android为图片生成缩略图

android api里自带了一个Bitmap类，用于处理图片。不是很难，直接上代码

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package com.forwork.thumbnail; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.os.Bundle; 
import android.util.Log; 
public class Thumbnail extends Activity { 
/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.main); 
try { 
saveMyBitmap("ooo"); 
} catch (IOException e) { 
// TODO Auto-generated catch block 
e.printStackTrace(); 
} 
} 
public void saveMyBitmap(String bitName) throws IOException { 
File originalFile = new File("sdcard/pic/ll.jpg"); 
Bitmap bmp = decodeFile(originalFile); 
File f = new File("/sdcard/" + bitName + ".jpg"); 
f.createNewFile(); 
FileOutputStream fOut = null; 
try { 
fOut = new FileOutputStream(f); 
} catch (FileNotFoundException e) { 
e.printStackTrace(); 
} 
//BitmapFactory.Options options=new BitmapFactory.Options(); 
        //options.inSampleSize = 10; 
//options.inTempStorage = new byte[16*1024]; 
//Bitmap bmp = BitmapFactory.decodeFile("/sdcard/pic/sd.jpg"); 
//Bitmap bmp = BitmapFactory.decodeFile("/sdcard/pic/ll.jpg", options); 
//bmp = Bitmap.createScaledBitmap(bmp, 800, 480, true); 
bmp.compress(Bitmap.CompressFormat.JPEG, 30, fOut); 
try { 
fOut.flush(); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
try { 
fOut.close(); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
} 
//decodes image and scales it to reduce memory consumption 
private Bitmap decodeFile(File f){ 
    try { 
        //Decode image size 
        BitmapFactory.Options o = new BitmapFactory.Options(); 
        o.inJustDecodeBounds = true; 
        BitmapFactory.decodeStream(new FileInputStream(f),null,o); 
        //The new size we want to scale to 
        final int REQUIRED_HEIGHT=800; 
        final int REQUIRED_WIDTH=480; 
        //Find the correct scale value. It should be the power of 2. 
        int width_tmp=o.outWidth, height_tmp=o.outHeight; 
         
        System.out.println(width_tmp+"  "+height_tmp); 
        Log.w("===", (width_tmp+"  "+height_tmp)); 
         
        int scale=1; 
        while(true){ 
            if(width_tmp/2<REQUIRED_WIDTH && height_tmp/2<REQUIRED_HEIGHT) 
                break; 
            width_tmp/=2; 
            height_tmp/=2; 
            scale++; 
             
            Log.w("===", scale+"''"+width_tmp+"  "+height_tmp); 
        } 
        //Decode with inSampleSize 
        BitmapFactory.Options o2 = new BitmapFactory.Options(); 
        o2.inSampleSize=scale; 
        return BitmapFactory.decodeStream(new FileInputStream(f), null, o2); 
    } catch (FileNotFoundException e) {} 
    return null; 
} 
}