Develop Reference

How to apply light(day) theme at run time (programatically) on Android

When the Android device set to dark mode.
But the user wants to see Light mode only on this app.
Is there any idea to handle this?
This code does not work for me
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
none of these codes is working
val config: Configuration = resources.getConfiguration()
config.uiMode = Configuration.UI_MODE_NIGHT_NO
resources.configuration.uiMode= Configuration.UI_MODE_NIGHT_NO
applicationContext.createConfigurationContext(config)
resources.updateConfiguration(config, getResources().getDisplayMetrics())

I would like to see the method too, where you set once for all your activities. But as far I know you have to set in each activity before showing any views.
For reference check this:
http://www.anddev.org/applying_a_theme_to_your_application-t817.html
Edit (copied from that forum):
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Call setTheme before creation of any(!) View.
setTheme(android.R.style.Theme_Dark);
// ...
setContentView(R.layout.main);
}
Edit
If you call setTheme after super.onCreate(savedInstanceState); your activity recreated but if you call setTheme before super.onCreate(savedInstanceState); your theme will set and activity does not recreate anymore
protected void onCreate(Bundle savedInstanceState) {
setTheme(android.R.style.Theme_Dark);
super.onCreate(savedInstanceState);
// ...
setContentView(R.layout.main);
}

ProgressBar setProgress() not working after Activity recreate()

I have a horizontal ProgressBar which is displaying the remaining life in a game. When the life is 0 (ProgressBar progress is 0) the game ends and there is a button RESTART which calls to activity.recreate();. The progress must be shown full again when recreating but it's being shown empty (progress 0).
All is working fine and being recreated correctly but the ProgressBar. The onCreate() method has this lines:
lifeProgressBar = findViewById(R.id.lifeProgressBar);
lifeProgressBar.setMax(4);
lifeProgressBar.setProgress(4);
When recreating the activity, those lines are being called again. Even putting a breakpoint I can see that the progress is 4, but the ProgressBar is being displayed empty, the same as before recreating the activity.
I tried with invalidate, postinvalidate, etc... not worked.
How to solve this?

From recreate documentation:
public void recreate ()
Cause this Activity to be recreated with a new instance. This results
in essentially the same flow as when the Activity is created due to a
configuration change -- the current instance will go through its
lifecycle to onDestroy() and a new instance then created after it.
Here are activity life cycle when activity got recreated:
onSaveInstanceState() // Save current progress of life progress bar (0 in your case)
onDestroy()
onCreate() // You fill full life progress bar
onRestoreInstanceState() // [IMPORTANT] Activity restores previous state and set progress of life progress bar to 0.
This is expected behavior of Android, if you need to fill full life progress bar after activity got recreated, then you need to do it in onRestoreInstanceState().
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lifeProgressBar = findViewById(R.id.lifeProgressBar);
fillFullLifeProgressBar();
}
private void fillFullLifeProgressBar() {
lifeProgressBar.setMax(4);
lifeProgressBar.setProgress(4);
}
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
// Fill full life progress bar here.
fillFullLifeProgressBar();
}

Recreating your activity like this will work for you.
finish();
startActivity(getIntent());
overridePendingTransition(0, 0);

getWindow().setSoftInputMode not working as expected

In my Android project I want the softInputMode for just one fragment to be adjustPan.
Adding the following line to my manifest (inside the activity) works as expected:
android:windowSoftInputMode="adjustPan"
But following lines in my fragment do nothing:
#Override
public void onResume() {
super.onResume();
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
}
#Override
public void onPause() {
super.onPause();
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_UNSPECIFIED);
}
Any ideas why that is and what could be done to fix?

You are setting the soft input mode for the activity, i'm not sure if it will work but try:
myFragment.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
EDIT:
I suppose you are working with the onPause and onResume of the fragment, have yout tried using the ones of the parent activity? The result might be the same thou, because some times they are connected.

Try to also set the android:windowSoftInputMode="adjustPan" in your Manifest. I know it looks redundant to set the soft input mode in the manifest and in your code but that's the only way it worked for me.

Implement in 'onCreate' method of your activity.
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_layout);
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
}

You must do it like:
((AppCompatActivity)getContext()).getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN|WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);

Why do OnCreate should be called only once on the start of Activity?

I would like to know, why OnCreate() is called only once at the start of an activity?
Can we call OnCreate() more than once in the same activity?
If yes, than how can we call it? can anyone give an example?
Thanks a lot!!!

Why would you want to called it again? unless the activity is reconstructed, which is called by system. You cannot call OnCreate manually , it is the same reason why you won't call setContentView() twice. as docs:
onCreate(Bundle) is where you initialize your activity. Most
importantly, here you will usually call setContentView(int) with a
layout resource defining your UI, and using findViewById(int) to
retrieve the widgets in that UI that you need to interact with
programmatically.
Once you finish init your widgets Why would you?
UPDATE
I take some words back, you CAN do this manually but I still don't understand why would this be called. Have you tried Fragments ?
Samplecode:
public class MainActivity extends Activity implements OnClickListener {
private Button btPost;
private Bundle state;
private int counter = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
state = savedInstanceState;
btPost = (Button) findViewById(R.id.btPost);
btPost.setOnClickListener(this);
Toast.makeText(getBaseContext(), " " + counter, Toast.LENGTH_LONG)
.show();
}
#Override
public void onClick(View v) {
counter++;
this.onCreate(state);
}
}

onCreate() method performs basic application startup logic that should happen only once for the entire life of the activity .
Once the onCreate() finishes execution, the system calls the onStart() and onResume() methods in quick succession.
The initialization process consumes lot of resources and to avoid this the activity once created is never completely destroyed but remains non visible to user in background so that once it is bring back to front , reinitialization doesn't happen .

Where you want to call onCreate manually.
Then just do this.
finish();
Intent intent = new Intent(Main.this, Main.class);
startActivity(intent);
finish() calls the current stuff.
And if you are doing somethong getExtra in this activity then do this,
#Override
protected void onSaveInstanceState(Bundle outState) {
outState.putString("key",your_variable);
super.onSaveInstanceState(outState);
}
And add this to your onCreate()
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
if(savedInstanceState != null)
{
your_variable= savedInstanceState.getString("key");
}
}

Why would you want to call onCreate more than once? You will be re-creating the activity. If this is what you need for whatever reason then finish the activity and use an intent to create a new instance of that activity. Otherwise, you have two instances of the activity at the same time. Hope that helps but if that doesn't make sense then add more information as to what you want so we have context

OnCreate is basically use to create your activity (UI). If you have already created your activity then you need not create it again as you have already created.
It is basically used to initialize your activity and to create user interface of your activity. Activity is a visual part which you can use again and again so.. I think your problem is not to recreate activity but to reinitialize all components of your activity. For that purpose you can create a method initialize_act() and call it from anywhere...

#OnCreate is only for initial creation, and thus should only be called once.
If you have any processing you wish to complete multiple times you should put it elsewhere, perhaps in the #OnResume method.

Recently i realized that onCreate is called on every screen orientation change (landscape/portrait). You should be aware of this while planning your initialization process.
Recreation can be suppressed in AndroidManifest.xml:
<activity
android:configChanges="keyboardHidden|orientation"
android:name=".testActivity"
android:label="#string/app_name"></activity>

Activity doesn't show in full screen

I defined a new Activity on my project and I have some trouble with fullScreen.
I defined in the manifest file like this:
<activity android:name=".Test"
android:launchMode="singleInstance" android:screenOrientation="portrait"
android:theme="#android:style/Theme.NoTitleBar.Fullscreen"
.............
>
If I start the activity from another activity, I got the desired full screen. The problem is when I start this activity from a BroadcastReceiver - I need to open this activity inside a BroadcastReceiver something like this:
public void onReceive(Context context, Intent intent) {
Intent test = new Intent(context, Test.class);
test.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(test);
}
I tried like this too:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.test);
}
and no full screen if the activity starts from my BroadcastReciever.
Why I don't get full screen on this case? There is any way to request full screen after the Activity is created and visible?

I fond the issue. There is a method I omitted to add in question text - I didn't thought it's relevant. Because I want this activity to intercept (do not react) home button press, and for this reason I override onAttachedToWindow() method like this:
public void onAttachedToWindow() {
getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}
And here is the issue. Some times, because of this, my activity didn't get full screen. To fix this, I don't know if this is the best way, I added a delay to this code, like this:
public void onAttachedToWindow() {
handler.sendEmptyMessageDelayed(100,100);
super.onAttachedToWindow();
}
and the handler:
public boolean handleMessage(Message msg) {
getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
}
and this solved my issue. I hope this help someone!