如何从SDCARD加载listview中的apk文件

Question

这是我下面的代码，它显示了listview中的所有系统应用程序图标，但我想显示位于sdcard内的所有file.apk图标如何更改此代码，因此只更改了在Sdcard内的apk。 / p>

 import java.io.File;
  import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import android.net.Uri;

 public class MainActivity extends Activity implements OnItemClickListener {

   /* whether or not to include system apps */
   private static final boolean INCLUDE_SYSTEM_APPS = false;

   private ListView mAppsList;
   private AppListAdapter mAdapter;
   private List<App> mApps;

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      mAppsList = (ListView) findViewById(R.id.appslist);
      mAppsList.setOnItemClickListener(this);

      mApps = loadInstalledApps(INCLUDE_SYSTEM_APPS);

      mAdapter = new AppListAdapter(getApplicationContext());
      mAdapter.setListItems(mApps);
      mAppsList.setAdapter(mAdapter);

      new LoadIconsTask().execute(mApps.toArray(new App[]{}));
   }

   @Override
   public void onItemClick(AdapterView<?> parent, View view, int position, long 
       id) {

      final App app = (App) parent.getItemAtPosition(position);

      AlertDialog.Builder builder = new AlertDialog.Builder(this);

      String msg = app.getTitle() + "\n\n" + 
         "Version " + app.getVersionName() + " (" +
         app.getVersionCode() + ")" +
         (app.getDescription() != null ? ("\n\n" + app.getDescription()) : "");

      builder.setMessage(msg)
      .setCancelable(true)
      .setTitle(app.getTitle())
      .setIcon(mAdapter.getIcons().get(app.getPackageName()))
      .setPositiveButton("Launch", new DialogInterface.OnClickListener() {
         public void onClick(DialogInterface dialog, int id) {
            // start the app by invoking its launch intent
            Intent i = 
   getPackageManager().getLaunchIntentForPackage(app.getPackageName());
            try {
               if (i != null) {
                  startActivity(i);
               } else {
                  i = new Intent(app.getPackageName());
                  startActivity(i);
               }
            } catch (ActivityNotFoundException err) {
               Toast.makeText(MainActivity.this, "Error launching app", 
  Toast.LENGTH_SHORT).show();
            }
         }
      })
      .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
         public void onClick(DialogInterface dialog, int id) {
            dialog.cancel();
         }
      });
      AlertDialog dialog = builder.create();
      dialog.show();
   }

   /**
    * Uses the package manager to query for all currently installed apps which are 
 put into beans and returned
    * in form of a list.
    * 
    * @param includeSysApps whether or not to include system applications
    * @return a list containing an {@code App} bean for each installed application 
    */
   private List<App> loadInstalledApps(boolean includeSysApps) {
      List<App> apps = new ArrayList<App>();

      // the package manager contains the information about all installed apps
      PackageManager packageManager = getPackageManager();

      List<PackageInfo> packs = packageManager.getInstalledPackages(0); 
     //PackageManager.GET_META_DATA 





      for(int i=0; i < packs.size(); i++) {
         PackageInfo p = packs.get(i);

     ApplicationInfo a = p.applicationInfo;


     if ((!includeSysApps) && ((a.flags & ApplicationInfo.FLAG_SYSTEM) == 1)) {


         App app = new App();
         app.setTitle(p.applicationInfo.loadLabel(packageManager).toString());
         app.setPackageName(p.packageName);
         app.setVersionName(p.versionName);
         app.setVersionCode(p.versionCode);
         CharSequence description = 
    p.applicationInfo.loadDescription(packageManager);
         app.setDescription(description != null ? description.toString() : "");
         apps.add(app);
      }
      }
      return apps;
   }

   /**
    * An asynchronous task to load the icons of the installed applications.
    */
   private class LoadIconsTask extends AsyncTask<App, Void, Void> {
      @Override
      protected Void doInBackground(App... apps) {

         Map<String, Drawable> icons = new HashMap<String, Drawable>();
         PackageManager manager = getApplicationContext().getPackageManager();

         for (App app : apps) {
            String pkgName = app.getPackageName();
            Drawable ico = null;
            try {
               Intent i = manager.getLaunchIntentForPackage(pkgName);
               if (i != null) {
                  ico = manager.getActivityIcon(i);
               }
            } catch (NameNotFoundException e) {
               Log.e("ERROR", "Unable to find icon for package '" + pkgName + "': 
     " + e.getMessage());
            }
            icons.put(app.getPackageName(), ico);
         }
         mAdapter.setIcons(icons);

         return null;
      }

      @Override
      protected void onPostExecute(Void result) {
         mAdapter.notifyDataSetChanged();
      }
  }

}