I want to show my custom floating button on all screen in my app without putting it in each activity.
Do we have some Global Activity like put a code once will show the Custom View all screen and hide/remove when app killed
I tried lot of things like Screen Overlay display over all apps
Please check code here - How to display custom view on all screen in android from my library
I've never tried to do it the Java/Kotlin way. But have you considered using Fragments?
You can declare xml layout and code for one Activity with a FrameLayout container and an FAB. The container holds all your screens and they switch between each other in the container. The FAB is on top and therefore will be displayed no matter the screen.
The Activity has a reference to any screen that might be displayed in it, so the FAB can behave accordingly.
Not sure if this helps. Perhaps if I see some pictures, I could suggest better.
Related Read:
Creating a fragment: here
Fragment Transactions: here
So I have this activity that creates 4 fragments for me, which are a bottom navigation bar.
when I change to dark mode or light mode, the fragments reset and take me back to the "main fragment" which is basically home in the bottom navigation bar.
so my question is how do I stay in the tab I was in while changing UI mode? while of course changing the UI mode of the fragments as well
The best aproach is to let activity recreate itself with its fragments, some configuration changes might be required to show correct UI. And its always possible that your user will move your app to the background, system will kill it after a while and then when your user will go back to it - you will be back with your problem of recreation. I am talking about it to prevent you from using hacks like configChanges in androidmanifest which prevent Activity recreation on configuration change event.
But back to the main point:
when configuration change destroys your Activity, fragments will be automatically recreated when new instance of Activity will be created. But its up to you to save some of its state. I am not sure how your UI and code looks like. The very basic way to save and restore state (like active tab in your question) is to use: Activity.onSaveInstanceState(Bundle) / Activity.onCreate(savedInstanceState: Bundle?) and Fragment.onSaveInstanceState(Bundle)/Fragment.onCreate(savedInstanceState: Bundle?) mechanism. You save relevant variables in bundles in onSaveInstanceState, and later in onCreate restore this state using savedInstanceState variable, but only if its non null - which happens when Activity is created for the first time.
This is a broad topic, you can find more on this here:
https://developer.android.com/topic/libraries/architecture/saving-states
https://developer.android.com/guide/fragments/saving-state
The app I'm working on shows some sensitive information that must not be shown on the "Recent Tasks" screen when stopping the app by pressing the home button.
I'd like to blur the sensitive data in the screenshot or show the app logo instead.
I am aware of the following approaches but they don't fit my requirements:
Setting the actvitie's android:excludeFromRecents to true in the manifiest prevents the app from being shown at all in the recent tasks. This would disrupt the user experience.
Using FLAG_SECURE results in a blank card on the recents tasks screen. (How do I prevent Android taking a screenshot when my app goes to the background?) I don't like the blank screen. However, I'll stick to this solution if there is no workaround.
Overriding onCreateThumbnail seems like the ideal solution but, unfortunately, doesn't work as it's currently not invoked by the OS :( (https://code.google.com/p/android/issues/detail?id=29370)
And then there are some workarounds that I tried out but that didn't work as hoped:
Start a new activity that shows the app logo in onPause so that it's screenshot is shown instead of the actual activitie's one. But the new activity takes too long to open and it disrupts the user experience.
Set the activitie's content view to an image of the app logo in onPause. That seemed like a great solution to me. Unfortunately, the screenshot for the recent tasks screen is taken at an unspecified time. During testing the app logo quickly appears before the app is closed when pressing 'Home' but the resulting screenshot shows the activity a short time before that.
Removing the sensitive data from the widgets (e.g. textView.setText("")) has the same problem of screenshot timing just mentioned.
Any alternative ideas or solutions to the listed workarounds?
I looked into this a couple of months ago for the same purpose as you.
Unfortunately, I had to conclude that it is simply not possible. I dug through the android source code and confirmed it.
There is no callbacks or methods from android that allows you to customize it (that works anyway). Besides FLAG_SECURE, this part of the code does not accept any input or change.
OnPause and similar lifecycle methods are called too late (the screenshot is taken already). All lifecycle methods that would hint that you're about to go into the background runs too late.
The image you see in the recent tasks is an actual screenshot - and thus isn't affected by changes you do (too late) to your view. That means you can't modify your view just-in-time (like making it invisible, replacing with something else, adding SECURE_FLAG, or any other obstruction of the view). As an aside, these images can be found on an emulator at /data/system_ce/0/recent_images.
The only exception is using FLAG_SECURE, which will prevent the screenshot from being taken of your application. I experimented with setting this FLAG in onPause and removing it in onResume, however as mentioned already these lifecycle methods runs after the screenshot is taken already, and thus had absolutely no effect.
As discussed in How to change the snapshot shown by recent apps list? there used to be a callback that you could use to customize the thumbnail: onCreateThumbnail. However, this does not work and it is never called. To be clear, the callback is still there, it is simply never called by the OS. The fact that it stopped working is poorly documented, but apparently was silently deprecated/removed in 4.0.3
As for the thumbnail itself, it is a screenshot taken serverside. It is taken before onPause is called (or in fact before any callbacks indicating that your activity is about to go into the background is called).
When your app does go into the background, your actual view is animated (to get that zoom-out transition). That animation can be affected through changes you do in onPause (if you're fast enough that is) (I experimented with setting opacity to 0 on the window among other things). This will however only affect the animation. When the animation is finished, the view is replaced by the screenshot taken earlier.
Also see these questions that discuss this:
When does Android take its recent apps switcher screenshot?
Show custom application image in task manager on ICS or JB
Android never call method onCreateThumbnail
Currently (28/10/2020) is impossibile customizing app thumbnail in recent apps screen.
As explained by #Dellkan in the previous answer, the onCreateThumbnail method is not called anymore by the OS.
Unfortunately, also the suggestion to create a kind of launcher/splash screen without the FLAG_SECURE flag to let the app take a screenshot of that activity is not working, because the screenshot is taken on the activity you see and not at the launch of the app.
You cannot even customize the color of window background when using FLAG_SECURE as reported here.
How about implementing a layout overlay on top of your entire activity?
Make it transparent, it's click-through by default, so no negative impact on UX while in use.
In onPause() set a half-transparent, blurred image as the background of that layout, the data will be scrambled behind it. In onResume() change the background to fully transparent again. Voila.
It might be faster than other types of overlays. The positive side effect is, if you do the unblurring as a short animation effect when the user goes back (with a proper library that uses C++ instead of Java), it might even look cool and the users wouldnt even mind seeing it.
I haven't tried this myself, but it's something you haven't tried yet.
Since onPause is called to late, I use WindowFocusChangeListener to observe when the Fragment loses focus. At this moment we can hide all view which show sensitive data:
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
view.getViewTreeObserver().addOnWindowFocusChangeListener(new ViewTreeObserver.OnWindowFocusChangeListener() {
#Override
public void onWindowFocusChanged(boolean hasFocus) {
// hide sensitive data when window moves to background (before system screenshot is captured)
myViewWithSensitiveData.setVisibility(hasFocus ? View.VISIBLE : View.INVISIBLE);
}
});
There is a way to customize it. You need your Activities with sensitive data to FLAG_SECURE in onCreate before you setContentView. Then you need an empty Activity, which renders whatever you want to have as the customized thumbnail. This usually is some sort of splash screen. This new Activity needs to be the launcher and is the only Activity not FLAG_SECURE. This Activity is launched and in onResume starts your actual Activity with the sensitive data.
Android OS will take a screenshot of that new Activity at the beginning of your App. Unfortunately the users will also see this Activity for a short moment. Since every other Activity is FLAG_SECURE, Android OS will use the only available screenshot it made at the beginning.
Was looking for a solution and found some dirty things in case you don't want to use 'FLAG_SECURE'. It doesn't give a nice picture but protects data and doesn't prevent making screenshots for the user while they are in the app.
protected void onPause () {
this.getWindow().getDecorView().getRootView().setScaleX((float)200);
this.getWindow().getDecorView().getRootView().setScaleY((float)200);
super.onPause();
}
protected void onResume () {
this.getWindow().getDecorView().getRootView().setScaleX((float)1);
this.getWindow().getDecorView().getRootView().setScaleY((float)1);
super.onResume();
}
I think this can only achieve through BroadCastReceiver but there is no receiver present. So therefore you first disable default screenshot functionality in android and then implementing your own functionality to take screenshot and before taking screenshot you should blur your secure information.
I spent a few hours to get the same look of ActionMode during selecting text inside Dialog as in eg Fragment. If I select text in Fragment, ActionMode, it looks like it is from from Lollipop if in Dialog like on 4.3.
What is most annoying is that sometimes it is showing normal icons (grey) but sometimes they are white so you don't know what you can click. I don't have more ideas, I tried everything I found:
Custom style of: actionModeStyle
Specified in main style: actionModeBackground (doesn't work any of other options too)
Custom ActionMode.Callback (this one works but is showing under default ActionMode)
Changed theme of context passed to AlertDialog.Builder working but its not same as in eg fragment.
App compiled with API21, target 21, tested on SGS3. Compiling with API20 doesn't change anything, so I don't know how it is possible that ActionMode changed look to new design. S3 works on stock system 4.3.
Screenshots
In fragment
Dialog - with white icons, sometimes they are grey
Dialog - with themedContext passed to Builder
Is it possible to get the same look inside Dialog as is normal in Fragment? Or everywhere as in Dialog? Before one of the last updates I always had ActionMode as on 2nd image, but showing correctly.
I have the following problem:
When I start my activity, its default background is set to white. I can change it in onCreate method. If I use this method to change the background, I have something like 2 seconds of white background every time I start the activity.
Is there any way to have background that I chose (for example black) from the beginning of application life?
The best way to handle this would be to modify the Activity's Theme. See: Themes.
Essentially, you should be able to set the background in a custom theme, which would be loaded before any calls to set views.
Edit -
The question has been edited slightly, so the previous answer really only applies to setting the background prior to the call of onCreate. If instead you want something to show while your app loads, you could create a special Theme for the initial Activity, and set that in the Manifest.