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前段时间对Android的paint和canvas做了深入的了解,针对于开发过程中遇到的头像几乎都是圆形的问题,抽空写了个demo,,废话不多说,直接上代码。
首先自定义一个view,继承imageview。关于PorterDuff及Xfermode详解可点击链接,代码中就不做详细解释
<span style="font-size:18px;color:#009900;"><span style="color:#009900;">package com.example.text;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Xfermode;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;
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; //取两层绘制交集。显示上层。
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);
}
}
}</span></span>
然后再自定义一个类,继承上面自定义的MaskedImage。关于paint和canvas的详解点击打开链接
<span style="font-size:18px;color:#009900;"><span style="color:#009900;">package com.example.text;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
public class CircularImage extends MaskedImage{
public CircularImage(Context paramContext) {
super(paramContext);
// TODO Auto-generated constructor stub
}
public CircularImage(Context paramContext, AttributeSet paramAttributeSet) {
super(paramContext, paramAttributeSet);
}
public CircularImage(Context paramContext, AttributeSet paramAttributeSet, int paramInt) {
super(paramContext, paramAttributeSet, paramInt);
}
@Override
public Bitmap createMask() {
// TODO Auto-generated method stub
int i = getWidth();
int j = getHeight();
Bitmap.Config localConfig = Bitmap.Config.ARGB_8888; //Bitmap.Config是图片的质量参数,工四种,常用ARGB_8888(ALPHA_8,ARGB_4444,ARGB_8888,RGB_565)
Bitmap localBitmap = Bitmap.createBitmap(i, j, localConfig); //剪裁图片
Canvas localCanvas = new Canvas(localBitmap); //画布
Paint localPaint = new Paint(1); //画笔
localPaint.setColor(-16777216);
float f1 = getWidth();
float f2 = getHeight();
RectF localRectF = new RectF(0.0F, 0.0F, f1, f2); //画矩形
localCanvas.drawOval(localRectF, localPaint);
return localBitmap; }
}</span></span>
到这自定义的view就算完成了,在xml布局中引用就可以。
<span style="font-size:18px;color:#009900;"><span style="color:#009900;"><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" >
<com.example.text.CircularImage
android:id="@+id/cover_user_photo"
android:layout_width="74.0dip"
android:layout_height="74.0dip"
/>
</RelativeLayout> </span></span>
MainActivity的代码。
<span style="font-size:18px;color:#009900;"><span style="color:#009900;">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);
}
}</span></span>
效果图如下: