I am making app which on portrait mode shows fragmentA (containing Listview) and when in Landscape mode, it shows fragmentA and fragmentB(Listview and its corresponding description).It keeps on crashing,my hunch says either there is a fault in if-else condition in MainActivity or problem is in communication pattern.I request Everyone to please Help. Here is my MainActivity.xml
package com.example.prince.fragment_modularui2;
import android.content.Intent;
import android.content.res.Resources;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity implements FragmentA.Communicator{
String s;
Resources r=getResources();
String[] a=r.getStringArray(R.array.descr);
FragmentA fa;
FragmentB fb;
FragmentManager manager;
@Override
protected void onCreate (Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
manager=getSupportFragmentManager();
//fa always present
fa= (FragmentA) manager.findFragmentById(R.id.fragment);
fb= (FragmentB) manager.findFragmentById(R.id.fragment2);
fa.setCommunicator(this);
}
@Override
public void respond(int data) {
Intent i=new Intent(this,AnotherActivity.class);
i.putExtra("index",data);
startActivity(i);
}
}
here is activity_main.xml in Portrait
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.example.prince.fragment_modularui2.FragmentA"
android:id="@+id/fragment"
></fragment>
</LinearLayout>
activity_main in landscape
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<fragment
android:id="@+id/fragment"
android:name="com.example.prince.fragment_modularui2.FragmentA"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true" />
<fragment
android:id="@+id/fragment2"
android:name="com.example.prince.fragment_modularui2.FragmentB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentTop="true" />
</LinearLayout>
Rest of the code is https://github.com/AlmightyHeathcliff/Fragment_ModularUi2
The stackTrace is
07-18 09:45:09.252 1974-1974/? D/AndroidRuntime: >>>>>> START com.android.internal.os.RuntimeInit uid 0 <<<<<<
07-18 09:45:09.254 1974-1974/? D/AndroidRuntime: CheckJNI is OFF
07-18 09:45:09.289 1974-1974/? W/art: Unexpected CPU variant for X86 using defaults: x86
07-18 09:45:09.301 1974-1974/? D/ICU: No timezone override file found: /data/misc/zoneinfo/current/icu/icu_tzdata.dat
07-18 09:45:09.316 1974-1974/? E/memtrack: Couldn't load memtrack module (No such file or directory)
07-18 09:45:09.316 1974-1974/? E/android.os.Debug: failed to load memtrack module: -2
07-18 09:45:09.317 1974-1974/? I/Radio-JNI: register_android_hardware_Radio DONE
07-18 09:45:09.325 1974-1974/? D/AndroidRuntime: Calling main entry com.android.commands.pm.Pm
07-18 09:45:09.330 1974-1974/? I/art: System.exit called, status: 0
07-18 09:45:09.330 1974-1974/? I/AndroidRuntime: VM exiting with result code 0.
07-18 09:45:09.333 1974-1982/? W/MessageQueue: Handler (android.os.Handler) {f6bbfb3} sending message to a Handler on a dead thread
java.lang.IllegalStateException: Handler (android.os.Handler) {f6bbfb3} sending message to a Handler on a dead thread
at android.os.MessageQueue.enqueueMessage(MessageQueue.java:543)
at android.os.Handler.enqueueMessage(Handler.java:643)
at android.os.Handler.sendMessageAtTime(Handler.java:612)
at android.os.Handler.sendMessageDelayed(Handler.java:582)
at android.os.Handler.post(Handler.java:338)
at android.os.ResultReceiver$MyResultReceiver.send(ResultReceiver.java:57)
at com.android.internal.os.IResultReceiver$Stub.onTransact(IResultReceiver.java:58)
at android.os.Binder.execTransact(Binder.java:565)
07-18 09:45:09.972 1993-1993/? D/AndroidRuntime: >>>>>> START com.android.internal.os.RuntimeInit uid 0 <<<<<<
07-18 09:45:09.976 1993-1993/? D/AndroidRuntime: CheckJNI is OFF
07-18 09:45:10.012 1993-1993/? W/art: Unexpected CPU variant for X86 using defaults: x86
07-18 09:45:10.015 1993-1993/? D/ICU: No timezone override file found: /data/misc/zoneinfo/current/icu/icu_tzdata.dat
07-18 09:45:10.049 1993-1993/? E/memtrack: Couldn't load memtrack module (No such file or directory)
07-18 09:45:10.049 1993-1993/? E/android.os.Debug: failed to load memtrack module: -2
07-18 09:45:10.050 1993-1993/? I/Radio-JNI: register_android_hardware_Radio DONE
07-18 09:45:10.059 1993-1993/? D/AndroidRuntime: Calling main entry com.android.commands.pm.Pm
07-18 09:45:10.064 1993-2001/? W/MessageQueue: Handler (android.os.Handler) {f6bbfb3} sending message to a Handler on a dead thread
java.lang.IllegalStateException: Handler (android.os.Handler) {f6bbfb3} sending message to a Handler on a dead thread
at android.os.MessageQueue.enqueueMessage(MessageQueue.java:543)
at android.os.Handler.enqueueMessage(Handler.java:643)
at android.os.Handler.sendMessageAtTime(Handler.java:612)
at android.os.Handler.sendMessageDelayed(Handler.java:582)
at android.os.Handler.post(Handler.java:338)
at android.os.ResultReceiver$MyResultReceiver.send(ResultReceiver.java:57)
at com.android.internal.os.IResultReceiver$Stub.onTransact(IResultReceiver.java:58)
at android.os.Binder.execTransact(Binder.java:565)
07-18 09:45:10.064 1993-1993/? I/art: System.exit called, status: 0
07-18 09:45:10.064 1993-1993/? I/AndroidRuntime: VM exiting with result code 0.
07-18 09:45:13.487 2005-2005/? D/AndroidRuntime: >>>>>> START com.android.internal.os.RuntimeInit uid 0 <<<<<<
07-18 09:45:13.491 2005-2005/? D/AndroidRuntime: CheckJNI is OFF
07-18 09:45:13.569 2005-2005/? W/art: Unexpected CPU variant for X86 using defaults: x86
07-18 09:45:13.575 2005-2005/? D/ICU: No timezone override file found: /data/misc/zoneinfo/current/icu/icu_tzdata.dat
07-18 09:45:13.708 2009-2009/? D/AndroidRuntime: >>>>>> START com.android.internal.os.RuntimeInit uid 0 <<<<<<
07-18 09:45:13.715 2009-2009/? D/AndroidRuntime: CheckJNI is OFF
07-18 09:45:13.760 2005-2005/? E/memtrack: Couldn't load memtrack module (No such file or directory)
07-18 09:45:13.760 2005-2005/? E/android.os.Debug: failed to load memtrack module: -2
07-18 09:45:13.761 2005-2005/? I/Radio-JNI: register_android_hardware_Radio DONE
07-18 09:45:13.776 2005-2005/? D/AndroidRuntime: Calling main entry com.android.commands.wm.Wm
07-18 09:45:13.814 2009-2009/? W/art: Unexpected CPU variant for X86 using defaults: x86
07-18 09:45:13.825 2009-2009/? D/ICU: No timezone override file found: /data/misc/zoneinfo/current/icu/icu_tzdata.dat
07-18 09:45:13.833 2005-2005/? D/AndroidRuntime: Shutting down VM
07-18 09:45:13.839 2005-2019/? W/art: Thread attaching while runtime is shutting down: Binder:2005_2
07-18 09:45:13.839 2005-2019/? I/AndroidRuntime: NOTE: attach of thread 'Binder:2005_2' failed
07-18 09:45:13.891 2009-2009/? E/memtrack: Couldn't load memtrack module (No such file or directory)
07-18 09:45:13.891 2009-2009/? E/android.os.Debug: failed to load memtrack module: -2
07-18 09:45:13.892 2009-2009/? I/Radio-JNI: register_android_hardware_Radio DONE
07-18 09:45:13.903 2009-2009/? D/AndroidRuntime: Calling main entry com.android.commands.am.Am
07-18 09:45:13.909 765-1149/system_process I/ActivityManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.prince.fragment_modularui2/.MainActivity} from uid 0 on display 0
07-18 09:45:13.919 2009-2009/? D/AndroidRuntime: Shutting down VM
07-18 09:45:13.993 765-1021/system_process W/ActivityManager: Slow operation: 75ms so far, now at startProcess: returned from zygote!
07-18 09:45:13.993 765-1021/system_process W/ActivityManager: Slow operation: 75ms so far, now at startProcess: done updating battery stats
07-18 09:45:13.993 765-1021/system_process W/ActivityManager: Slow operation: 75ms so far, now at startProcess: building log message
07-18 09:45:13.993 765-1021/system_process I/ActivityManager: Start proc 2027:com.example.prince.fragment_modularui2/u0a115 for activity com.example.prince.fragment_modularui2/.MainActivity
07-18 09:45:13.993 765-1021/system_process W/ActivityManager: Slow operation: 75ms so far, now at startProcess: starting to update pids map
07-18 09:45:13.993 765-1021/system_process W/ActivityManager: Slow operation: 75ms so far, now at startProcess: done updating pids map
07-18 09:45:13.993 765-1021/system_process W/ActivityManager: Slow operation: 75ms so far, now at startProcess: done starting proc!
07-18 09:45:14.003 2027-2027/? I/art: Late-enabling -Xcheck:jni
07-18 09:45:14.004 2027-2027/? W/art: Unexpected CPU variant for X86 using defaults: x86
07-18 09:45:14.258 500-757/? D/gralloc_vbox86: gralloc_alloc: format 1 and usage 0x933 imply creation of host color buffer
07-18 09:45:14.784 2027-2027/com.example.prince.fragment_modularui2 W/System: ClassLoader referenced unknown path: /data/app/com.example.prince.fragment_modularui2-1/lib/x86
07-18 09:45:14.813 2027-2027/com.example.prince.fragment_modularui2 I/InstantRun: starting instant run server: is main process
07-18 09:45:14.814 2027-2027/com.example.prince.fragment_modularui2 V/InstantRun: Starting server socket listening for package com.example.prince.fragment_modularui2 on android.net.LocalSocketAddress@8989009
07-18 09:45:14.814 2027-2027/com.example.prince.fragment_modularui2 V/InstantRun: Started server for package com.example.prince.fragment_modularui2
07-18 09:45:14.903 2027-2027/com.example.prince.fragment_modularui2 D/AndroidRuntime: Shutting down VM
07-18 09:45:14.904 2027-2027/com.example.prince.fragment_modularui2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.prince.fragment_modularui2, PID: 2027
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.prince.fragment_modularui2/com.example.prince.fragment_modularui2.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2567)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
at android.content.ContextWrapper.getResources(ContextWrapper.java:86)
at android.view.ContextThemeWrapper.getResourcesInternal(ContextThemeWrapper.java:127)
at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:121)
at android.support.v7.app.AppCompatActivity.getResources(AppCompatActivity.java:549)
at com.example.prince.fragment_modularui2.MainActivity.<init>(MainActivity.java:12)
at java.lang.Class.newInstance(Native Method)
at android.app.Instrumentation.newActivity(Instrumentation.java:1078)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2557)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
07-18 09:45:14.907 765-1021/system_process W/ActivityManager: Force finishing activity com.example.prince.fragment_modularui2/.MainActivity
07-18 09:45:15.031 500-505/? D/gralloc_vbox86: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer
07-18 09:45:15.058 500-505/? D/gralloc_vbox86: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer
07-18 09:45:15.115 500-505/? D/gralloc_vbox86: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer
07-18 09:45:15.232 765-1842/system_process I/OpenGLRenderer: Initialized EGL, version 1.4
07-18 09:45:15.232 765-1842/system_process D/OpenGLRenderer: Swap behavior 1
07-18 09:45:15.429 765-779/system_process W/ActivityManager: Activity pause timeout for ActivityRecord{b0310c2 u0 com.example.prince.fragment_modularui2/.MainActivity t693 f}
07-18 09:45:15.431 765-779/system_process I/ActivityManager: Killing 1353:android.process.media/u0a10 (adj 906): empty #17
07-18 09:45:15.432 765-779/system_process I/WindowManager: Failed to capture screenshot of Token{7756ed3 ActivityRecord{b0310c2 u0 com.example.prince.fragment_modularui2/.MainActivity t693 f}} appWin=Window{7f1e54b u0 Starting com.example.prince.fragment_modularui2} drawState=1
07-18 09:45:15.448 765-786/system_process I/Choreographer: Skipped 70 frames! The application may be doing too much work on its main thread.
07-18 09:45:15.452 765-1150/system_process D/ActivityManager: cleanUpApplicationRecord -- 1353
07-18 09:45:15.456 765-1842/system_process E/EGL_emulation: tid 1842: eglSurfaceAttrib(1174): error 0x3009 (EGL_BAD_MATCH)
07-18 09:45:15.456 765-1842/system_process W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xc4afa800, error=EGL_BAD_MATCH
07-18 09:45:16.337 765-780/system_process I/Choreographer: Skipped 52 frames! The application may be doing too much work on its main thread.
07-18 09:45:25.438 765-779/system_process W/ActivityManager: Activity destroy timeout for ActivityRecord{b0310c2 u0 com.example.prince.fragment_modularui2/.MainActivity t693 f}
From the stacktrace I gather that you are calling getResources() on a Context that is null. This makes sense because you are declaring your resources as a field like:
Resources res = getResources();
This gets executed before the activity is created but you can only call getResources() once the activity is created. So the solution is to declare your resources like:
private Resources res;
And in your activity onCreate method you do:
res = getResources();
This also means that you can't use the res variable until the onCreate method is executed. Generally it is better to not declare resources as a variable like that but rather declare your string array as:
String[] a;
and then in onCreate just call: a = getResources().getStringArray(R.array.desc);
One other tip I can give you is to name your variable clearer. A string array named 'a' is not very descriptive. You can call it something like descriptionArray to make it more clear.