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);
        }
    }
}

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);
        }
    }
}

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：

 

 

<SPAN style="FONT-SIZE: 14px">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;
    }
}</SPAN>

<span style="font-size: 14px;">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;
    }
}</span>

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);
    }
}

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);
    }
}

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>

               <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>
<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>