Android 实现图片的圆角

实现圆角的方法，此方法可以将一个位图改变为一个圆角位图：

/**
* 获取圆角位图的方法
* @param bitmap 需要转化成圆角的位图
* @param pixels 圆角的度数，数值越大，圆角越大
* @return 处理后的圆角位图
*/
public static Bitmap toRoundCorner(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 Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}

下面就测试一下这个方法，将一个Activity的背景图设置为圆角，即将Activity的LinerLayout的背景设置为圆角：

配置文件 main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

</LinearLayout>

Java代码：

import android.app.Activity;
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.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.widget.LinearLayout;

/**
* 将Activity的背景图设置为圆角图
*/
public class AndroidTestActivity extends Activity {

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

// Drawable drawable = getResources().getDrawable(R.drawable.bg);
// BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
// Bitmap bitmap = bitmapDrawable.getBitmap();
LinearLayout layout = (LinearLayout) findViewById(R.id.layout);
Drawable drawable = getResources().getDrawable(R.drawable.yexuan);
BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
Bitmap bitmap = bitmapDrawable.getBitmap();
BitmapDrawable bbb = new BitmapDrawable(toRoundCorner(bitmap, 30));
layout.setBackgroundDrawable(bbb);
// ImageView imageView = (ImageView) findViewById(R.id.imgShow);
// imageView.setImageBitmap(MyActivity.getRoundedCornerBitmap(bitmap));
// imageView.setImageBitmap(MyActivity.toRoundCorner(bitmap, 20));
}

/**
* 获取圆角位图的方法
* @param bitmap 需要转化成圆角的位图
* @param pixels 圆角的度数，数值越大，圆角越大
* @return 处理后的圆角位图
*/
public static Bitmap toRoundCorner(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 Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}

}

效果如下：


嘿嘿，成功了。。。

原文：http://www.javaask.com/mobile/android/2011/1013/9118.html