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Error Inflating Activity from Fragment: InflateException

I have a fragment, and I want to click on a button in the fragment to open a corresponding Activity that also hosts a fragment.
I am trying to test how the Activity appears (after button click) and am receiving what appears to be an inflation error. Here is the first fragment containing the button to view the next fragment:
HomePollsFragment.Java
mLatestTestButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent latestActivity = new Intent(getActivity().getApplicationContext(), LatestActivity.class);
startActivity(latestActivity);
}
});
And then here is the code for the activity that is opened on button click:
public class LatestActivity extends AppCompatActivity implements LatestFragment.OnFragmentInteractionListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_latest);
// Check that the activity is using the layout version with
// the fragment_container FrameLayout
if (findViewById(R.id.latest_fragment_container) != null) {
// However, if we're being restored from a previous state,
// then we don't need to do anything and should return or else
// we could end up with overlapping fragments.
if (savedInstanceState != null) {
return;
}
// Create a new Fragment to be placed in the activity layout
LatestFragment latestFragment = new LatestFragment();
// In case this activity was started with special instructions from an
// Intent, pass the Intent's extras to the fragment as arguments
latestFragment.setArguments(getIntent().getExtras());
// Add the fragment to the 'fragment_container' FrameLayout
getSupportFragmentManager().beginTransaction()
.add(R.id.latest_fragment_container, latestFragment).commit();
}
}
#Override
public void onFragmentInteraction(Uri uri) {
}
}
The error I am receiving is below and appears to be related to the following line:
setContentView(R.layout.activity_latest);
Error:
06-27 22:35:47.787 4252-4252/com.sourcey.materialloginexample E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sourcey.materialloginexample/com.troychuinard.fanpolls.LatestActivity}: android.view.InflateException: Binary XML file line #6: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #6: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:713)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:280)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at com.troychuinard.fanpolls.LatestActivity.onCreate(LatestActivity.java:14)
at android.app.Activity.performCreate(Activity.java:5133)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261) 
at android.app.ActivityThread.access$600(ActivityThread.java:141) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:137) 
at android.app.ActivityThread.main(ActivityThread.java:5103) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:525) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: java.lang.NullPointerException: name == null
at java.lang.VMClassLoader.findLoadedClass(Native Method)
at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:491)
at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
at android.support.v4.app.Fragment.isSupportFragmentClass(Fragment.java:454)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2252)
at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:356)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:79)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:689)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:492) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:397) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:353) 
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:280) 
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140) 
at com.troychuinard.fanpolls.LatestActivity.onCreate(LatestActivity.java:14) 
at android.app.Activity.performCreate(Activity.java:5133) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261) 
at android.app.ActivityThread.access$600(ActivityThread.java:141) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:137) 
at android.app.ActivityThread.main(ActivityThread.java:5103) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:525) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
at dalvik.system.NativeStart.main(Native Method) 
activity_latest.xml
<?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:id="#+id/latest_fragment_container"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp" />

The error is telling you that you have no name attribute on the <fragment> element specifying its class.
NullPointerException: name == null
However, it looks like you mean to load the Fragment yourself, so you don't want a <fragment> element. Instead, you want a ViewGroup that will hold the Fragment after the dynamic FragmentTransaction. Change your <fragment> to a <FrameLayout>.

That because you have a wrong on your activity_latest.xml. You tried to add your LatestFragment to Fragment. You can add fragment into ViewGroup like FrameLayout. Change your code like here.
<?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">
<FrameLayout
android:id="#+id/latest_fragment_container"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp" />

Set background for ListView items?

So, I have this ListView, which I would like that each one of its items had a background (the same background for all of them). So far I've been trying to use this code:
listView = (ListView) findViewById(R.id.listView);
ArrayAdapter<CharSequence> lv = ArrayAdapter.createFromResource(this,
R.array.countries_array, android.R.layout.simple_list_item_1);
listView.setAdapter(lv);
for (Integer i = 0; i < listView.getCount(); ++i) {
View listItem = listView.getChildAt(i);
listItem.setBackgroundResource(R.drawable.edittext_custom);
}
It's simple, I increment i and then use it to know the position in which it is and it will set that items background, and it repeats until all items have the same background. Sound easy. Is there a better way to do this? If not, can someone please help figure it out why this simple code doesn't work? I'm pretty sure I'm missing something basic.
Exception:
05-18 15:08:45.659 10157-10157/com.example.fabiocompany.goquiz W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41917da0)
05-18 15:08:45.679 10157-10157/com.example.fabiocompany.goquiz E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.fabiocompany.goquiz, PID: 10157
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fabiocompany.goquiz/com.example.fabiocompany.goquiz.TopicosActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2328)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2386)
at android.app.ActivityThread.access$900(ActivityThread.java:169)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5476)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.fabiocompany.goquiz.TopicosActivity.onCreate(TopicosActivity.java:47)
at android.app.Activity.performCreate(Activity.java:5451)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2386)
            at android.app.ActivityThread.access$900(ActivityThread.java:169)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1277)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5476)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
            at dalvik.system.NativeStart.main(Native Method)
XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
android:background="#drawable/bggoquiz"
tools:context="com.example.fabiocompany.goquiz.TopicosActivity"
android:focusable="true"
android:focusableInTouchMode="true">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/listView"
android:layout_below="#+id/searchView"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="10dp"
android:divider="#android:color/transparent"
android:dividerHeight="20.0sp"
/>
<SearchView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/searchView"
android:background="#drawable/edittext_custom"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
</RelativeLayout>
If you need something else, please do tell, I'll try to help.

Instead of doing all this you could create a new xml file named listitem.xml with textview as below
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/tv_item"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background = "<give your desired background>"
/>
Modify your ArrayAdapter to
ArrayAdapter<String> lv = new ArrayAdapter<String>(this,
R.layout.listitem, R.id.tv_item, <your array>);
As you are applying same background to all items simply setting it ones in xml will do the work. You do not require to loop through list.

Problem is with your this method,.listView.getChildAt(i); this works only on the items which are currently visible
So this is how you need to use them.
final int numVisibleChildren = listView.getChildCount();
final int firstVisiblePosition = listView.getFirstVisiblePosition();
for (int i = firstVisiblePosition; i < firstVisiblePosition + numVisibleChildren; i++) {
View view = listView.getChildAt(i - firstVisiblePosition);
listItem.setBackgroundResource(R.drawable.edittext_custom);
}

Assuming that listView.getChildAt is returning null because the corresponding position has an invisible (or non-existent) object, then simply test for null ...
for (Integer i = 0; i < listView.getCount(); ++i) {
View listItem = listView.getChildAt(i);
if (listItem != null) {
listItem.setBackgroundResource(R.drawable.edittext_custom);
}
}

Getting java.lang.NullPointerException when I try to use maps

First of all, I'm using Android Studio and it's my first time using maps.
I created a project, with a Navigation Drawer Activity.
File> New Project > Next > Next> Switched "Navigation Drawer Activity" and clicked next > Finish.
After, I clicked in the project with the right button > new > activity > google > google maps activity.
I put google api maps key in google_maps_api.xml.
So I opened MainActivity, and type the following inside OnCreateView function:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.activity_maps, container, false);
setUpMapIfNeeded();
return rootView;
}
then I add after that the following two functions:
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
private void setUpMap() {
mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
}
Everytime I try to execute it, I get a null pointer exception. Here is the complete error message:
04-14 19:44:40.204 4390-4390/ct.ufrn.br.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: ct.ufrn.br.myapplication, PID: 4390
java.lang.RuntimeException: Unable to start activity ComponentInfo{ct.ufrn.br.myapplication/ct.ufrn.br.myapplication.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5086)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at ct.ufrn.br.myapplication.MainActivity$PlaceholderFragment.onCreateView(MainActivity.java:142)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1194)
at android.app.Activity.performStart(Activity.java:5258)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2171)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5086)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Do you know how to solve it?
obs: I tryied the same with a blank activity (in onCreate method, instead onCreateView), and it worked well.
Here is the activity_maps.xml:
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:id="#+id/map"
tools:context="ct.ufrn.br.myapplication.MapsActivity"
android:name="com.google.android.gms.maps.SupportMapFragment" />

I solved replacing
mMap = ((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
with
mMap = ((SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map)).getMap();

Android app crashes after rotating from LANDSCAPE to PORTRAIT

I'm building my first Android app and I've consulted quite some tutorials and stackoverflow posts, but I can't seem to find the proper fix for this problem.
I've been following YouTube tutorials from TheNewBoston and Derek Banas, as well as some written tutorials.
My app runs as it should when starting the app (being in Portrait mode). When I swap it to landscape, it still works fine. However when I rotate it back to portrait, the app crashes with the following error:
04-12 23:42:12.331 28004-28004/nl.avans.mbd2.android.gideon.van.david.multipanefragment E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: nl.avans.mbd2.android.gideon.van.david.multipanefragment, PID: 28004
java.lang.RuntimeException: Unable to start activity ComponentInfo{nl.avans.mbd2.android.gideon.van.david.multipanefragment/nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainActivity}: android.view.InflateException: Binary XML file line #9: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2413)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4054)
at android.app.ActivityThread.access$1000(ActivityThread.java:175)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1314)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5602)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #9: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:719)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:761)
at android.view.LayoutInflater.inflate(LayoutInflater.java:498)
at android.view.LayoutInflater.inflate(LayoutInflater.java:398)
at android.view.LayoutInflater.inflate(LayoutInflater.java:354)
at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:240)
at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
at nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainActivity.onCreate(MainActivity.java:18)
at android.app.Activity.performCreate(Activity.java:5451)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
            at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4054)
            at android.app.ActivityThread.access$1000(ActivityThread.java:175)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1314)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:146)
            at android.app.ActivityThread.main(ActivityThread.java:5602)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
            at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalStateException: Fragment nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainPanelFragment did not create a view.
at android.app.Activity.onCreateView(Activity.java:5020)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:695)
            at android.view.LayoutInflater.rInflate(LayoutInflater.java:761)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:498)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:398)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:354)
            at android.support.v7.app.ActionBarActivityDelegateBase.setContentView(ActionBarActivityDelegateBase.java:240)
            at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:102)
            at nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainActivity.onCreate(MainActivity.java:18)
            at android.app.Activity.performCreate(Activity.java:5451)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
            at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4054)
            at android.app.ActivityThread.access$1000(ActivityThread.java:175)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1314)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:146)
            at android.app.ActivityThread.main(ActivityThread.java:5602)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
            at dalvik.system.NativeStart.main(Native Method)
The actual error being:
java.lang.RuntimeException: Unable to start activity ComponentInfo{nl.avans.mbd2.android.gideon.van.david.multipanefragment/nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainActivity}: android.view.InflateException: Binary XML file line #9: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #9: Error inflating class fragment
Caused by: java.lang.IllegalStateException: Fragment nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainPanelFragment did not create a view.
My MainActivity looks like this:
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int screenOrientation = getResources().getConfiguration().orientation;
if (screenOrientation == Configuration.ORIENTATION_PORTRAIT) {
hideSidePanel();
}
}
private void hideSidePanel() {
View detailPane = findViewById(R.id.detail_panel);
if(detailPane.getVisibility() == View.VISIBLE) {
detailPane.setVisibility(View.GONE);
}
}
}
MainPanelFragment:
public class MainPanelFragment extends ListFragment {
boolean orientation;
int currentListViewItem;
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
ArrayAdapter<String> connectArrayToListView = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_activated_1, API.dummyData);
setListAdapter(connectArrayToListView);
orientation = getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE;
if (savedInstanceState != null) {
currentListViewItem = savedInstanceState.getInt("curChoice", 0);
}
if (orientation) {
getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
showDetails(currentListViewItem);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
return inflater.inflate(R.layout.fragment_main_panel, container, false);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("curChoice", currentListViewItem);
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
showDetails(position);
// super.onListItemClick(l, v, position, id);
}
void showDetails(int kaart) {
currentListViewItem = kaart;
if (orientation) {
getListView().setItemChecked(kaart, true);
DetailPanelFragment details = (DetailPanelFragment) getFragmentManager().findFragmentById(R.id.detail_panel);
if (details == null || details.getShowIndex() == -1) {
details = DetailPanelFragment.newInstance(kaart);
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.main_panel, details);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
}
} else {
Intent intent = new Intent();
intent.setClass(getActivity(), DetailsActivity.class);
intent.putExtra("index", kaart);
startActivity(intent);
}
}
}
activity_main.xml:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:animateLayoutChanges="true"
tools:context=".MainActivity">
<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="2"
android:id="#+id/main_panel"
android:layout_alignParentRight="true"
class="nl.avans.mbd2.android.gideon.van.david.multipanefragment.MainPanelFragment"/>
<fragment
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="#+id/detail_panel"
android:layout_alignParentLeft="true"
class="nl.avans.mbd2.android.gideon.van.david.multipanefragment.DetailPanelFragment"/>
</LinearLayout>
fragment_detail_panel.xml:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/holo_blue_bright"
android:layout_gravity="top|center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Detail panel"
android:textColor="#android:color/white"
android:textStyle="bold"
android:id="#+id/kaartenListViewDetail"
/>
</LinearLayout>
fragment_main_panel.xml:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/holo_red_dark"
android:layout_gravity="top|center"
android:orientation="vertical">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#android:id/list">
</ListView>
</LinearLayout>
I also have a folder in /res named layout-land. It contains an activity_main.xml file which is exactly identical to the one posted above.
I've seen similiar questions like this one but it seems that this situation is not (enough) the same to find a valid answer.

App crash when trying to access mapfragment

i am creating a project for school with a mapfragment and a button, but when i try to access my map, it crashes completely
this is my code:
package com.helloandroid.mapview;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import com.google.android.gms.maps.*;
import com.google.android.gms.maps.model.*;
public class MainActivity extends ActionBarActivity {
GoogleMap myMap;
Button btnShow;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
btnShow = (Button) findViewById(R.id.btnShow);
this is the line where it crashes:
SupportMapFragment mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
myMap = mapFrag.getMap();
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
}
this is my logcat result:
01-09 20:19:57.475 28744-28744/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.helloandroid.mapview/com.helloandroid.mapview.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2306)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358)
at android.app.ActivityThread.access$600(ActivityThread.java:156)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:5297)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.helloandroid.mapview.MainActivity.onCreate(MainActivity.java:34)
at android.app.Activity.performCreate(Activity.java:5122)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1081)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358)
            at android.app.ActivityThread.access$600(ActivityThread.java:156)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:153)
            at android.app.ActivityThread.main(ActivityThread.java:5297)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
            at dalvik.system.NativeStart.main(Native Method)
this is the mapfragment
<fragment
android:id="#+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_below="#+id/btnShow" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Show"
android:id="#+id/btnShow"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
does anybody know how i can fix this?
thanks in advance

Correct setup
First off you need to check if the device has the correct Google Play services, if it hasn't got it properly set up, you will not be able to use the map at all.
if (GooglePlayServicesUtil.isGooglePlayServicesAvailable(this) != ConnectionResult.SUCCESS) {
// Handle the case here
}
Second, you don't get any guarantee that the map will be ready, therefore you will need to try to set up the map multiple times, e.g. call this method both from OnCreate(..) and onResume(..).
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
// here you can setup the map the way you want
}
}
}
Your error
You are getting a NullPointerException when you access the SupportMapFragment? Check the following:
Are you sure that you have included the android-support-v4.jar support library?
Are you sure that R.id.map exists?
Do you have the google play services lib correctly included in your project?
If you still run into problems you should include the xml for the map fragment.
EDIT
Your XML setup should have this
class="com.google.android.gms.maps.SupportMapFragment", i.e. remove the android:name attribute from fragment and add the class.

In your xml file you wrote:
android:name="com.google.android.gms.maps.MapFragment"
and in your java code you can access it by
SupportMapFragment mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
So just you have to need to change from
android:name="com.google.android.gms.maps.MapFragment"
to
android:name="com.google.android.gms.maps.SupportMapFragment"
in your xml file.

Simply Replace
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android
android:id="#+id/map"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="com.google.android.gms.maps.SupportMapFragment" />
with this
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/map"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
and access Mapview like this
GoogleMap googleMap;
..
..
googleMap = ((MapFragment) getActivity().getFragmentManager()
.findFragmentById(R.id.map)).getMap();
googleMap.getUiSettings().setZoomControlsEnabled(true);
Hope it will help somebody.