
        RectF localRectF = new RectF(0.0F, 0.0F, f1, f2);
        localCanvas.drawOval(localRectF, localPaint);
        return localBitmap;
    }
}

新建一个MainActivity，代码如下：

    public class MainActivity extends Activity {  

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);  

            CircularImage cover_user_photo = (CircularImage) findViewById(R.id.cover_user_photo);
            cover_user_photo.setImageResource(R.drawable.face);
        }
    }

其XML布局文件为：

<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"
        android:gravity="center" >  

        <ImageView
            android:layout_width="82.0dip"
            android:layout_height="82.0dip"
            android:layout_centerInParent="true"
            android:contentDescription="@null"
            android:src="@drawable/me_head_bg" />  

        <com.doublefi123.diary.widget.CircularImage
            android:id="@+id/cover_user_photo"
            android:layout_width="74.0dip"
            android:layout_height="74.0dip"
            android:layout_centerInParent="true" />  

    </RelativeLayout>

源码在此：http://download.csdn.net/detail/dongdong230/8428989 (免费奉献源码)