Android的PackageManager类用于检索目前安装在设备上的应用软件包的信息。你可以通过调用getpackagemanager()得到PackageManager类的一个实例。对查询和操作安装包和相关的权限提供了方法，在下面这个Android的例子中，我们得到了在Android安装的应用程序列表。

PackageManager packageManager = getPackageManager();List
    
      list = packageManager.getInstalledApplications(PackageManager.GET_META_DATA)复制代码
    

packageManager.getInstalledApplications()返回一个列表都是安装在设备上的应用程序包。如果我们把 flag GET_UNINSTALLED_PACKAGES设定，一个列表中的所有应用，包括那些设置为dont_delete_data（部分已安装的应用程序的数据目录）将返回。

1.创建 布局文件

activity_main.xml

你可以看到附件中的截图，我们将创建一个列表显示所有已安装的应用程序。

        
     
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snippet_list_row.xml

这个布局是由ListView适配器用于表示应用程序的细节。它显示应用程序图标、应用程序名称和应用程序包。

    
        
         
             
              
          
     
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2.java 类

AllAppsActivity.java

这是用于初始化和列表已安装的应用程序的主要应用程序类。从packagemanage得到应用细节列表是一个耗时的任务，我们将在AsyncTask里面做。同时，类使用自定义适配器“自定义listview applicationadapter”。

package com.javatechig.listapps;import java.util.ArrayList;import java.util.List;import android.app.AlertDialog;import android.app.ListActivity;import android.app.ProgressDialog;import android.content.ActivityNotFoundException;import android.content.DialogInterface;import android.content.Intent;import android.content.pm.ApplicationInfo;import android.content.pm.PackageManager;import android.net.Uri;import android.os.AsyncTask;import android.os.Bundle;import android.view.Menu;import android.view.MenuInflater;import android.view.MenuItem;import android.view.View;import android.widget.ListView;import android.widget.Toast;public class AllAppsActivity extends ListActivity {	private PackageManager packageManager = null;	private List
    
      applist = null;	private ApplicationAdapter listadaptor = null;	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		packageManager = getPackageManager();		new LoadApplications().execute();	}	public boolean onCreateOptionsMenu(Menu menu) {		MenuInflater inflater = getMenuInflater();		inflater.inflate(R.menu.menu, menu);		return true;	}	public boolean onOptionsItemSelected(MenuItem item) {		boolean result = true;		switch (item.getItemId()) {		case R.id.menu_about: {			displayAboutDialog();			break;		}		default: {			result = super.onOptionsItemSelected(item);			break;		}		}		return result;	}	private void displayAboutDialog() {		final AlertDialog.Builder builder = new AlertDialog.Builder(this);		builder.setTitle(getString(R.string.about_title));		builder.setMessage(getString(R.string.about_desc));		builder.setPositiveButton("Know More", new DialogInterface.OnClickListener() {		       public void onClick(DialogInterface dialog, int id) {		    	   Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://stacktips.com"));		    	   startActivity(browserIntent);		    	   dialog.cancel();		       }		   });		builder.setNegativeButton("No Thanks!", new DialogInterface.OnClickListener() {		       public void onClick(DialogInterface dialog, int id) {		            dialog.cancel();		       }		});		builder.show();	}	@Override	protected void onListItemClick(ListView l, View v, int position, long id) {		super.onListItemClick(l, v, position, id);		ApplicationInfo app = applist.get(position);		try {			Intent intent = packageManager					.getLaunchIntentForPackage(app.packageName);			if (null != intent) {				startActivity(intent);			}		} catch (ActivityNotFoundException e) {			Toast.makeText(AllAppsActivity.this, e.getMessage(),					Toast.LENGTH_LONG).show();		} catch (Exception e) {			Toast.makeText(AllAppsActivity.this, e.getMessage(),					Toast.LENGTH_LONG).show();		}	}	private List
     
       checkForLaunchIntent(List
      
        list) {		ArrayList
       
         applist = new ArrayList
        
         ();		for (ApplicationInfo info : list) {			try {				if (null != packageManager.getLaunchIntentForPackage(info.packageName)) {					applist.add(info);				}			} catch (Exception e) {				e.printStackTrace();			}		}		return applist;	}	private class LoadApplications extends AsyncTask
         
           { private ProgressDialog progress = null; @Override protected Void doInBackground(Void... params) { applist = checkForLaunchIntent(packageManager.getInstalledApplications(PackageManager.GET_META_DATA)); listadaptor = new ApplicationAdapter(AllAppsActivity.this, R.layout.snippet_list_row, applist); return null; } @Override protected void onCancelled() { super.onCancelled(); } @Override protected void onPostExecute(Void result) { setListAdapter(listadaptor); progress.dismiss(); super.onPostExecute(result); } @Override protected void onPreExecute() { progress = ProgressDialog.show(AllAppsActivity.this, null, "Loading application info..."); super.onPreExecute(); } @Override protected void onProgressUpdate(Void... values) { super.onProgressUpdate(values); } }}复制代码
         
        
       
      
     
    

ApplicationAdapter.java

package com.javatechig.listapps;import java.util.List;import android.content.Context;import android.content.pm.ApplicationInfo;import android.content.pm.PackageManager;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ImageView;import android.widget.TextView;public class ApplicationAdapter extends ArrayAdapter
    
      {	private List
     
       appsList = null;	private Context context;	private PackageManager packageManager;	public ApplicationAdapter(Context context, int textViewResourceId,			List
      
        appsList) {		super(context, textViewResourceId, appsList);		this.context = context;		this.appsList = appsList;		packageManager = context.getPackageManager();	}	@Override	public int getCount() {		return ((null != appsList) ? appsList.size() : 0);	}	@Override	public ApplicationInfo getItem(int position) {		return ((null != appsList) ? appsList.get(position) : null);	}	@Override	public long getItemId(int position) {		return position;	}	@Override	public View getView(int position, View convertView, ViewGroup parent) {		View view = convertView;		if (null == view) {			LayoutInflater layoutInflater = (LayoutInflater) context					.getSystemService(Context.LAYOUT_INFLATER_SERVICE);			view = layoutInflater.inflate(R.layout.snippet_list_row, null);		}		ApplicationInfo applicationInfo = appsList.get(position);		if (null != applicationInfo) {			TextView appName = (TextView) view.findViewById(R.id.app_name);			TextView packageName = (TextView) view.findViewById(R.id.app_paackage);			ImageView iconview = (ImageView) view.findViewById(R.id.app_icon);			appName.setText(applicationInfo.loadLabel(packageManager));			packageName.setText(applicationInfo.packageName);			iconview.setImageDrawable(applicationInfo.loadIcon(packageManager));		}		return view;	}};复制代码