本文介绍如何使用Android SDK中的PackageManager类和PackageInfo类来判断特定应用是否已安装在系统中，并提供了一个实用的工具类实现。通过解析应用的Manifest.xml文件，可以获取到应用的详细信息，包括权限、服务、接收者等。实现了一个方法isAppInstalled，通过传入上下文和应用包名参数，判断应用是否已安装。
【0】我们可以使用getPackageManager() 方法来查询安装在系统上的AP.
| java.lang.Object | |
| ↳ | android.content.pm.PackageManager |
 Known Direct Subclasses
|
getPackageManager().
| java.lang.Object | |
| ↳ | android.content.pm.PackageInfo |
Overall information about the contents of a package. This corresponds to all of the information collected from AndroidManifest.xml.
publicActivityInfo[]activities
Array of all<activity>tags included under <application>, or null if there were none. This is only filled in if the flagGET_ACTIVITIESwas set.
publicApplicationInfoapplicationInfo
Information collected from the <application> tag, or null if there was none.
publicConfigurationInfo[]configPreferences
Application specified preferred configuration<uses-configuration>tags included under <manifest>, or null if there were none. This is only filled in if the flagGET_CONFIGURATIONSwas set.
public longfirstInstallTime
The time at which the app was first installed. Units are as percurrentTimeMillis().
public int[]gids
All kernel group-IDs that have been assigned to this package. This is only filled in if the flagGET_GIDSwas set.
publicInstrumentationInfo[]instrumentation
Array of all<instrumentation>tags included under <manifest>, or null if there were none. This is only filled in if the flagGET_INSTRUMENTATIONwas set.
public longlastUpdateTime
The time at which the app was last updated. Units are as percurrentTimeMillis().
publicStringpackageName
The name of this package. From the <manifest> tag's "name" attribute.
publicPermissionInfo[]permissions
Array of all<permission>tags included under <manifest>, or null if there were none. This is only filled in if the flagGET_PERMISSIONSwas set.
publicProviderInfo[]providers
Array of all<provider>tags included under <application>, or null if there were none. This is only filled in if the flagGET_PROVIDERSwas set.
publicActivityInfo[]receivers
Array of all<receiver>tags included under <application>, or null if there were none. This is only filled in if the flagGET_RECEIVERSwas set.
publicFeatureInfo[]reqFeatures
The features that this application has said it requires.
publicString[]requestedPermissions
Array of all<uses-permission>tags included under <manifest>, or null if there were none. This is only filled in if the flagGET_PERMISSIONSwas set. This list includes all permissions requested, even those that were not granted or known by the system at install time.
publicServiceInfo[]services
Array of all<service>tags included under <application>, or null if there were none. This is only filled in if the flagGET_SERVICESwas set.
publicStringsharedUserId
The shared user ID name of this package, as specified by the <manifest> tag'ssharedUserIdattribute.
public intsharedUserLabel
The shared user ID label of this package, as specified by the <manifest> tag'ssharedUserLabelattribute.
publicSignature[]signatures
Array of all signatures read from the package file. This is only filled in if the flagGET_SIGNATURESwas set.
public intversionCode
The version number of this package, as specified by the <manifest> tag'sversionCodeattribute.
publicStringversionName
The version name of this package, as specified by the <manifest> tag'sversionNameattribute.
/**
* Whether the AP was installed
* @param context:the Context
* @param packageName:the ap packageName
* @return
*/
public static boolean isAppInstalled(Context context, String packageName)
{
//获取到一个PackageManager的instance
final PackageManager packageManager = context.getPackageManager();
//PERMISSION_GRANTED = 0
List<PackageInfo> mPackageInfo = packageManager.getInstalledPackages(0);
boolean flag = false;
if(mPackageInfo != null)
{
String tempName = null;
for(int i = 0; i < mPackageInfo.size(); i++)
{
//获取到AP包名
tempName = mPackageInfo.get(i).packageName;
if(tempName != null && tempName.equals(packageName))
{
MyLogger.kLog().i("Package[" + packageName + "]:is installed.");
flag = true;
break;
}
}
}
return flag;
}public abstractList<PackageInfo>getInstalledPackages(int flags)
Return a List of all packages that are installed on the device.
Parameters
| flags | Additional option flags. Use any combination ofGET_ACTIVITIES,GET_GIDS,GET_CONFIGURATIONS,GET_INSTRUMENTATION,GET_PERMISSIONS,GET_PROVIDERS,GET_RECEIVERS,GET_SERVICES,GET_SIGNATURES,GET_UNINSTALLED_PACKAGESto modify the data returned. |
|---|
Returns
- A List of PackageInfo objects, one for each package that is installed on the device. In the unlikely case of there being no installed packages, an empty list is returned. If flag GET_UNINSTALLED_PACKAGES is set, a list of all applications including those deleted with DONT_DELETE_DATA (partially installed apps with data directory) will be returned.
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