实现Android图片圆角

这里介绍一个主要的方法，也是从网上找的，在此整理出来。。。以备不时之需

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;      }

当我们需要圆角的时候，调用这个方法，第一个参数是传入需要转化成圆角的图片，第二个参数是圆角的度数，数值越大，圆角越大

下面兴趣个例子，我有一个LinearLayout，我想把它的背景图片设置成圆角

布局文件main.xml

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

package com.test.demo;import android.app.Activity;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.RectF;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.Drawable;import android.os.Bundle;import android.widget.ImageView;import android.widget.LinearLayout;public class MyActivity 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.bg);        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));    }    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;      }}

当然对ImageView设置图片也可以，不仅是background属性

上面那个类中注释的代码就是