for (ApplicationInfo info : applicationInfos)简化

这行代码的简化版本是使用传统的 for 循环：

for (int i = 0; i < applicationInfos.size(); i++) {
    ApplicationInfo info = applicationInfos.get(i);
    // 进行相应的操作
}

在使用 for-each 循环时，我们不需要自己去维护循环计数器，也无需手动获取集合中的元素。相反，我们只需要指定集合的类型和对元素的引用，即可轻松地遍历集合中所有元素。

相关问题

ApplicationInfo

### ApplicationInfo in Android Development

#### Overview of ApplicationInfo
In the context of Android development, `ApplicationInfo` represents metadata about an application package that is retrieved from the manifest file. This object contains various properties and flags which provide detailed information regarding how the application should operate within the system environment[^1].

The following attributes are part of this class:

- **packageName**: The name of the package.
- **sourceDir**: Absolute path to the .apk file on disk.
- **publicSourceDir**: Public source directories (for split APKs).
- **dataDir**: Directory where persistent data can be stored by the app.
- **nativeLibraryDir**: Path to native libraries directory.

Additionally, several boolean fields indicate specific characteristics or capabilities such as whether it has code (`hasCode`) or supports small screens (`supportsSmallScreens`). There also exist methods like `loadLabel()`, allowing developers to access human-readable labels defined inside `<application>` tags.

#### Retrieving Information Using PackageManager
Developers often interact with instances of `ApplicationInfo` via the `PackageManager`. By calling appropriate APIs provided by `PackageManager`, one can obtain details concerning installed applications including their icons, names, permissions required, etc., all encapsulated within objects derived from `PackageItemInfo`.

For instance, when querying for packages using `getInstalledApplications(int flags)` method, each result will contain its corresponding `ApplicationInfo` structure filled out based upon what was specified under respective `<application>` elements found during parsing process conducted over `AndroidManifest.xml`.

// Example Code Snippet Showing How To Get An Instance Of ApplicationInfo From Package Name
try {
    String targetPackageName = "com.example.app";
    Context context = getApplicationContext();
    PackageManager pm = context.getPackageManager();
    
    // Retrieve Application Info With Specific Flags Applied For More Detailed Data
    int flagValue = PackageManager.GET_META_DATA;
    ApplicationInfo ai = pm.getApplicationInfo(targetPackageName, flagValue);
} catch (NameNotFoundException e) {
    Log.e("Error", "Failed to find info");
}

--related questions--

1. What other classes extend from PackageItemInfo besides ApplicationInfo?
2. Can you explain more about the role of PackageManager in managing apps' lifecycle events?
3. In what scenarios would someone need to use GET_UNINSTALLED_PACKAGES flag while fetching ApplicationInfo?
4. Is there any difference between accessing ApplicationInfo through Activity versus Service components?

ResolveInfo 和ApplicationInfo

ResolveInfo和ApplicationInfo都是Android中的类，但是它们的作用略有不同。

ResolveInfo类提供了一个关于能够处理特定Intent的组件的信息，它包含了一个Activity、Service或BroadcastReceiver的信息，例如它的名称、包名、Icon等等。ResolveInfo可以通过PackageManager中的queryIntentActivities()、queryIntentServices()、queryBroadcastReceivers()等方法获取。

而ApplicationInfo是一个应用程序的信息，它包含了应用程序的名称、包名、版本、Icon、签名证书等等。在AndroidManifest.xml中声明的组件（Activity、Service、BroadcastReceiver等）都是由ApplicationInfo表示的。可以通过PackageManager中的getPackageInfo()获取一个应用程序的ApplicationInfo。