android设置图片为圆角

大家好,这一节给大家分享的是Android中几种图像特效处理的小技巧,比如圆角,倒影,还有就是图片缩放,Drawable转化为Bitmap,Bitmap转化为Drawable等等.

废话少说了,直接讲解今天的实例,本例主要是先获取壁纸(getWallpaper()),然后对当前壁纸的一些特效处理.大家按步骤一步一步来:

第一步:新建一个Android工程命名为ImageDemo,工程结构如下:

第二步:新建一个.java文件,命名为ImageUtil.java,在里面定义一些图片处理方法,代码如下:

 package com.android.tutor;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.LinearGradient;
 import android.graphics.Matrix;
 import android.graphics.Paint;
 import android.graphics.PixelFormat;
 import android.graphics.PorterDuffXfermode;
 import android.graphics.Rect;
 import android.graphics.RectF;
 import android.graphics.Bitmap.Config;
 import android.graphics.PorterDuff.Mode;
 import android.graphics.Shader.TileMode;
 import android.graphics.drawable.Drawable;
 public class ImageUtil {

     //放大缩小图片
     public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){
         int width = bitmap.getWidth();
         int height = bitmap.getHeight();
         Matrix matrix = new Matrix();
         float scaleWidht = ((float)w / width);
         float scaleHeight = ((float)h / height);
         matrix.postScale(scaleWidht, scaleHeight);
         Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
         return newbmp;
     }
     //将Drawable转化为Bitmap
      public static Bitmap drawableToBitmap(Drawable drawable){
             int width = drawable.getIntrinsicWidth();
             int height = drawable.getIntrinsicHeight();
             Bitmap bitmap = Bitmap.createBitmap(width, height,
                     drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                             : Bitmap.Config.RGB_565);
             Canvas canvas = new Canvas(bitmap);
             drawable.setBounds(0,0,width,height);
             drawable.draw(canvas);
             return bitmap;

         }

      //获得圆角图片的方法
     public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){

         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);

         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;
     }
     //获得带倒影的图片方法
     public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){
         final int reflectionGap = 4;
         int width = bitmap.getWidth();
         int height = bitmap.getHeight();

         Matrix matrix = new Matrix();
         matrix.preScale(1, -1);

         Bitmap reflectionImage = Bitmap.createBitmap(bitmap,
                 0, height/2, width, height/2, matrix, false);

         Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height/2), Config.ARGB_8888);

         Canvas canvas = new Canvas(bitmapWithReflection);
         canvas.drawBitmap(bitmap, 0, 0, null);
         Paint deafalutPaint = new Paint();
         canvas.drawRect(0, height,width,height + reflectionGap,
                 deafalutPaint);

         canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

         Paint paint = new Paint();
         LinearGradient shader = new LinearGradient(0,
                 bitmap.getHeight(), 0, bitmapWithReflection.getHeight()
                 + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
         paint.setShader(shader);
         // Set the Transfer mode to be porter duff and destination in
         paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
         // Draw a rectangle using the paint with our linear gradient
         canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
                 + reflectionGap, paint);

         return bitmapWithReflection;
     }

 }

第三步:修改main.xml布局文件,主要放了两个ImageView控件,代码如下:

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     >
     <ImageView
         android:id="@+id/image01"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:padding="10px"
         />
     <ImageView
         android:id="@+id/image02"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:padding="10px"
     />
 </LinearLayout>

第四步:修改主核心程序,ImageDemo.java,代码如下:

 package com.android.tutor;
 import android.app.Activity;
 import android.graphics.Bitmap;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.widget.ImageView;
 public class Imagedemo extends Activity {
     private ImageView mImageView01,mImageView02;

     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         setupViews();
     }

     private void setupViews(){
         mImageView01 = (ImageView)findViewById(R.id.image01);
         mImageView02 = (ImageView)findViewById(R.id.image02);

         //获取壁纸返回值是Drawable
         Drawable drawable = getWallpaper();
         //将Drawable转化为Bitmap
         Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);
         //缩放图片
         Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);
         //获取圆角图片
         Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);
         //获取倒影图片
         Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);
         //这里可以让Bitmap再转化为Drawable
 //      Drawable roundDrawable = new BitmapDrawable(roundBitmap);
 //      Drawable reflectDrawable = new BitmapDrawable(reflectBitmap);
 //      mImageView01.setBackgroundDrawable(roundDrawable);
 //      mImageView02.setBackgroundDrawable(reflectDrawable);

         mImageView01.setImageBitmap(roundBitmap);
         mImageView02.setImageBitmap(reflectBitmap);
     }


 }

第五步:运行上述工程,查看效果如下:

 

OK大功告成了!!

 

本文参考文献:http://wiki.impjq.net/doku.php?id=code:android-code:image-convert&rev=1275640889&mddo=print

come from： http://blog.csdn.net/android_tutor/article/details/5981753