獲取已安裝軟件包(InstalledPackages)及其活動(Activity)的信息.

跟上一篇文章"Android 的功能編號(feature ID), PackageManager 和 getSystemAvailableFeatures()"差不多, 這個程序也是通過PackageManager獲得一些系統信息: 已安裝軟件包(InstalledPackages)及其活動(Activity).

首先程序會調用PackageManager.getInstalledPackages()獲取已安裝軟件包的信息, 並以列表視圖(ListView)形式顯示, 當點擊任何軟件包時, 會再以列表視圖(ListView)顯示其活動(Activity), 再當點擊任何活動時, 會以Toast顯示其名稱.




另一值得注意的是本程序只有一個列表活動(ListActivity), 一個列表視圖(ListView), 但有機會應用到兩個適配器上; 這可以在onListItemClick()中檢查ListView.getAdapter()從而辨認現在所使用的適配器.

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
 android:id="@+id/currentview"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  />
<Button
 android:id="@+id/reload"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:text="Reload InstalledPackages"
 />
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@android:id/empty"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="No Data" />
</LinearLayout>

AndroidInstalledPackages.java

package com.AndroidInstalledPackages;

import java.util.List;

import android.app.ListActivity;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidInstalledPackages extends ListActivity {
 
 List<PackageInfo> PackageInfoList;
 ArrayAdapter<PackageInfo> PackageArrayAdapter;
 ActivityInfo[] ActivityInfoArray;
 ArrayAdapter<ActivityInfo> ActivityInfoAdapter;
 
 TextView currentView;
 Button buttonReload;
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       currentView = (TextView)findViewById(R.id.currentview);
       buttonReload = (Button)findViewById(R.id.reload);
      
       loadPackageInfoList();
      
       buttonReload.setOnClickListener( new Button.OnClickListener(){

   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    loadPackageInfoList();
   }
       });
      
   }
  
   private void loadPackageInfoList(){
    PackageInfoList = getPackageManager().getInstalledPackages(PackageManager.GET_ACTIVITIES);
       PackageArrayAdapter = new ArrayAdapter<PackageInfo>(this, R.layout.list, PackageInfoList);
       setListAdapter(PackageArrayAdapter);
      
       currentView.setText("getInstalledPackages");
       buttonReload.setEnabled(false);
   }

 @Override
 protected void onListItemClick(ListView l, View v, int position, long id) {
  // TODO Auto-generated method stub
  //super.onListItemClick(l, v, position, id);
  
  if (l.getAdapter()==PackageArrayAdapter){
   ActivityInfoArray = PackageInfoList.get(position).activities;
   if (ActivityInfoArray!=null)
   {
    ActivityInfoAdapter = new ArrayAdapter<ActivityInfo>(this, R.layout.list, ActivityInfoArray);
    setListAdapter(ActivityInfoAdapter);
    
          currentView.setText("activities");
          buttonReload.setEnabled(true);
   }
   else{
    Toast.makeText(this, "Empty", Toast.LENGTH_LONG).show();
   }
  }
  else{
   CharSequence info = ActivityInfoArray[position].name;
   Toast.makeText(this, info, Toast.LENGTH_LONG).show();
  }

 }
  
}