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

 

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; } }