I started a project in Android Studio and apparently, the Theme was Theme.NameOfProject.NoActionBar.
This is causing a the following error :
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.weoutdoor/com.example.weoutdoor.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.appcompat.app.ActionBar.setTitle(java.lang.CharSequence)' on a null object reference
The project themes.xml :
<resources xmlns:tools="http://schemas.android.com/tools">
<!-- Base application theme. -->
<style name="Theme.WeOutdoor" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
<!-- Primary brand color. -->
<item name="colorPrimary">#color/purple_500</item>
<item name="colorPrimaryVariant">#color/purple_700</item>
<item name="colorOnPrimary">#color/white</item>
<!-- Secondary brand color. -->
<item name="colorSecondary">#color/teal_200</item>
<item name="colorSecondaryVariant">#color/teal_700</item>
<item name="colorOnSecondary">#color/black</item>
<!-- Status bar color. -->
<item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
<!-- Customize your theme here. -->
</style>
<style name="Theme.WeOutdoor.NoActionBar">
<item name="windowActionBar">true</item>
<item name="windowNoTitle">true</item>
</style>
<style name="Theme.WeOutdoor.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />
<style name="Theme.WeOutdoor.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />
And the AndroidManifest.xml :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.weoutdoor">
<application
android:allowBackup="true"
android:dataExtractionRules="#xml/data_extraction_rules"
android:fullBackupContent="#xml/backup_rules"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.WeOutdoor.AppBarOverlay"
tools:targetApi="31">
<activity
android:name=".RegisterActivity"
android:exported="false" />
<activity
android:name=".MainActivity"
android:exported="true"
android:theme="#style/Theme.WeOutdoor.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".UserProfileActivity"
android:exported="true"
android:theme="#style/Theme.WeOutdoor.AppBarOverlay">
</activity>
<activity android:name=".LoginActivity"
android:exported="true"
android:theme="#style/Theme.WeOutdoor.AppBarOverlay">
</activity>
</application>
I tried to change the style parent and theme to ThemeOverlay.AppCompat.Dark.ActionBar
but every time i try to use the code getSupportActionBar().setTitle("WeOutdoor");
I get the mentioned error above.
After trying to apply some of the suggestions in the answers to this post I ended up with a new error :
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
Currently my themes is as following :
<resources xmlns:tools="http://schemas.android.com/tools">
<!-- Base application theme. -->
<style name="MyTheme"
parent="Theme.MaterialComponents.DayNight.DarkActionBar">
<item name="windowActionBar">true</item>
And my AndroidMenifest.xml :
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.weoutdoor">
<application
android:allowBackup="true"
android:dataExtractionRules="#xml/data_extraction_rules"
android:fullBackupContent="#xml/backup_rules"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/MyTheme"
tools:targetApi="31">
<activity
android:name=".RegisterActivity"
android:theme="#style/MyTheme"
android:exported="false" />
<activity
android:name=".MainActivity"
android:exported="true"
android:theme="#style/MyTheme">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".UserProfileActivity"
android:exported="true"
android:theme="#style/MyTheme">
</activity>
<activity android:name=".LoginActivity"
android:exported="true"
android:theme="#style/MyTheme">
</activity>
</application>
Keep in mind that in each activity.java i use getSupportActionBar();
My loginActivity that i highlighted in the error :
public class LoginActivity extends AppCompatActivity {
private EditText editTextLoginEmail, editTextLoginPwd;
private ProgressBar progressBar;
private FirebaseAuth authProfile;
private static final String TAG = "LoginActivity";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.login_activity);
getSupportActionBar();
editTextLoginEmail = findViewById(R.id.editText_login_email);
editTextLoginPwd = findViewById(R.id.editText_login_password);
progressBar = findViewById(R.id.progressBar);
authProfile = FirebaseAuth.getInstance();
//Login Tab
Button buttonLogin = findViewById(R.id.button_login);
buttonLogin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String textEmail = editTextLoginEmail.getText().toString();
String textPwd = editTextLoginPwd.getText().toString();
if(TextUtils.isEmpty(textEmail)){
Toast.makeText(LoginActivity.this, "Please enter your email", Toast.LENGTH_SHORT).show();
editTextLoginEmail.setError("Email is required");
editTextLoginEmail.requestFocus();
} else if (!Patterns.EMAIL_ADDRESS.matcher(textEmail).matches()){
Toast.makeText(LoginActivity.this, "Please re-enter your email", Toast.LENGTH_SHORT).show();
editTextLoginEmail.setError("Valid Email is required");
editTextLoginEmail.requestFocus();
} else if (TextUtils.isEmpty(textPwd)){
Toast.makeText(LoginActivity.this, "Please enter your password", Toast.LENGTH_SHORT).show();
editTextLoginPwd.setError("Password is required");
editTextLoginPwd.requestFocus();
} else {
progressBar.setVisibility(View.VISIBLE);
loginUser (textEmail, textPwd);
}
}
});
It would be obvious in loginActivity.java that some lines were commented out and were causing the NPE.
All corrected and ActionBar is working fine.
You're trying to use a ThemeOverlay, which isn't the same as a full Theme. But, honestly, just stick with the NoActionBar theme and create your own toolbar at the top. It's just a layout containing a TextView for the title and some ImageButtons for icons.
It takes 7-10 seconds, I want to know there is a way to reduce the time. Before I installed the splash screen, the home page is loaded in 2-3 seconds. I have installed react-native-splash-screen package and configured the android files automatically by using #bam.tech/react-native-make.
Never tried on a real device, if you want to know.
MainActivity.java
package com.myApp;
import android.os.Bundle;
import org.devio.rn.splashscreen.SplashScreen;
import com.facebook.react.ReactActivity;
public class MainActivity extends ReactActivity {
/**
* Returns the name of the main component registered from JavaScript. This is used to schedule
* rendering of the component.
*/
#Override
protected void onCreate(Bundle savedInstanceState) {
SplashScreen.show(this, R.style.SplashScreenTheme);
super.onCreate(savedInstanceState);
}
#Override
protected String getMainComponentName() {
return "myApp";
}
}
AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.myApp">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:name=".MainApplication"
android:label="#string/app_name"
android:icon="#mipmap/ic_launcher"
android:allowBackup="false"
android:theme="#style/AppTheme">
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:configChanges="keyboard|keyboardHidden|orientation|screenSize|uiMode"
android:launchMode="singleTask"
android:windowSoftInputMode="adjustResize">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.facebook.react.devsupport.DevSettingsActivity" />
</application>
</manifest>
splashscreen.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#color/splashprimary" />
<item>
<bitmap
android:gravity="center"
android:src="#drawable/splash_image" />
</item>
</layer-list>
styles.xml
<resources>
<style name="SplashScreenTheme" parent="SplashScreen_SplashTheme">
<item name="colorPrimaryDark">#color/splashprimary</item>
<item name="android:statusBarColor">#color/app_bg</item>
</style>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="android:textColor">#000000</item>
<!-- Add the following line to set the default status bar color for all the app. -->
<item name="android:statusBarColor">#color/app_bg</item>
<!-- Add the following line to set the default status bar text color for all the app
to be a light color (false) or a dark color (true) -->
<item name="android:windowLightStatusBar">false</item>
<!-- Add the following line to set the default background color for all the app. -->
<item name="android:windowBackground">#color/app_bg</item>
</style>
</resources>
Try adding this in Style.xml
<item name="android:windowDisablePreview">true</item>
This will remove the white screen which appears in the start.
So I have a very simple project with just a few images. I have created a landscape variation, and changed the position of the images.
The problem is, that when running the project on an emulator or device, the default landscape layout is used instead of the variant.
If its run while the emulator is in the landscape position, then it does use the variant, but messes up the portrait.
The only other thing that I've changed is the styles.xml to have:
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
as the App Theme.
I'm fairly new to Android Dev. so it could be something fairly simple.
Any help is greatly appreciated.
Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.test.test">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:configChanges="orientation|screenSize|keyboardHidden" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
What it should look like:
https://i.stack.imgur.com/UXQCd.png
What it shouldn't look like:
https://i.stack.imgur.com/dS54W.png
I found a solution.
This involves keeping the line:
android:configChanges="orientation|screenSize|keyboardHidden" >
In MainActivity.java just add a onConfigurationChanged function like so:
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Checks the orientation of the screen
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
//retrieving resources for the variations
setContentView(R.layout.activity_main);
} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
//retrieving resources for the variations
setContentView(R.layout.activity_main);
}
}
That's the best solution I could come up with. There might be a better way, as this seems a bit redundant.
I have followed a tutorial which shows you how to create a simple action bar at the top of the page, but when I complete it and open the action bar; it opens at the bottom like an options menu, as opposed to being at the top? Whereas I want it to open at the top like in the tutorial:
http://www.androidhive.info/2013/11/android-working-with-action-bar/
Any advice will be helpful:
XML:
<?xml version="1.0" encoding="utf-8"?>
<
menu xmlns:android="http://schemas.android.com/apk/res/android" >
<!-- Search, should appear as action button -->
<item android:id="#+id/action_search"
android:icon="#drawable/whitecog"
android:title="#string/title"
android:showAsAction="ifRoom" />
<!-- Settings, should always be in the overflow -->
<item android:id="#+id/action_settings"
android:title="#string/action_settings"
android:showAsAction="never" />
<!-- Check updates -->
<item android:id="#+id/action_check_updates"
android:icon="#drawable/whitecog"
android:title="#string/action_check_updates"
android:showAsAction="never" />
</menu>
Java:
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main_activity_actions, menu);
return super.onCreateOptionsMenu(menu);
}
Thanks,
Callum
Upon request here is the manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.application"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.application.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.application.DisplayMessageActivity"
android:label="#string/title_activity_display_message" >
</activity>
<activity
android:name="com.example.application.ShowTeamsChosen"
android:label="#string/title_activity_show_teams_chosen" >
</activity>
</application>
</manifest>
Also I am running off 4.4.2
If you have a physical menu button it is completely normal that the overflow menu opens at the bottom.
All devices with physical menu button - today it is mostly Samsung devices - do not have the overflow menu at the top right. This was default before Honeycomb, but it has been deprecated since then. There are only a few OEM that still resist this notion - like Samsung which I already mentioned.
For those devices that still have them the ActionBar will default back to the old behaviour and will not display the new hamburger overflow menu.
To make it stay at the top of the screen, remove
android:uiOptions="splitActionBarWhenNarrow
From your activity definition in your manifest file.
I've developed a simple demo application with a splash screen a map and some regular screens.
I have an action bar at the top that contains a logo. It all looks fine on my phone (Galaxy s1 I9000 V2.3) but when i test it on Galaxy s2 v4 the action bar appears also in the splash screen and in the map screen.
The spalsh and map activity are not even inheriting from ActionBarActivity so how is that possible and how can i make it go away?
Manifest:
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:theme="#style/Theme.AppCompat.Light" >
<activity
android:name=".HomeActivity"
android:icon="#drawable/android_logo"
android:label=""
android:logo="#drawable/android_logo" >
<!--
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
-->
</activity>
<activity
android:name=".MapActivity"
android:label="" >
</activity>
<activity
android:name=".PackageActivity"
android:icon="#drawable/android_logo"
android:label=""
android:logo="#drawable/android_logo" >
</activity>
<activity
android:name=".SplashActivity"
android:label="" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
MapActivity definition (it's a long one so i included just the definition):
public class MapActivity extends FragmentActivity implements LocationListener
Splash Activity:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
public class SplashActivity extends Activity{
private static final long SPLASH_DISPLAY_LENGTH = 2000;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
new Handler().postDelayed(new Runnable(){
#Override
public void run() {
Intent mainIntent = new Intent(SplashActivity.this,HomeActivity.class);
SplashActivity.this.startActivity(mainIntent);
SplashActivity.this.finish();
}
}, SPLASH_DISPLAY_LENGTH);
}
}
As you are asking about how to hide in a certain activity, this is what you need :
getSupportActionBar().hide();
Apply the following in your Theme for the Activity in AndroidManifest.xml:
<activity android:name=".Activity"
android:label="#string/app_name"
android:theme="#android:style/Theme.NoTitleBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
1.Go to your manifest.xml file.
2.Find the activity tag for which you want to hide your ActionBar and then add ,
android:theme="#style/Theme.AppCompat.NoActionBar"
<activity
android:name=".MainActivity"
android:theme="#style/Theme.AppCompat.NoActionBar"
>
If you want to get full screen without actionBar and Title.
Add it in style.xml
<style name="AppTheme.NoActionBar" parent="Theme.AppCompat.Light.DarkActionBar">
<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>
<item name="android:windowFullscreen">true</item>
</style>
and use the style at activity of manifest.xml.
<activity ....
android:theme="#style/AppTheme.NoActionBar" > ......
</activity>
The ActionBar usually exists along Fragments so from the Activity you can hide it
getActionBar().hide();
getActionBar().show();
and from the Fragment you can do it
getActivity().getActionBar().hide();
getActivity().getActionBar().show();
This works for me! Put this in your Activity in manifests
<activity
// ...
android:theme="#style/Theme.AppCompat.Light.NoActionBar"
// ...
</activity>
You can also make your custom theme in styles.xml like this:
<style name="Theme.MyCustomTheme" parent="#style/Theme.AppCompat.Light.NoActionBar">
<item name = "android:windowActionBar">false</item>
<item name = "android:windowNoTitle">true</item>
// more custom...
</style>
Hope this help.
If you were using Theme.AppCompat.Light, a better equivalent would be Theme.AppCompat.Light.NoActionBar.
I found that using Theme.AppCompat.NoTitleBar caused my button text to be invisible so I am using Theme.AppCompat.Light.NoActionBar.
<activity android:name=".Activity"
android:label="#string/app_name"
android:theme="#android:style/Theme.AppCompat.Light.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
To hide the ActionBar add this code into java file.
ActionBar actionBar = getSupportActionBar();
actionBar.hide();
You can use Low Profile mode
See here
Just search for SYSTEM_UI_FLAG_LOW_PROFILE that also dims the navigation buttons if they are present of screen.
Apply the following in your Theme for the Activity in AndroidManifest.xml:
<activity android:name=".DashboardActivity"
android:theme="#style/AppFullScreenTheme">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Then Apply the following in your Style in style.xml
<style name="AppFullScreenTheme" parent="Theme.AppCompat.Light.NoActionBar">
<item name="android:windowNoTitle">true</item>
<item name="android:windowActionBar">false</item>
<item name="android:windowFullscreen">true</item>
<item name="android:windowContentOverlay">#null</item>
</style>
The above answers would help with the ActionBar thing. To add to it, use the following code in case you are using the Splash Screen:
Use this before you set the content view:
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
Just to clarify, here's how you do it:
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
This would make your screen a full screen, i.e remove the top bar where you see the network bar, etc
#Override
public void onResume() {
super.onResume();
getSupportActionBar().hide();
}
#Override
public void onStop() {
super.onStop();
getSupportActionBar().show();
}
For selectively hiding Actionbar in activities:
Add the following code to onCreate (preferably on the last line of the function)
Kotlin:
supportActionBar?.hide()
Java:
getSupportActionBar().hide();
This works in API 27
In the styles.xml replace code to the following....
<resources>
<!-- No Action Bar -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">#color/colorPrimary</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="colorAccent">#color/colorAccent</item>
</style>
</resources>
Then in the files (eg. activity_list.xml) in which you do want to have a toolbar put the following code.
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:background="#color/colorPrimary"/>
If you have problems switch to linear layout (because that is what this code is tested on)
From here:
Beginning with Android 3.0 (API level 11), all activities that use the default theme have an ActionBar as an app bar. However, app bar features have gradually been added to the native ActionBar over various Android releases. As a result, the native ActionBar behaves differently depending on what version of the Android system a device may be using. By contrast, the most recent features are added to the support library's version of Toolbar, and they are available on any device that can use the support library.
So one option is to disable ActionBar completely (in the app manifest.xml file) and then add Toolbar in every page that needs an ActionBar.
(follow the above link for step-by-step explanation)
Add New Style in your style.xml
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">#color/colorPrimary</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="colorAccent">#color/colorAccent</item>
</style>
<style name="LoginTheme" parent="Theme.AppCompat.Light.NoActionBar">
<item name="colorPrimary">#color/colorPrimary</item>
<item name="colorPrimaryDark">#color/colorPrimaryDark</item>
<item name="colorAccent">#color/colorAccent</item>
</style>
and then add following line in your manifest
<activity android:name=".Login"
android:label="#string/app_name"
android:theme="#style/LoginTheme"
>
If you activity extends AppCompatActivity then you can add this line
super.getSupportActionBar().hide(); before setContentView()
Replace AndroidManifest.xml
android:theme="#style/FullscreenTheme"
to
android:theme="#style/Theme.Design.NoActionBar"
Check for padding attribute if the issue still exists after changing theme.
Padding Issue creating a white space on top of fragment window / app window
Once you remove the padding - top value automatically the white space is removed.
First cheek MainActivity for activity tag,Like -
public class MainActivity extends AppCompatActivity
Then goto menifest xml file and write-
android:theme="#style/Theme.AppCompat.Light.NoActionBar"
in activity tag