android - 如何获取运行应用程序的图标并保存在 Array_list 中？

Question

我想让图标运行应用程序并显示在 listView 中。我可以获得应用程序的名称。我会在 ListView 中显示但是我使用以下代码管理器.java

   public class Manager  {
  //other methods


   public ArrayList<Drawable> getListApp()
{
    my_packge_name=new ArrayList<String>();
    my_packge_icon=new ArrayList<Drawable>();

    PackageManager pm = base_context.getPackageManager();;
    ActivityManager am=(ActivityManager) base_context.getSystemService(Context.ACTIVITY_SERVICE);
    List<ActivityManager.RunningAppProcessInfo> runningAppProcessInfo = am.getRunningAppProcesses();
    for (int i = 0; i < runningAppProcessInfo.size(); i++) 
    {
        String s=runningAppProcessInfo.get(i).processName;
        try {
        ApplicationInfo ap= pm.getApplicationInfo(s, PackageManager.GET_META_DATA);

        if( pm.getLaunchIntentForPackage(ap.packageName) != null ){
            String currAppName = pm.getApplicationLabel(ap).toString();
            Drawable icon=pm.getApplicationIcon(ap);

               my_packge_icon.add(icon);
          //  my_packge_name.add(currAppName);

           //This app is a non-system app
}
    return my_packge_icon;
 }

列表.java

protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_manager);
    list=(ListView)findViewById(R.id.listView1);

    arr_icons= new ArrayList<Drawable> (new    Manager(getBaseContext()).getListApp());

    adapter=new Myadapter(getBaseContext());
    list.setAdapter(adapter);

}

在获取 View 中

if(convertView==null)
        {
            Holder=new ViewHolder();
            convertView=myInflater.inflate(R.layout.custom_item_listview,null );
            Holder.title=(TextView)convertView.findViewById(R.id.title);
            Holder.icon=(ImageView)findViewById(R.id.image_icon);
            convertView.setTag(Holder);

        }
        else
        Holder=(ViewHolder) convertView.getTag();

       Holder.icon.setImageDrawable(arr_icons.get(position));

错误:

  Java.lang.NullPointerException.....

当我正确运行所有程序的名称时。但是当我得到这个错误的所有程序图标时。我不知道为什么数组没有初始化。

Answer 1

假设 image_icon 属于 custom_item_listview.xml

 Holder.icon=(ImageView)findViewById(R.id.image_icon);

错了。应该是

 Holder.icon=(ImageView)convertView.findViewById(R.id.image_icon);

喜欢你的TextView