Develop Reference

Why onConfigurationChanged doesn't detect screen rotation?

I'm trying to use onConfigurationChanged to detect screen rotation.
Activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public void onConfigurationChanged(#NonNull Configuration newConfig) {
super.onConfigurationChanged(newConfig);
Toast.makeText(getApplicationContext(), "Screen is rotated!", Toast.LENGTH_SHORT).show();
Log.i("ROTATEAPP", "Screen is rotated...");
}
}
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">
<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.ScreenRotate"
tools:targetApi="31">
<activity
android:name=".MainActivity"
android:configChanges="orientation"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name="android.app.lib_name"
android:value="" />
</activity>
</application>
</manifest>
I rotated the device (Pixel 3 running Android 12) a few times, and didn't see any Toast or log entry. What's wrong here?

animated splash screen doesn't appear

In this project I tried to make an animated splash screen which will appear before going to the main activity, but after I execute, the splash screen does not appear but instead goes directly to the main activity.
how to fix this?
this is my splash activity class
private ImageView container;
private AnimationDrawable animationDrawable;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash)
container = findViewById(R.id.iv_icons);
container.setBackgroundResource(R.drawable.mysplash_animation);
animationDrawable = (AnimationDrawable) container.getBackground();
}
#Override
protected void onResume() {
super.onResume();
animationDrawable.start();
checkAnimationStatus(50, animationDrawable);
}
private void checkAnimationStatus(final int time, final AnimationDrawable animationDrawable) {
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
if (animationDrawable.getCurrent() != animationDrawable.getFrame(animationDrawable.getNumberOfFrames() - 1))
checkAnimationStatus(time, animationDrawable);
else finish();
}
}, time);
}
}
and this is my manifest.xml
<application
android:allowBackup="true"
android:exported="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.AppCompat.NoActionBar">
<activity android:name=".SplashActivity"></activity>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

You have to change this in your manifest(you have to give launcher activity to splashActivity)
<application
android:allowBackup="true"
android:exported="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.AppCompat.NoActionBar">
<activity android:name=".SplashActivity">
// below code you have to add //
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity">
//Remove from here//
</activity>
</application>

Set your Splash Activity as the Launcher activity:
<activity android:name=".MainActivity"></activity>
<activity android:name=".SplashActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />

Please provide intentfilter to SplashActivity
<application
android:allowBackup="true"
android:exported="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.AppCompat.NoActionBar">
<activity android:name=".SplashActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity">
</activity>
</application>

ActivityNotFoundExceptionstarted appearing out of nowhere

Before my application was working fine. I just created a new class (within the same package) and also declared it in the manifest, still I get a ActivityNotFoundException and sometimes NoClassDefFoundException.
TestActivity.java
public class TestActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.order_summary);
}
}
Activity_NewOrder.java
public class Activity_NewOrder extends Activity
try {
//Also tried Intent intent = new Intent(Activity_NewOrder.this, TestActivity.class);
Intent intent = new Intent(getApplicationContext(), TestActivity.class);
startActivity(intent);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
}
AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mypackage">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".Activities.Activity_OrderSummaryNew"
android:configChanges="orientation|keyboardHidden"
android:screenOrientation="landscape" />
<activity
android:name=".Activities.Activity_Login"
android:configChanges="orientation"
android:screenOrientation="landscape">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Activities.Activity_Orders"
android:configChanges="orientation|keyboardHidden"
android:screenOrientation="landscape" />
<activity
android:name=".Activities.Activity_NewOrder"
android:configChanges="orientation|keyboardHidden"
android:screenOrientation="landscape" />
<activity
android:name=".Activities.Activity_OrderHistory"
android:configChanges="orientation|keyboardHidden"
android:screenOrientation="landscape" />
<activity android:name=".Activities.TestActivity" />
</application>
</manifest>

Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference

I'm trying to implement Facebook login button, but i'm receiving these errors when trying to run app:
Error:
FATAL EXCEPTION: AsyncTask #4
Process: , PID: 4633
java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference
at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:746)
at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:774)
at com.facebook.internal.Utility.queryAppSettings(Utility.java:825)
at com.facebook.login.widget.LoginButton$1.run(LoginButton.java:489)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
com.android.vlada.sportisa E/GoogleApiAvailability: Google Play services is invalid. Cannot recover.
Code:
public class MainActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener {
private Button buttonRegistrujSe, buttonPrijaviSeKaoGost, buttonPrijavaRegistrovaniKorisnik;
private LoginButton loginButton;
private CallbackManager callbackManager;
private TextView info;
#Override
protected void onCreate(Bundle savedInstanceState) {
FacebookSdk.sdkInitialize(getApplicationContext());
setContentView(R.layout.activity_main);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FacebookSdk.sdkInitialize(getApplicationContext());
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestEmail()
.build();
GoogleApiClient mGoogleApiClient;
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
.addApi(Auth.GOOGLE_SIGN_IN_API, gso)
.build();
buttonRegistrujSe = (Button) (findViewById(R.id.button_registruj_se));
buttonRegistrujSe.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, RegistrationActivity.class);
startActivity(i);
}
});
buttonPrijaviSeKaoGost = (Button) (findViewById(R.id.button_prijavi_se_kao_gost));
buttonPrijaviSeKaoGost.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i2 = new Intent(MainActivity.this, LoginGostActivity.class);
startActivity(i2);
}
});
buttonPrijavaRegistrovaniKorisnik = (Button) (findViewById(R.id.button_prijava_registrovani_korisnik));
buttonPrijavaRegistrovaniKorisnik.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i3 = new Intent(MainActivity.this, LoginActivity.class);
startActivity(i3);
}
});
callbackManager = CallbackManager.Factory.create();
setContentView(R.layout.activity_main);
info = (TextView)findViewById(R.id.info);
loginButton = (LoginButton)findViewById(R.id.connectWithFbButton);
loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
#Override
public void onSuccess(LoginResult loginResult) {
info.setText(
"User ID: "
+ loginResult.getAccessToken().getUserId()
+ "\n" +
"Auth Token: "
+ loginResult.getAccessToken().getToken()
);
}
#Override
public void onCancel() {
info.setText("Login attempt canceled.");
}
#Override
public void onError(FacebookException e) {
info.setText("Login attempt failed.");
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
callbackManager.onActivityResult(requestCode, resultCode, data);
}
#Override
protected void onDestroy() {
super.onDestroy();
System.exit(0);
}
#Override
public void onConnectionFailed(#NonNull ConnectionResult connectionResult) {
}
}
Layout Code
<com.facebook.login.widget.LoginButton
android:id="#+id/connectWithFbButton"
style="#style/com_facebook_loginview_default_style"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_above="#+id/sign_in_button"
android:layout_centerHorizontal="true"
android:layout_marginBottom="43dp" />
Update: after i deleted duplicate code in MainActivity i'm still receiving the same errors when trying to ran app. I'm attaching Manifest code also as requested so maybe that would help? Thanx
<?xml version="1.0" encoding="utf-8"?>
<!-- To auto-complete the email text field in the login form with the user's emails -->
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.INTERNET" />
<permission
android:name="com.android.vlada.sportisa.Entiteti.maps.permission.MAPS_RECEIVE"
android:protectionLevel="signature" />
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
<uses-permission android:name="com.android.vlada.sportisa.Entiteti.maps.permission.MAPS_RECEIVE" />
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyAVb2JuN-5nbaVkGODivuXPJOF5OeRekzo" />
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="#string/facebook_login" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity android:name=".MainActivity" />
<activity android:name=".SplashActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".RegistrationActivity" />
<activity android:name=".LoginActivity" />
<activity android:name=".BiranjeAktivnosti" />
<activity
android:name=".Trazim"
android:label="#string/title_activity_trazim"
android:theme="#style/AppTheme" />
<activity
android:name=".Organizujem"
android:label="#string/title_activity_organizujem"
android:theme="#style/AppTheme" />
<activity
android:name="com.facebook.FacebookActivity"
android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
android:label="#string/app_name"
android:theme="#android:style/Theme.Translucent.NoTitleBar" />
</application>

Add metadata inside application tag before activities.
What you have now is:
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyAVb2JuN-5nbaVkGODivuXPJOF5OeRekzo" />
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="#string/facebook_login" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity android:name=".MainActivity" />
<activity android:name=".SplashActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
...
</application>
Move metadata inside application tag like this:
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyAVb2JuN-5nbaVkGODivuXPJOF5OeRekzo" />
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="#string/facebook_login" />
<activity android:name=".MainActivity" />
<activity android:name=".SplashActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
...
</application>

Have you added this code in manifest file.
You also need to add the application id like this:
<application android:label="#string/app_name" ...>
...
<meta-data android:name="com.facebook.sdk.ApplicationId" android:value="#string/facebook_app_id"/>
...
</application>

Don't what, but there's an issue with either FacebookActivity name or the support for Gradle Version 2.3.0 is removed. I faced the same issue and with the following I got rid of this.
Replaced <activity> tag
<activity
android:name="com.facebook.FacebookActivity"
android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
android:label="#string/app_name"
android:theme="#android:style/Theme.Translucent.NoTitleBar" />
with the <meta> tag.
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="#string/fb_id" />
EDIT
Also, I have placed this <meta> tag at the bottom of the file below, all the activities, above the closing tag.

Unable to find explicit activity class error

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.exampl.fitindya"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="9"
android:targetSdkVersion="20" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".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>
<!-- Entry for RegisterActivity.class -->
<activity android:name=".RegisterActivity"
android:label="Register New Account"></activity>
</application>
Don't know why this error is appearing and application crashes. please help guys.can there be any problem anywhere else
here is my class file
public class MainActivity extends ActionBarActivity {
Button login_b1;
#Override
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.activity_main);
TextView registerScreen = (TextView) findViewById(R.id.link_to_register);
// Listening to register new account link
registerScreen.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Switching to Register screen
Intent i = new Intent(getApplicationContext(), RegisterActivity.class);
startActivity(i);
}
});
}
}

Place this code below the register Activity. I guess that should be the error
<intent-filter>
<action android:name="android.intent.action.DEFAULT" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>