如何从android中的sd卡文件夹中卸载apk信息

Question

我想从sd卡/文件夹中删除带有标签名称和图标的apk文件信息，以便在列表视图中显示。

我正在尝试

     for (int i = 0; i < FilesInFolder.size(); i++)
     {

           PackageManager pm = this.getPackageManager();

           String dir = "mnt/sdcard/" + FilesInFolder.get(i);
           PackageInfo pi=pm.getPackageArchiveInfo(dir,0);
           System.err.println("files were " + pi);
           pi.applicationInfo.sourceDir = dir;
           pi.applicationInfo.publicSourceDir = dir;
           Drawable APKicon = pi.applicationInfo.loadIcon(pm);
           String AppName = (String)pi.applicationInfo.loadLabel(pm);

       }

FilesInFolder是ArrayList<String>，其中所有文件名都存储在sd卡文件夹中。我能够从sd卡文件夹中正确获取所有文件，但我的PackageInfo pi值为所有文件的空值

这是我的logcat

  10-29 00:55:14.832: W/PackageParser(17057): Skipping dir: mnt/sdcard/tudou.apk
  10-29 00:55:14.832: W/System.err(17057): files were null
  10-29 00:55:14.833: W/PackageParser(17057): Skipping dir:       mnt/sdcard/com.nexbits.video-1.apk
  10-29 00:55:14.833: W/System.err(17057): files were null
  10-29 00:55:14.834: W/PackageParser(17057): Skipping dir: mnt/sdcard/com.myapp.locksettings-2.apk
  10-29 00:55:14.834: W/System.err(17057): files were null

任何人都可以把我弄到我坚持的地方吗？