ApplicationInfo: Information you can retrieve about a particular application. This corresponds to information collected from the AndroidManifest.xml's application
根据AndroidManifest.xml文件中的标签“application” 检索到特定的应用，包含activity,broadcast,service,provider。
ResolveInfo: Information that is returned from resolving an intent against an IntentFilter. This partially corresponds to information collected from the AndroidManifest.xml's intent
根据AndroidManifest.xml文件中的标签“ intent” 检索到特定的应用。
PackageManager: Class for retrieving various kinds of information related to the application packages that are currently installed on the device.
这个类关联了所有已经安装在手机上的应用，可以利用这个类的对象获取上面两种信息。
1 代码： 2 3 PackageManager manager = getPackageManager(); 4 5 //Return a List of all application packages that are installed on the device. 获取所有已经安装的应用的信息。 6 List< ApplicationInfo> appList = manager.getInstalledApplications(PackageManager.GET.UNINSTALLED_PAKAGES); 7 8 // Retrieve all activities that can be performed for the given intent.仅仅是获取所有符合指定intent-filter的activity 9 10 Intent intent = new Intent(Intent.A CTION_MAIN,null); 11 intent.addCategory(Intent.CATEGORY_LAUNCHER); 12 List< ResolveInfo> activityList = manager.queryIntentActivities(intent,0);
拿到上面信息后，可以得到应用的icon ,label等。