Android权限 - PermissionsState BasePermission等相关类介绍
1.PermissionInfo
对应的是AndroidManifest(这里的AndroidManifest.xml是指\frameworks\base\core\res\AndroidManifest.xml))文件中permission标签。如在使用READ_CALL_LOG权限的时候，那么系统就可以知道READ_CALL_LOG权限相应的PermissionInfo。
/**
* Information you can retrieve about a particular security permission
* known to the system. This corresponds to information collected from the
* AndroidManifest.xml's <permission> tags.
*/
public class PermissionInfo extends PackageItemInfo implements Parcelable {
public int protectionLevel; //对应的标签为：android:protectionLevel="dangerous|instant"
public @Nullable String group; //权限组，对应的标签为：android:permissionGroup="android.permission-group.UNDEFINED"
......
public @Flags int flags; //对应的标签为：android:permissionFlags="hardRestricted"
public @StringRes int descriptionRes; //对应的标签为：android:description="@string/permdesc_accessFineLocation"
@SystemApi
public @StringRes int requestRes;
@SystemApi
@TestApi
public final @Nullable String backgroundPermission; //对应的标签为：android:backgroundPermission="android.permission.ACCESS_BACKGROUND_LOCATION"
......
}以下为READ_CALL_LOG的权限信息：
相关string的定义
read call log
This app can read your call history. 2.PermissionGroupInfo
特定的权限组信息，在AndroidManifest.xml(这里的AndroidManifest.xml是指\frameworks\base\core\res\AndroidManifest.xml)中的标记为permission-group。如在使用LOCATION权限组的时候，那么系统就可以知道LOCATION权限组相应的PermissionGroupInfo。
/**
* Information you can retrieve about a particular security permission
* group known to the system. This corresponds to information collected from the
* AndroidManifest.xml's <permission-group> tags.
*/
public class PermissionGroupInfo extends PackageItemInfo implements Parcelable {
public @StringRes int descriptionRes; //对应的标签为：android:description="@string/permgroupdesc_location"
@SystemApi
public @StringRes int requestRes; //对应的标签为：android:request="@string/permgrouprequest_location"
@SystemApi
public final @StringRes int requestDetailResourceId; //对应的标签为：android:requestDetail="@string/permgrouprequestdetail_location"
@SystemApi
public final @StringRes int backgroundRequestResourceId; //对应的标签为：android:backgroundRequestDetail="@string/permgroupbackgroundrequestdetail_location"
@SystemApi
public final @StringRes int backgroundRequestDetailResourceId; //对应的标签为：android:backgroundRequestDetail
......
public int priority; //对应的标签为: android:priority="400"
}以下为LOCATION的权限组信息：
相关string的定义：
Location
access this device\'s location
Allow
<b>%1$s </b> to access this device\'s location?
The app will only have access to the location while you\u2019re using the app
Allow
<b>%1$s </b> to access this device\u2019s location <b>all the time</b>?
App currently can access location only while you\u2019re using the app 3.BasePermission
主要用在动态权限中，保存PermissionInfo，及其对应的uid,包名等。
public final class BasePermission {
final String name; // BasePermission名字，实际为packages.xml中标签里面item name,即为每一条permission的名字
// 4.PackageParser.Permission
安装包中解析出来的权限信息,主要包括PermissionInfo及PermissionGroup。
public final static class Permission extends Component implements Parcelable {
@UnsupportedAppUsage
public final PermissionInfo info;
@UnsupportedAppUsage
public boolean tree;
@UnsupportedAppUsage
public PermissionGroup group;
} 5.PackageParser.PermissionGroup
安装包中解析出来的权限组信息，主要是PermissionGroupInfo。
public final static class PermissionGroup extends Component implements Parcelable {
@UnsupportedAppUsage
public final PermissionGroupInfo info;
} 6.PermissionsState
这个类封装了一个包或者一个共享用户的权限。
有两种类型的权限，安装权限(在安装时授予的权限)和运行时权限(在运行时授予的权限)。
安装权限被授予送给设备的所有用户，运行时权限被显式授予特定用户。
权限按每个设备用户保留，例如，一个应用程序可能在设备所有者下授予了某些运行时权限，但在第二用户下没有授予。
这个类还负责跟踪包或共享用户的每个用户的Linux gid。gid是按每个用户为所有授予权限的gid计算的一组gid。
/**
* This class encapsulates the permissions for a package or a shared user.
*
* There are two types of permissions: install (granted at installation)
* and runtime (granted at runtime). Install permissions are granted to
* all device users while runtime permissions are granted explicitly to
* specific users.
*
*
* The permissions are kept on a per device user basis. For example, an
* application may have some runtime permissions granted under the device
* owner but not granted under the secondary user.
*
* This class is also responsible for keeping track of the Linux gids per
* user for a package or a shared user. The gids are computed as a set of
* the gids for all granted permissions' gids on a per user basis.
*
*/
public final class PermissionsState {
/** The permission operation failed. */
public static final int PERMISSION_OPERATION_FAILURE = -1;
/** The permission operation succeeded and no gids changed. */
public static final int PERMISSION_OPERATION_SUCCESS = 0;
/** The permission operation succeeded and gids changed. */
public static final int PERMISSION_OPERATION_SUCCESS_GIDS_CHANGED = 1;
......
@GuardedBy("mLock")
private ArrayMap mPermissions; // 所有权限
private int[] mGlobalGids = NO_GIDS;
private SparseBooleanArray mPermissionReviewRequired;
} 此类非常重要，基本上对于权限的所有具体操作，如授权，取消，判断是否具有某权限，都是在这个类中进行操作的。
7.PermissionsState.PermissionData
private static final class PermissionData {
private final BasePermission mPerm;
private SparseArray mUserStates = new SparseArray<>();
} 8.PermissionsState.PermissionState
public static final class PermissionState {
private final String mName; //权限name
private boolean mGranted; //是否授权了
private int mFlags;
}
用一张图来示例更清晰：
