belongs to Maven artifact com.android.support:support-compat:28.0.0-alpha1
ContextCompat
public
class
ContextCompat
extends Object
java.lang.Object | |
↳ | android.support.v4.content.ContextCompat |
Known Direct Subclasses |
Known Indirect Subclasses |
Helper for accessing features in Context
.
Summary
Protected constructors | |
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ContextCompat()
This class should not be instantiated, but the constructor must be visible for the class to be extended (ex. |
Public methods | |
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static
int
|
checkSelfPermission(Context context, String permission)
Determine whether you have been granted a particular permission. |
static
Context
|
createDeviceProtectedStorageContext(Context context)
Return a new Context object for the current Context but whose storage APIs are backed by device-protected storage. |
static
File
|
getCodeCacheDir(Context context)
Returns the absolute path to the application specific cache directory on the filesystem designed for storing cached code. |
static
int
|
getColor(Context context, int id)
Returns a color associated with a particular resource ID
Starting in |
static
ColorStateList
|
getColorStateList(Context context, int id)
Returns a color state list associated with a particular resource ID. |
static
File
|
getDataDir(Context context)
Returns the absolute path to the directory on the filesystem where all private files belonging to this app are stored. |
static
Drawable
|
getDrawable(Context context, int id)
Returns a drawable object associated with a particular resource ID. |
static
File[]
|
getExternalCacheDirs(Context context)
Returns absolute paths to application-specific directories on all external storage devices where the application can place cache files it owns. |
static
File[]
|
getExternalFilesDirs(Context context, String type)
Returns absolute paths to application-specific directories on all external storage devices where the application can place persistent files it owns. |
static
File
|
getNoBackupFilesDir(Context context)
Returns the absolute path to the directory on the filesystem similar to
|
static
File[]
|
getObbDirs(Context context)
Returns absolute paths to application-specific directories on all external storage devices where the application's OBB files (if there are any) can be found. |
static
<T>
T
|
getSystemService(Context context, Class<T> serviceClass)
Return the handle to a system-level service by class. |
static
String
|
getSystemServiceName(Context context, Class<?> serviceClass)
Gets the name of the system-level service that is represented by the specified class. |
static
boolean
|
isDeviceProtectedStorage(Context context)
Indicates if the storage APIs of this Context are backed by device-encrypted storage. |
static
boolean
|
startActivities(Context context, Intent[] intents, Bundle options)
Start a set of activities as a synthesized task stack, if able. |
static
boolean
|
startActivities(Context context, Intent[] intents)
Start a set of activities as a synthesized task stack, if able. |
static
void
|
startActivity(Context context, Intent intent, Bundle options)
Start an activity with additional launch information, if able. |
static
void
|
startForegroundService(Context context, Intent intent)
startForegroundService() was introduced in O, just call startService for before O. |
Inherited methods | |
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From
class
java.lang.Object
|
Protected constructors
ContextCompat
ContextCompat ()
This class should not be instantiated, but the constructor must be visible for the class to be extended (ex. in ActivityCompat).
Public methods
checkSelfPermission
int checkSelfPermission (Context context, String permission)
Determine whether you have been granted a particular permission.
Parameters | |
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context |
Context |
permission |
String : The name of the permission being checked. |
Returns | |
---|---|
int |
PERMISSION_GRANTED if you have the
permission, or PERMISSION_DENIED if not. |
See also:
createDeviceProtectedStorageContext
Context createDeviceProtectedStorageContext (Context context)
Return a new Context object for the current Context but whose storage APIs are backed by device-protected storage.
On devices with direct boot, data stored in this location is encrypted with a key tied to the physical device, and it can be accessed immediately after the device has booted successfully, both before and after the user has authenticated with their credentials (such as a lock pattern or PIN).
Because device-protected data is available without user authentication, you should carefully limit the data you store using this Context. For example, storing sensitive authentication tokens or passwords in the device-protected area is strongly discouraged.
If the underlying device does not have the ability to store device-protected and credential-protected data using different keys, then both storage areas will become available at the same time. They remain as two distinct storage locations on disk, and only the window of availability changes.
Each call to this method returns a new instance of a Context object; Context objects are not shared, however common state (ClassLoader, other Resources for the same configuration) may be so the Context itself can be fairly lightweight.
Prior to API 24 this method returns
null
, since device-protected storage is not available.
Parameters | |
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context |
Context |
Returns | |
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Context |
See also:
getCodeCacheDir
File getCodeCacheDir (Context context)
Returns the absolute path to the application specific cache directory on
the filesystem designed for storing cached code. On devices running
LOLLIPOP
or later, the system will delete
any files stored in this location both when your specific application is
upgraded, and when the entire platform is upgraded.
This location is optimal for storing compiled or optimized code generated by your application at runtime.
Apps require no extra permissions to read or write to the returned path, since this path lives in their private storage.
Parameters | |
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context |
Context |
Returns | |
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File |
The path of the directory holding application code cache files. |
getColor
int getColor (Context context, int id)
Returns a color associated with a particular resource ID
Starting in M
, the returned
color will be styled for the specified Context's theme.
Parameters | |
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context |
Context |
id |
int : The desired resource identifier, as generated by the aapt
tool. This integer encodes the package, type, and resource
entry. The value 0 is an invalid identifier. |
Returns | |
---|---|
int |
A single color value in the form 0xAARRGGBB. |
Throws | |
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Resources.NotFoundException |
if the given ID does not exist. |
getColorStateList
ColorStateList getColorStateList (Context context, int id)
Returns a color state list associated with a particular resource ID.
Starting in M
, the returned
color state list will be styled for the specified Context's theme.
Parameters | |
---|---|
context |
Context |
id |
int : The desired resource identifier, as generated by the aapt
tool. This integer encodes the package, type, and resource
entry. The value 0 is an invalid identifier. |
Returns | |
---|---|
ColorStateList |
A color state list, or null if the resource could not be
resolved. |
Throws | |
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Resources.NotFoundException |
if the given ID does not exist. |
getDataDir
File getDataDir (Context context)
Returns the absolute path to the directory on the filesystem where all
private files belonging to this app are stored. Apps should not use this
path directly; they should instead use getFilesDir()
,
getCacheDir()
, getDir(String, int)
, or
other storage APIs on Context
.
The returned path may change over time if the calling app is moved to an adopted storage device, so only relative paths should be persisted.
No additional permissions are required for the calling app to read or write files under the returned path.
Parameters | |
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context |
Context |
Returns | |
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File |
See also:
getDrawable
Drawable getDrawable (Context context, int id)
Returns a drawable object associated with a particular resource ID.
Starting in LOLLIPOP
, the
returned drawable will be styled for the specified Context's theme.
Parameters | |
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context |
Context |
id |
int : The desired resource identifier, as generated by the aapt tool.
This integer encodes the package, type, and resource entry.
The value 0 is an invalid identifier. |
Returns | |
---|---|
Drawable |
Drawable An object that can be used to draw this resource. |
getExternalCacheDirs
File[] getExternalCacheDirs (Context context)
Returns absolute paths to application-specific directories on all external storage devices where the application can place cache files it owns. These files are internal to the application, and not typically visible to the user as media.
This is like getCacheDir()
in that these files will be
deleted when the application is uninstalled, however there are some
important differences:
- External files are not always available: they will disappear if the user mounts the external storage on a computer or removes it.
- There is no security enforced with these files.
External storage devices returned here are considered a permanent part of the device, including both emulated external storage and physical media slots, such as SD cards in a battery compartment. The returned paths do not include transient devices, such as USB flash drives.
An application may store data on any or all of the returned devices. For
example, an app may choose to store large files on the device with the
most available space, as measured by StatFs
.
Starting in KITKAT
, no permissions
are required to write to the returned paths; they're always accessible to
the calling app. Before then,
WRITE_EXTERNAL_STORAGE
is required to
write. Write access outside of these paths on secondary external storage
devices is not available. To request external storage access in a
backwards compatible way, consider using android:maxSdkVersion
like this:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18" />
The first path returned is the same as
getExternalCacheDir()
. Returned paths may be null
if a storage device is unavailable.
Parameters | |
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context |
Context |
Returns | |
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File[] |
getExternalFilesDirs
File[] getExternalFilesDirs (Context context, String type)
Returns absolute paths to application-specific directories on all external storage devices where the application can place persistent files it owns. These files are internal to the application, and not typically visible to the user as media.
This is like getFilesDir()
in that these files will be
deleted when the application is uninstalled, however there are some
important differences:
- External files are not always available: they will disappear if the user mounts the external storage on a computer or removes it.
- There is no security enforced with these files.
External storage devices returned here are considered a permanent part of the device, including both emulated external storage and physical media slots, such as SD cards in a battery compartment. The returned paths do not include transient devices, such as USB flash drives.
An application may store data on any or all of the returned devices. For
example, an app may choose to store large files on the device with the
most available space, as measured by StatFs
.
Starting in KITKAT
, no permissions
are required to write to the returned paths; they're always accessible to
the calling app. Before then,
WRITE_EXTERNAL_STORAGE
is required to
write. Write access outside of these paths on secondary external storage
devices is not available. To request external storage access in a
backwards compatible way, consider using android:maxSdkVersion
like this:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18" />
The first path returned is the same as
getExternalFilesDir(String)
. Returned paths may be
null
if a storage device is unavailable.
Parameters | |
---|---|
context |
Context |
type |
String |
Returns | |
---|---|
File[] |
getNoBackupFilesDir
File getNoBackupFilesDir (Context context)
Returns the absolute path to the directory on the filesystem similar to
getFilesDir()
. The difference is that files placed under this
directory will be excluded from automatic backup to remote storage on
devices running LOLLIPOP
or later.
No permissions are required to read or write to the returned path, since this path is internal storage.
Parameters | |
---|---|
context |
Context |
Returns | |
---|---|
File |
The path of the directory holding application files that will not be automatically backed up to remote storage. |
See also:
getObbDirs
File[] getObbDirs (Context context)
Returns absolute paths to application-specific directories on all external storage devices where the application's OBB files (if there are any) can be found. Note if the application does not have any OBB files, these directories may not exist.
This is like getFilesDir()
in that these files will be
deleted when the application is uninstalled, however there are some
important differences:
- External files are not always available: they will disappear if the user mounts the external storage on a computer or removes it.
- There is no security enforced with these files.
External storage devices returned here are considered a permanent part of the device, including both emulated external storage and physical media slots, such as SD cards in a battery compartment. The returned paths do not include transient devices, such as USB flash drives.
An application may store data on any or all of the returned devices. For
example, an app may choose to store large files on the device with the
most available space, as measured by StatFs
.
Starting in KITKAT
, no permissions
are required to write to the returned paths; they're always accessible to
the calling app. Before then,
WRITE_EXTERNAL_STORAGE
is required to
write. Write access outside of these paths on secondary external storage
devices is not available. To request external storage access in a
backwards compatible way, consider using android:maxSdkVersion
like this:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18" />
The first path returned is the same as getObbDir()
.
Returned paths may be null
if a storage device is unavailable.
Parameters | |
---|---|
context |
Context |
Returns | |
---|---|
File[] |
See also:
getSystemService
T getSystemService (Context context, Class<T> serviceClass)
Return the handle to a system-level service by class.
Parameters | |
---|---|
context |
Context : Context to retrieve service from. |
serviceClass |
Class : The class of the desired service. |
Returns | |
---|---|
T |
The service or null if the class is not a supported system service. |
See also:
getSystemServiceName
String getSystemServiceName (Context context, Class<?> serviceClass)
Gets the name of the system-level service that is represented by the specified class.
Parameters | |
---|---|
context |
Context : Context to retrieve service name from. |
serviceClass |
Class : The class of the desired service. |
Returns | |
---|---|
String |
The service name or null if the class is not a supported system service. |
See also:
isDeviceProtectedStorage
boolean isDeviceProtectedStorage (Context context)
Indicates if the storage APIs of this Context are backed by device-encrypted storage.
Parameters | |
---|---|
context |
Context |
Returns | |
---|---|
boolean |
startActivities
boolean startActivities (Context context, Intent[] intents, Bundle options)
Start a set of activities as a synthesized task stack, if able.
In API level 11 (Android 3.0/Honeycomb) the recommended conventions for app navigation using the back key changed. The back key's behavior is local to the current task and does not capture navigation across different tasks. Navigating across tasks and easily reaching the previous task is accomplished through the "recents" UI, accessible through the software-provided Recents key on the navigation or system bar. On devices with the older hardware button configuration the recents UI can be accessed with a long press on the Home key.
When crossing from one task stack to another post-Android 3.0, the application should synthesize a back stack/history for the new task so that the user may navigate out of the new task and back to the Launcher by repeated presses of the back key. Back key presses should not navigate across task stacks.
startActivities provides a mechanism for constructing a synthetic task stack of multiple activities. If the underlying API is not available on the system this method will return false.
Parameters | |
---|---|
context |
Context : Start activities using this activity as the starting context |
intents |
Intent : Array of intents defining the activities that will be started. The element
length-1 will correspond to the top activity on the resulting task stack. |
options |
Bundle : Additional options for how the Activity should be started.
See startActivity(Intent, android.os.Bundle) |
Returns | |
---|---|
boolean |
true if the underlying API was available and the call was successful, false otherwise |
startActivities
boolean startActivities (Context context, Intent[] intents)
Start a set of activities as a synthesized task stack, if able.
In API level 11 (Android 3.0/Honeycomb) the recommended conventions for app navigation using the back key changed. The back key's behavior is local to the current task and does not capture navigation across different tasks. Navigating across tasks and easily reaching the previous task is accomplished through the "recents" UI, accessible through the software-provided Recents key on the navigation or system bar. On devices with the older hardware button configuration the recents UI can be accessed with a long press on the Home key.
When crossing from one task stack to another post-Android 3.0, the application should synthesize a back stack/history for the new task so that the user may navigate out of the new task and back to the Launcher by repeated presses of the back key. Back key presses should not navigate across task stacks.
startActivities provides a mechanism for constructing a synthetic task stack of multiple activities. If the underlying API is not available on the system this method will return false.
Parameters | |
---|---|
context |
Context : Start activities using this activity as the starting context |
intents |
Intent : Array of intents defining the activities that will be started. The element
length-1 will correspond to the top activity on the resulting task stack. |
Returns | |
---|---|
boolean |
true if the underlying API was available and the call was successful, false otherwise |
startActivity
void startActivity (Context context, Intent intent, Bundle options)
Start an activity with additional launch information, if able.
In Android 4.1+ additional options were introduced to allow for more
control on activity launch animations. Applications can use this method
along with ActivityOptionsCompat
to use these animations when
available. When run on versions of the platform where this feature does
not exist the activity will be launched normally.
Parameters | |
---|---|
context |
Context : Context to launch activity from. |
intent |
Intent : The description of the activity to start. |
options |
Bundle : Additional options for how the Activity should be started.
May be null if there are no options. See
ActivityOptionsCompat for how to build the Bundle
supplied here; there are no supported definitions for
building it manually.
|
startForegroundService
void startForegroundService (Context context, Intent intent)
startForegroundService() was introduced in O, just call startService for before O.
Parameters | |
---|---|
context |
Context : Context to start Service from. |
intent |
Intent : The description of the Service to start. |
Interfaces
Classes