Questions tagged [android-context]
Interface to global information about an application environment
android-context
1,973
questions
2254
votes
32
answers
817k
views
What is 'Context' on Android?
In Android programming, what exactly is a Context class and what is it used for?
I read about it on the developer site, but I am unable to understand it clearly.
- 23.3k
1106
votes
21
answers
840k
views
Static way to get 'Context' in Android?
Is there a way to get the current Context instance inside a static method?
I'm looking for that way because I hate saving the 'Context' instance each time it changes.
- 27.4k
1029
votes
12
answers
276k
views
What's "tools:context" in Android layout files?
Starting with a recent new version of ADT, I've noticed this new attribute on the layout XML files, for example:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:...
- 116k
741
votes
30
answers
647k
views
Using context in a fragment
How can I get the context in a fragment?
I need to use my database whose constructor takes in the context, but getApplicationContext() and FragmentClass.this don't work so what can I do?
Database ...
- 72.4k
695
votes
28
answers
418k
views
Dialog throwing "Unable to add window — token null is not for an application” with getApplication() as context
My Activity is trying to create an AlertDialog which requires a Context as a parameter. This works as expected if I use:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
However, I am ...
- 7,515
654
votes
10
answers
347k
views
Difference between getContext() , getApplicationContext() , getBaseContext() and "this"
What is the difference between getContext() , getApplicationContext() , getBaseContext() , and "this"?
Though this is simple question I am unable to understand the basic difference between them. ...
- 8,241
501
votes
10
answers
327k
views
Using Application context everywhere?
In an Android app, is there anything wrong with the following approach:
public class MyApp extends android.app.Application {
private static MyApp instance;
public MyApp() {
instance ...
- 56.8k
464
votes
28
answers
352k
views
Calling startActivity() from outside of an Activity context
I have implemented a ListView in my Android application. I bind to this ListView using a custom subclass of the ArrayAdapter class. Inside the overridden ArrayAdapter.getView(...) method, I assign ...
- 10k
449
votes
4
answers
344k
views
getApplication() vs. getApplicationContext()
I couldn't find a satisfying answer to this, so here we go: what's the deal with Activity/Service.getApplication() and Context.getApplicationContext()?
In our application, both return the same object....
- 43.2k
436
votes
16
answers
476k
views
How to get package name from anywhere?
I am aware of the availability of Context.getApplicationContext() and View.getContext(), through which I can actually call Context.getPackageName() to retrieve the package name of an application.
...
- 10.5k
402
votes
7
answers
96k
views
What's the difference between the various methods to get an Android Context?
In various bits of Android code I've seen:
public class MyActivity extends Activity {
public void method() {
mContext = this; // since Activity extends Context
mContext = ...
- 337k
335
votes
18
answers
229k
views
getString Outside of a Context or Activity
I've found the R.string pretty awesome for keeping hardcoded strings out of my code, and I'd like to keep using it in a utility class that works with models in my application to generate output. For ...
- 9,298
280
votes
7
answers
85k
views
When to call activity context OR application context?
I do not fully understand the activity context vs the application context.
As I understand it so far, each is an instance of its class, which means that some programmers recommend you to use this....
- 8,962
271
votes
7
answers
160k
views
Difference between Activity Context and Application Context
This has me stumped, I was using this in Android 2.1-r8 SDK:
ProgressDialog.show(getApplicationContext(), ....);
and also in
Toast t = Toast.makeText(getApplicationContext(),....);
using ...
- 34.3k
212
votes
13
answers
169k
views
How to get a context in a recycler view adapter
I'm trying to use picasso library to be able to load url to imageView, but I'm not able to get the context to use the picasso library correctly.
public class FeedAdapter extends RecyclerView.Adapter&...
- 9,204
210
votes
6
answers
167k
views
Call getLayoutInflater() in places not in activity
What does need to be imported or how can I call the Layout inflater in places other than activity?
public static void method(Context context){
//this doesn't work the getLayoutInflater method ...
- 31.8k
209
votes
15
answers
181k
views
getActivity() returns null in Fragment function
I have a fragment (F1) with a public method like this
public void asd() {
if (getActivity() == null) {
Log.d("yes","it is null");
}
}
and yes when I call it (from ...
- 31.8k
201
votes
20
answers
212k
views
How to get Context in Android MVVM ViewModel
I am trying to implement MVVM pattern in my android app. I have read that ViewModels should contain no android specific code (to make testing easier), however I need to use context for various things (...
- 2,996
180
votes
6
answers
186k
views
How do you obtain a Drawable object from a resource id in android package?
I need to get a Drawable object to display on an image button. Is there a way to use the code below (or something like it) to get an object from the android.R.drawable.* package?
for example if ...
- 6,142
137
votes
4
answers
64k
views
difference and when to use getApplication(), getApplicationContext(), getBaseContext() and someClass.this
I'm new to android and I'm trying to understand the difference between getApplication(), getApplicationContext(), getBaseContext(), getContext() and someClass.this and especially when to use the these ...
- 2,171
136
votes
1
answer
168k
views
get Context in non-Activity class [duplicate]
In an android Application, is there any way to get the context in android in a non-activity class if the activity class name is known?
- 1,813
134
votes
12
answers
212k
views
Using getResources() in non-activity class
I am trying to use getResources method in a non-activity class. How do I get the reference to the "resources" object so that I can access the xml file stored under resources folder?
Example:
...
- 9,165
108
votes
2
answers
49k
views
What is the difference between Activity and Context?
Are Activity and Context the same, or are there differences?
When should I have a method pass an Activity, and when a Context?
- 1,479
98
votes
1
answer
58k
views
getApplicationContext(), getBaseContext(), getApplication(), getParent()
What is the difference between:
getApplicationContext()
getBasecontext()
getApplication()
getParent()
Can you elaborate with one simple example?
- 22k
96
votes
9
answers
319k
views
How to get my activity context?
I don't really get the idea behind how this whole thing works really, so if I have some class A that need the context of a class B which extends Activity, how do i get that context?
I'm searching for ...
- 8,500
88
votes
3
answers
48k
views
Android - Getting context from a Broadcast receiver onReceive() to send to
I basically want to make an intent and pass it to a service from my BroadcastReceiver's onReceive().
So far I always used View.getContext(), but here, I'm stuck.
How exactly can I get the context so ...
- 5,332
87
votes
7
answers
77k
views
Close the current activity when you only have a reference to Context
If I have a reference to Context, is it possible to finish the current activity?
I don't have the reference to current activity.
- 21.5k
86
votes
4
answers
77k
views
getting context in AsyncTask
I am trying to get the context in my AsyncTask of the class called Opciones(this class is the only one that call that task) but I don't know how to do it, I saw some code like this:
protected ...
- 2,595
74
votes
12
answers
115k
views
How to reference the current or main activity from another class
I often find myself needing to access methods that require referencing some activity. For example, to use getWindowManager, I need to access some Activity. But often my code for using these methods is ...
- 28.7k
71
votes
5
answers
119k
views
android - How to get view from context?
I want to get the view or findViewById() from Context?
Or from intent?
I'm trying to reach a specific view in my broadcast receiver and the parameter of onReceive are context and intent.
Well, I ...
- 6,171
71
votes
5
answers
33k
views
Is it possible to get application's context in an Android Library Project?
I would like to get the context of application which has reference/hosted my library at run-time inside one class of my library project. Is it possible? If yes, how?
Thanks
Update
I don't want my ...
- 30k
67
votes
9
answers
112k
views
How to display AlertDialog in a Fragment?
I want to display an alert dialog in my app. I am using fragments. I tried the below code to do this:
AlertDialog ad = new AlertDialog.Builder(context)
.create();
ad.setCancelable(...
- 8,079
67
votes
5
answers
87k
views
Get context inside onClick(DialogInterface v, int buttonId)?
Getting the context inside onClick(View view), the callback for a button's onClickListener(), is easy:
view.getContext()
But I can't figure out how to get the context inside onClick(DialogInterface ...
- 11.4k
66
votes
5
answers
112k
views
How to call getResources() from a class which has no context?
In my application I have many classes and activities. Droid is a class which does not have context. Mygame is a class which extends SurfaceView and implements SurfaceHolder.Callback.
I am creating an ...
- 8,079
62
votes
4
answers
26k
views
Android DataBinding where to get context?
I have TextView for showing time. I want to use Android's DataBinding plugin.
For formatting time I am using DateUtils.formatDateTime(context, int, int) method which takes Context instance. Is it ...
- 14.2k
62
votes
2
answers
33k
views
Android 13 (SDK 33): PackageManager.getPackageInfo(String, int) deprecated. what is the alternative?
Starting from API level 33 the getPackageInfo(String, int) method of PackageManager class is deprecated. Documentation suggests to use getPackageInfo(String, PackageInfoFlags) instead. But that ...
- 6,443
61
votes
4
answers
33k
views
SharedPreferences application context vs activity context
I am using several SharedPreferences to store data in my app.
Some preferences are used in a lot of activites.
I know that the SharedPreferences are internally backed by a map for fast read-access ...
- 1,956
59
votes
3
answers
36k
views
Android Intent Context Confusing
Can somebody explain this to me please :
Intent intent = new Intent(Context, AlarmReceiver.class);
I never understood and I seriously think I never will if somebody doesn't try to explain this to me ...
- 2,058
58
votes
3
answers
129k
views
Android Get Application's 'Home' Data Directory
A simple question, relating to the default 'home' directory when an app writes to the internal memory. By default, any files created are placed by the OS (2.2) in:
/data/data/your.package/files
When ...
- 10.6k
58
votes
5
answers
99k
views
How to use getSystemService in a non-activity class?
I am building an application which triggers an alarm via AlarmManager.
I would like to be able to call the Alarm via it's own non-activity class, but since I am not extending Activity, I don't appear ...
- 1,751
58
votes
6
answers
63k
views
Dagger 2 injecting Android Application Context
I am using Dagger 2 and have it working however I now need access to the Android Application Context.
Its not clear to me how to inject and get access to the context. I have tried to do this as ...
- 1,642
58
votes
6
answers
60k
views
Getting the android context in an adapter
In many of the code samples that I find on the internet the context is obtained in the constructor of an adapter.
This context is used to get an inflater to inflate the views in getView method.
My ...
- 7,888
58
votes
4
answers
39k
views
Best practice to pass Context to non-activity classes?
So, my first major application is almost coded and I'm doing optimizations on my code. The app works fine, but I'm not sure about my way of passing the context to other classes. I don't want to do it ...
- 5,089
54
votes
7
answers
54k
views
What is different between MainActivity.this vs getApplicationContext()
I am trying ProgressDialog. But I am confused.
1. pd=ProgressDialog.show(MainActivity.this, "", "Fething data");
when I do use (MainActivity.this) then it is ok. But
2. pd=...
- 571
52
votes
5
answers
16k
views
Is it safe to save the app context to a static variable in Android?
I know that usage of static variables on Android is quite risky, especially if you reference them to activities. However, if I have a class that extends Application (let's call this class "App"), is ...
- 116k
49
votes
7
answers
62k
views
Needing Context in non-Activity classes
I have some classes within my application that need to call Android functions that require the Context as a parameter.
I don't have it as the class is not a subclass of the Activity class.
What is ...
- 6,783
44
votes
3
answers
61k
views
Get application context from non activity singleton class
In my android project, I have ImageAdapter class in which I pass app context for some further needs.
public class ImageAdapter extends BaseAdapter {
private Context c;
public ImageAdapter(...
- 680
44
votes
1
answer
2k
views
Write/create file within Android Instrumentation context
I have a class that creates (or opens) a file to write some data to it. This class receives a Context in the constructor, saves it in an instance field, and then uses it to call the context....
- 1,491
43
votes
2
answers
30k
views
Difference between getContext() and requireContext() when using fragments
I've been having this doubt since a long time, when I'm working with android fragments and I need to instantiate a Context, or I need to pass a Context as argument for other function, I can choose to ...
- 1,089
43
votes
1
answer
24k
views
Diffinitive rules for using Android's getBaseContext, getApplicationContext or using an Activity's "this"
I've googled this question a lot and have found many differing recommendations on when to use getBaseContext, getApplicationContext or an Activity's own this pointer.
Three rules that come up often ...
- 2,578