Android开发之--读取文件夹下图片生成略缩图并点击显示大图

     这是一个简单的Demo，目的是：读取文件夹下图片生成略缩图并点击显示大图。    <p></p> 先新建一个工程，创建一个ThumbnailsWindows的类，继承LinearLayout。代码如下：    <pre class="brush:java; toolbar: true; auto-links: false;"> package org.winplus.thum.view;  import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.InputStream; import java.util.ArrayList; import java.util.Collections; import java.util.Iterator; import java.util.Map; import java.util.TreeMap;  import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.widget.ImageButton; import android.widget.ImageView; import android.widget.LinearLayout; import cn.embel.thum.R;  public class ThumbnailsWindows extends LinearLayout {   private static final String TAG = "ThumbnailsWindows";  private Context mContext;  private static ArrayList<String> paths = new ArrayList<String>();    private ImageView imageView;    public ThumbnailsWindows(Context context) {   super(context);   mContext = context;   setupViews();  }   public ThumbnailsWindows(Context context, AttributeSet attrs) {   super(context, attrs);   mContext = context;   setupViews();  }   public void setupViews() {      /**    * 显示大图时需要使用，当然可以直接在此类中定义！这样还好控制一些~到时候再改吧，赶这过年呢    */   final LayoutInflater mLayoutInflater = LayoutInflater.from(getContext());   View v = mLayoutInflater.inflate(R.layout.original_photo, null);   imageView =  (ImageView) v.findViewById(R.id.original);      Map<String,Bitmap> maps = new TreeMap<String, Bitmap>();   try {    maps = buildThum();   } catch (FileNotFoundException e) {    e.printStackTrace();   }      Iterator<String> it = maps.keySet().iterator();   int i = 0;   while (it.hasNext()) {    String path = (String) it.next();      Bitmap bm = maps.get(path);          ImageButton image = new ImageButton(mContext);     image.setImageBitmap(bm);    image.setId(i++);    addView(image);    image.setOnTouchListener(listener);   }      addView(v);  }    /**   * 定义按钮控件的Touch事件   */  OnTouchListener listener = new OnTouchListener() {   @Override   public boolean onTouch(View v, MotionEvent event) {    /**     * 控件按下的时候显示当前略缩图的大图     */    if(event.getAction() == MotionEvent.ACTION_DOWN){     String path = paths.get(v.getId());     InputStream inputStream = null;     try {      inputStream = new FileInputStream(path);     } catch (FileNotFoundException e) {      e.printStackTrace();     }     Bitmap bitmap = BitmapFactory.decodeStream(inputStream);     imageView.setImageBitmap(bitmap);    }    return false;   }  };    /**   * 获取图片地址列表   * @param file   * @return   */  private static ArrayList<String> imagePath(File file) {   ArrayList<String> list = new ArrayList<String>();    File[] files = file.listFiles();   for (File f : files) {    list.add(f.getAbsolutePath());   }   Collections.sort(list);   return list;  }   /**   * 读取sdcard文件夹中的图片，并生成略缩图   * @return   * @throws FileNotFoundException   */  private Map<String,Bitmap> buildThum() throws FileNotFoundException {   File baseFile = new File("/mnt/sdcard/tflash/image/");   // 使用TreeMap，排序问题就不需要纠结了   Map<String,Bitmap> maps = new TreeMap<String, Bitmap>();   if (baseFile != null && baseFile.exists()) {    paths = imagePath(baseFile);     if (!paths.isEmpty()) {     for (int i = 0; i < paths.size(); i++) {       BitmapFactory.Options options = new BitmapFactory.Options();       options.inJustDecodeBounds = true; // 设置了此属性一定要记得将值设置为false       Bitmap bitmap =BitmapFactory.decodeFile(paths.get(i),options);       options.inJustDecodeBounds = false;       int be = options.outHeight/40;       if (be <= 0) {        be = 10;       }       options.inSampleSize = be;       bitmap = BitmapFactory.decodeFile(paths.get(i),options);       maps.put(paths.get(i), bitmap);     }    }   }    return maps;  } }  </pre>    <span style="font-size:16px;"><span style="font-size:16px;">修改mail.xml文件<pre class="brush:xml; toolbar: true; auto-links: false;"><span style="font-size: 16px; "><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:orientation="vertical" >      <org.winplus.thum.view.ThumbnailsWindows         android:layout_width="fill_parent"         android:layout_height="fill_parent" />      </LinearLayout></span></pre><img title="0_13267077305hgt.gif" border="0" alt="0_13267077305hgt.gif" src="https://simg.open-open.com/show/0aace7e9596f2f7e548188941879dcf6.gif" width="700" height="525" /></span></span>    <p></p>    <p><span style="font-size:16px;">本Demo还有Bug，稍后在修改吧，看能否经过修改，改成像Ihone图片浏览器一样的效果. <br /> </span></p>    <p><span style="font-size:16px;"><a href="/misc/goto?guid=4959500912853414016">源码下载==》</a></span></p>    <p><span style="font-size:16px;">原创文章，转载请注明出处：<a href="/misc/goto?guid=4959500912931661596">http://blog.csdn.net/tangcheng_ok</a></span></p>