Develop Reference

Disable Google Sign in Transition for Single Screen

After signing in with the googleSignIn() method in flutter, there is an undesired transition appearing on the screen (Example : https://i.stack.imgur.com/CWIhL.gif).
This is not a glitch for the Android emulator, it also happens on my physical device.
The only solution I found was to add the following line to the styles.xml to disable the Transition :
<item name="android:windowAnimationStyle">#null</item>
However, I do not want to disable the animations for the whole app. How can I only disable it for the Login Screen ? I do not know what side effects may occur disabling all windowAnimationStyle for the whole app ?

You might be able to create a style for an individual view or a theme for a particular activity or view hierarchy. An example of this is given in the following link: https://gist.github.com/cesarferreira/38bf26a68317ac15f1dc
<!-- Developer should create a style -->
<style name="noAnimTheme" parent="android:Theme">
<item name="android:windowAnimationStyle">#null</item>
</style>
<!-- Then in manifest set it as theme for activity or whole application. -->
<activity android:name=".ui.ArticlesActivity" android:theme="#style/noAnimTheme">
</activity>
More information on Styles and Themes are given here: https://developer.android.com/guide/topics/ui/look-and-feel/themes#Styles

Black screen on starting app

I have noticed that on android versions 6.0+,when someone starting app after login screen and submiting info,black screen appear and you have to wait 3-15 sec depending on devices.
I heard that it could be for heavy loadings,but this app is nothing special it just load listview with few images after login (i had 3 images while tested) so im not sure is it really that heavy plus it only happen on newer versions of android so im not sure what to do.
I can provide whole code or some snippet.
EDIT: I tried with various image sizes (full loaded with big images,and only 1 small image) and it have no effect at all.
Anyone???

Inside your manifest file .
In your Activity tag add this theme.
android:theme="#android:style/Theme.Translucent"
And then you need to extend your respective activity from Activity class.
It will work for sure

For those who face this error in future
<style name="FullscreenTheme" parent="MainTheme">
<item name="windowNoTitle">true</item>
<item name="windowActionBar">false</item>
<item name="android:windowFullscreen">true</item>
<item name="android:windowContentOverlay">#null</item>
<item name="android:windowIsTranslucent">true</item>
</style>

Custom title bar still shows original on startup

I'm using a custom title bar in my app and it all works fine except that when the app starts up, the original (standard) android title bar is shown for a brief time before it is replaced by my custom title bar.
This is not a problem when the app is already loaded in memory because the 'delay' is not apparent but if the app is not already in memory, it is very obvious.
There's nothing special about the code :
requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
setContentView(R.layout.main);
getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.window_title);
I thought about changing the style to have no window title and just include my custom title in the top of the layout but that doesn't seem right.
Thanks for any pointers.

Thomas Devaux has posted a smart solution. It worked in my app
Change the windowTitleBackgroundStyle to use color “#android:color/transparent”.
Also create a style for the text “android:windowTitleStyle” and set its “android:textColor” >to transparent as well.

For completeness to Lluis' answer, here's the full code you need to hide the default-title before the custom-title is initiated:
<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">
<style name="CustomWindowTitleStyle">
<item name="android:textColor">#android:color/transparent</item>
</style>
<style name="CustomTheme" parent="#android:style/Theme.Holo">
<item name="android:windowActionBar">false</item>
<item name="android:windowTitleBackgroundStyle">#android:color/transparent</item>
<item name="android:windowTitleSize">50dp</item>
<item name="android:windowTitleStyle">#style/CustomWindowTitleStyle</item>
</style>
</resources>

add a splash screen activity before the main activity loads, should have enough time for the next one to load properly

Are you able to use an app theme to set a custom title globally for your app? See here for a pretty good example. I had a similar problem and i seem to remember going this route fixed it.

How to set the background screen as Wallpaper all the time?

Currently, I'm using this to show my application background as phone wallpaper.
getWindow().setFlags(WindowManager.LayoutParams.FLAG_SHOW_WALLPAPER,
WindowManager.LayoutParams.FLAG_SHOW_WALLPAPER);
But for some reason when I start my application by pressing the icon. It just shows the activity screen with the icons on the home screen. I didn't use dialog but it looks like a dialog because layout is just set that way. So I just want to show the wallpaper whenever this activity is running. But it only shows the wallpaper only after the next event occurs such as switching to different activity. I already put that code on onCreate() and whenever I do setContentView()..... Is there way to do such thing or there is just no way?

For users of AppCompat, just use the following in your styles.xml, no need for code:
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat">
<item name="android:windowBackground">#android:color/transparent</item>
<item name="android:colorBackgroundCacheHint">#null</item>
<item name="android:windowShowWallpaper">true</item>
<item name="android:windowTranslucentNavigation">true</item>
<item name="android:windowTranslucentStatus">true</item>
</style>

After long search and trial and error. I've found the solution to what I wanted. It was just creating separate themes.xml file and just tweak the Theme.Dialog which is already defined in default android themes.xml. All I did was change the Animation part. Originally in android themes.xml the line looks like this.
<item name="android:windowAnimationStyle">#android:style/Animation.Dialog</item>
but since modifying in android themes.xml doesn't take the effect. I just created my own themes.xml as I said above and just set parent as android:Theme.Dialog. And added a line like this.
<item name="android:windowAnimationStyle">#android:style/Animation</item>
Thanks for the help and I hope this solution helps others.

Use following code -
rl = (RelativeLayout)findViewById(R.id.someid);
//relative layout is my root node in main.xml (yours may be linearlayout)
WallpaperManager wm = WallpaperManager.getInstance(this);
Drawable d = wm.peekDrawable();
rl.setBackgroundDrawable(d);// You can also use rl.setBackgroundDrawable(getWallpaper);

Activity should be transparent, but has black background

My use case is writing an overlay controller activity for a landscape camera preview. I followed the instructions from a couple of tutorials for writing a transparent theme.
So my res/values/style.xml looks like this:
<resources>
<style name="Theme" parent="android:Theme" />
<style name="Theme.Transparent">
<item name="android:windowBackground">#drawable/transparent_background</item>
</style>
<drawable name="transparent_background">#00000000</drawable>
</resources>
The activity snippet:
<activity android:name=".CameraPreview"
android:label="Camera"
android:screenOrientation="landscape"
android:theme="#android:style/Theme.NoTitleBar.Fullscreen">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".Controlls"
android:label="Controlls"
android:screenOrientation="portrait"
android:theme="#android:style/Theme.Translucent">
</activity>
When I start this activity from my root activity, the layout gets drawn correctly, but the background stays black. I tried to use #android:style/Theme.Translucent instead, but this Theme inherits the orientation from the calling activity (landscape) and thats not what I want.
Edit:
The application holding the camera preview is set to landscape view as it does not display the preview correctly in portrait orientation. (see old google bug report)
What I wanted to do was to put an independent activity for user interaction interface in front of the camera surface holder (this activity should be set to 'portrait', or even better to 'sensor')

Here's a somewhat related answer for anyone else that has a similar problem.
tl;dr
Adding a new style where the name is a suffix of an existing style can cause problems (like making transparent activities have a black screen).
Problem:
Our transparent activity background was black after doing a large refactor. (The activity was already using a transparent theme.)
After several hours of going through commits I found what seemed to be the cause of the problem. In our app we use styles like CSS. There was an existing style like this that we applied to a TextView.
<style name="HeadLine.SM.White.MyFontBold">
<item name="android:fontFamily">#font/some_bold_font</item>
</style>
The non-bold variant of the style was added as a style before the bold variant as below.
//This style was added
<style name="HeadLine.SM.White.MyFont">
<item name="android:fontFamily">#font/some_font</item>
</style>
<style name="HeadLine.SM.White.MyFontBold">
<item name="android:fontFamily">#font/some_bold_font</item>
</style>
For some reason, after the non-bold style variant was added all transparent activities had a black screen. When we changed the non-bold variant style name to something else it fixed the problem for us.
Now our styles look like this (I know there are better ways to handle font styles - these styles are a few years old).
<style name="HeadLine.SM.White.MyFontRegular">
<item name="android:fontFamily">#font/some_font</item>
</style>
<style name="HeadLine.SM.White.MyFontBold">
<item name="android:fontFamily">#font/some_bold_font</item>
</style>
Conclusion
It seemed that adding a new style where the name is a suffix of an existing style caused problems. If you're adding a new style make sure the name is not a suffix of an existing style.
We did try cleaning the build, rebuilding, and invalidating Android Studio caches. None of these things solved our problem.

Try the built-in #android:style/Theme.Translucent instead of your custom one, according to this blog post. I haven't tried to do this myself, so I don't know if the technique written about there works or not.

I found out, that another important child element for the style description above is <item name="android:windowIsTranslucent">true</item> was lacking.
Problem:
That child element also causes synchronizing the activity's orientation with the calling one. (same effect as #android:style/Theme.Translucent)

I bumped into the same problem as you describe (regarding translucent background and screen orientation), but in the end I reconciled with the fact that this is just how it works. In fact it actually makes sense that it works this way. I can't think of any screen based system that supports mixing portrait and landscape views, so why should Android?
I guess the general rule is that all visible activities must have the same orientation, regardless of the attributes in the manifest-file. If all are set to "sensor" then they will all change, if one is fixed to portrait or landscape, then the others must follow (and whoever sets it last "wins").
I guess this was just so obvious to the developers that it didn't occur to them to document it :)

Remove and all its done
#Override
public void onAttachedToWindow() {}

Style name is having some effect on the transparent background to be black. I used below one and works fine.
<style name="Theme.AppCompat.Translucent">
<item name="android:windowNoTitle">true</item>
<item name="android:windowBackground">#android:color/transparent</item>
<item name="android:colorBackgroundCacheHint">#null</item>
<item name="android:windowIsTranslucent">true</item>
<item name="android:windowAnimationStyle">#android:style/Animation</item>
</style>
<!-- AndroidManifest.xml -->
<activity android:name=".TranslucentThemeActivity"
android:theme="#style/Theme.AppCompat.Translucent"/>