Android制作圆形ImageView

参考:圆形ImageView

效果图如下:

具体的解释请移步参考文章,这里只保留代码作为备份:

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package com.feng.meiya.widget.imageview;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
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;

public class CircleImageView extends ImageView {

//基本的三个构造函数
public CircleImageView(Context context) {
super(context);
}

public CircleImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}

public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

//自定义View实现过程中很重要的onDraw绘制图形的方法
@Override
protected void onDraw(Canvas canvas) {

Drawable drawable = getDrawable();

//空值判断,必要步骤,避免由于没有设置src导致的异常错误
if (drawable == null) {
return;
}

//必要步骤,避免由于初始化之前导致的异常错误
if (getWidth() == 0 || getHeight() == 0) {
return;
}

if (!(drawable instanceof BitmapDrawable)) {
return;
}
Bitmap b = ((BitmapDrawable) drawable).getBitmap();

if (null == b) {
return;
}

Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

int w = getWidth();

Bitmap roundBitmap = getCroppedBitmap(bitmap, w);
canvas.drawBitmap(roundBitmap, 0, 0, null);

}

/**
* 初始Bitmap对象的缩放裁剪过程
* @param bmp 初始Bitmap对象
* @param radius 圆形图片直径大小
* @return 返回一个圆形的缩放裁剪过后的Bitmap对象
*/
public static Bitmap getCroppedBitmap(Bitmap bmp, int radius) {
Bitmap sbmp;
//比较初始Bitmap宽高和给定的圆形直径,判断是否需要缩放裁剪Bitmap对象
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(),
Config.ARGB_8888);
Canvas canvas = new Canvas(output);

final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());

paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.parseColor("#BAB399"));
canvas.drawCircle(sbmp.getWidth() / 2 + 0.7f,
sbmp.getHeight() / 2 + 0.7f, sbmp.getWidth() / 2 + 0.1f, paint);
//核心部分,设置两张图片的相交模式,在这里就是上面绘制的Circle和下面绘制的Bitmap
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(sbmp, rect, rect, paint);

return output;
}

}