I know this answer is probably simple but i cannot figure it out. I am modifying example code for a project and keep getting a ClassCastException when i try to launch the app. Says that ListActivityFragment cannot be cast to android.app.Activity. What im not understanding(which is probably the simple part) is why its trying to cast it onto an activity when my main is a fragmentactivity. I know the code is rough, still trying to finish it up but cant get past this.
FragmentActivity
public class MainActivity extends FragmentActivity {
private boolean isLargeScreen = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (findViewById(R.id.normal_screen_layout) != null) {
isLargeScreen = false;
ListActivityFragment listActivityFragment = new ListActivityFragment();
listActivityFragment.setArguments(getIntent().getExtras());
getSupportFragmentManager().beginTransaction()
.add(R.id.normal_screen_layout, listActivityFragment)
.commit();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.addItem:
ListActivityFragment newFragment = new ListActivityFragment();
FragmentTransaction transaction = getSupportFragmentManager()
.beginTransaction();
transaction.replace(R.id.normal_screen_layout, newFragment);
transaction.addToBackStack(null);
transaction.commit();
break;
default:
return super.onOptionsItemSelected(item);
}
return true;
}
}
}
ListActivity
public class ListActivityFragment extends ListFragment implements
OnClickListener {
private ArrayList<String> items = new ArrayList<String>();
private ListView listView;
private View outerView;
private Button deleteButton;
private ListActivityListener listener;
public interface ListActivityListener {
public void meetingAdded();
}
public ListActivityFragment() {
}
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
listener = (ListActivityListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnHeadlineSelectedListener");
}
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
outerView = inflater.inflate(R.layout.list_of_meetings, container,
false);
listView = (ListView) outerView.findViewById(R.id.listView1);
deleteButton = (Button) outerView.findViewById(R.id.deleteButton);
createList();
return outerView;
}
public void createList() {
items.clear();
Iterator<Items> iterator = ItemCollection.Instance().iterator();
while (iterator.hasNext()) {
items.add(iterator.next().toString());
}
listView.setAdapter(new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, items));
}
#Override
public void onClick(DialogInterface arg0, int arg1) {
ListView listView = getListView();
for (int index = 0; index < listView.getChildCount(); index++) {
View viewGroup = listView.getChildAt(index);
CheckBox checkBox = (CheckBox) viewGroup
.findViewById(R.id.itemSelectCheckBox);
if (checkBox.isChecked()) {
TextView textView = (TextView) viewGroup
.findViewById(R.id.productTextView);
int key = (Integer) textView.getTag();
ItemCollection.Instance().delete(key);
}
}
createList();
}
#Override
public void onStart() {
super.onStart();
}
public void onListItemClick(ListView l, View v, int position, long id) {
getListView().setItemChecked(position, true);
}
}
And heres the Logcat
07-15 01:59:50.710: E/AndroidRuntime(878): FATAL EXCEPTION: main
07-15 01:59:50.710: E/AndroidRuntime(878): Process: com.example.assignment5, PID: 878
07-15 01:59:50.710: E/AndroidRuntime(878): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.assignment5/com.example.assignment5.ListActivityFragment}: java.lang.ClassCastException: com.example.assignment5.ListActivityFragment cannot be cast to android.app.Activity
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.ActivityThread.access$800(ActivityThread.java:135)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.os.Handler.dispatchMessage(Handler.java:102)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.os.Looper.loop(Looper.java:136)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.ActivityThread.main(ActivityThread.java:5017)
07-15 01:59:50.710: E/AndroidRuntime(878): at java.lang.reflect.Method.invokeNative(Native Method)
07-15 01:59:50.710: E/AndroidRuntime(878): at java.lang.reflect.Method.invoke(Method.java:515)
07-15 01:59:50.710: E/AndroidRuntime(878): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-15 01:59:50.710: E/AndroidRuntime(878): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-15 01:59:50.710: E/AndroidRuntime(878): at dalvik.system.NativeStart.main(Native Method)
07-15 01:59:50.710: E/AndroidRuntime(878): Caused by: java.lang.ClassCastException: com.example.assignment5.ListActivityFragment cannot be cast to android.app.Activity
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
07-15 01:59:50.710: E/AndroidRuntime(878): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
07-15 01:59:50.710: E/AndroidRuntime(878): ... 11 more
07-15 01:59:51.160: E/NetdConnector(383): NDC Command {65 bandwidth setiquota eth0 9223372036854775807} took too long (1117ms)
Caused by: java.lang.ClassCastException:
com.example.assignment5.ListActivityFragment cannot be cast to
android.app.Activity 07-15 01:59:50.710: E/AndroidRuntime(878):
As the error says -
ListActivityFragment is not an activity. So you are trying to access it just like an activity.
Make sure you haven't declared ListActivityFragment in the manifest. In your manifest if you made an entry for the fragment then that's wrong.
Also make sure that you haven't used startActivity for the fragment. Because this is done for activity class and not for fragment class.
Related
I have this problem that whenever i click on the listView OnItemClick method it always crashes when it is trying to reach another intent down below i leave some code.
public class SelectFichas extends AppCompatActivity {
TextView tv;
ListView lv;
RecyclerView.LayoutManager mLayoutManager;
ImageButton btn1;
ArrayList<Ficha> slFichas;
List<Ficha> ftchArray;
DBHelper db;
MyAdapter aAdapt = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_select_ficha);
btn1 = (ImageButton) (findViewById(R.id.rg));
lv = (ListView) (findViewById(R.id.lv1));
db = new DBHelper(this);
try {
//Verificamos que la base de datos no este vacia
if (!db.isEmpty()) {
ftchArray = db.getAllFichas();
slFichas = new ArrayList<Ficha>();
for (Ficha fi : ftchArray) {
slFichas.add(fi);
}
// mAdapter = new MyAdapter(ftchArray,getApplication());
aAdapt = new MyAdapter(SelectFichas.this,0,slFichas);
View header = getLayoutInflater().inflate(R.layout.list_header, null);
lv.addHeaderView(header);
lv.setAdapter(aAdapt);
lv.setItemsCanFocus(false);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick( AdapterView<?> parent, View view, int position, long id) {
Ficha fi = (Ficha) aAdapt.getItem(position-1);
String sel = fi.getPreg();
String[] opc = {"Actualizar", "Borrar", "Adivinar", "Atras"};
Toast.makeText(getApplicationContext(), "Usted selecciono " +sel, Toast.LENGTH_SHORT).show();
final Intent intent = new Intent(SelectFichas.this,UpdFicha.class);
Handler h = new Handler();
h.postDelayed(new Runnable() {
#Override
public void run() {
if (intent.resolveActivity(getPackageManager()) != null){
startActivity(intent);
}
}
}, 2000);
I also used a custom ArrayAdapter for my ListView is that influencing, in case i will leave some code about the adapter below.
public class MyAdapter extends ArrayAdapter<Ficha> {
private Context context;
private ArrayList<Ficha> ficha;
public MyAdapter(Context context, int resource, ArrayList<Ficha> objects) {
super(context, resource, objects);
this.context = context;
this.ficha = objects;
}
#Override
public View getView(int position, View convertView, ViewGroup parent){
Ficha fi = ficha.get(position);
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.list_items, parent,false);
RelativeLayout rv = (RelativeLayout)(view.findViewById(R.id.relativeLayout));
TextView id = (TextView)view.findViewById(R.id.id_view);
TextView preg = (TextView)view.findViewById(R.id.preg_view);
TextView ans = (TextView) view.findViewById(R.id.answer_view);
id.setText(String.valueOf(fi.getId()));
preg.setText(fi.getPreg());
ans.setText(fi.getRes());
return view;
}
}
Here is my Logcat EDITED
2-05 11:52:06.886 5997-5997/com.giamp.fichas W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x9ccbcb20)
12-05 11:52:06.886 5997-5997/com.giamp.fichas E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.giamp.fichas, PID: 5997
java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView
at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:386)
at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:193)
at android.widget.Spinner.onMeasure(Spinner.java:482)
at android.support.v7.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:416)
at android.view.View.measure(View.java:16497)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:389)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
at android.view.View.measure(View.java:16497)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1916)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1113)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1295)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:544)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.TextView
at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:379)
at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:193)
at android.widget.Spinner.onMeasure(Spinner.java:482)
at android.support.v7.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:416)
at android.view.View.measure(View.java:16497)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:389)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:16497)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
at android.view.View.measure(View.java:16497)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1916)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1113)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1295)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:544)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
AdapterView<?> parent is not an Adapter, but it is a ViewGroup.
change
ArrayAdapter<Ficha> aAdapt = new MyAdapter(SelectFichas.this, 0, slFichas);
to
final MyAdapter aAdapt = new MyAdapter(SelectFichas.this, 0, slFichas);
and
Ficha fi = (Ficha) parent.getItemAtPosition(position);
to
Ficha fi = (Ficha) aAdapt.getItem(position);
When I call .notifyDataSetChanged() in my constructor after I set my ArrayList my app still crashes, the same as when I call it before I call .setAdapter, it's been bothering me for hours, would love any kind of help, thanks!
public class CustomSwipeAdapter extends PagerAdapter {
private ArrayList<String> image_resources = new ArrayList<>();
private Context mContext;
private LayoutInflater mLayoutInflater;
private ImageLoader mImageLoader;
public CustomSwipeAdapter(Context context, ArrayList<String> images){
this.mContext = context;
this.image_resources = images;
}
#Override
public int getCount() {
return image_resources.size();
}
#Override
public boolean isViewFromObject(View view, Object object) {
return (view == (LinearLayout)object);
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
mLayoutInflater = (LayoutInflater) mContext.getSystemService(mContext.LAYOUT_INFLATER_SERVICE);
View item_view = mLayoutInflater.inflate(R.layout.swipe_layout, container, false);
final ImageView imageView = (ImageView) item_view.findViewById(R.id.imageView);
if (image_resources.get(position) != null || !image_resources.get(position).isEmpty()) {
mImageLoader.get(image_resources.get(position), new ImageLoader.ImageListener() {
#Override
public void onResponse(ImageLoader.ImageContainer response, boolean isImmediate) {
imageView.setImageBitmap(response.getBitmap());
}
#Override
public void onErrorResponse(VolleyError error) {
imageView.setBackgroundColor(Color.CYAN);
}
});
}
container.addView(item_view);
return item_view;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((LinearLayout) object);
super.destroyItem(container, position, object);
}
}
Where I set my Adapter (in my Activity's onCreate()), it's most basic activity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_page);
mViewPager = (ViewPager) findViewById(R.id.view_pager);
mVolleySingleton = VolleySingleton.getInstance();
mRequestQueue = mVolleySingleton.getRequestQueue();
sendAPIRequest();
//after you get the images
mCustomSwipeAdapter = new CustomSwipeAdapter(this, images);
mViewPager.setAdapter(mCustomSwipeAdapter);
}
Stack Trace:
java.lang.IllegalStateException: The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 0, found: 4 Pager id: sobmad.com.gamingreminder:id/view_pager Pager class: class android.support.v4.view.ViewPager Problematic adapter: class sobmad.com.gamingreminder.GamePage.CustomSwipeAdapter
at android.support.v4.view.ViewPager.populate(ViewPager.java:967)
at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
at android.view.View.measure(View.java:15848)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15848)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
at android.view.View.measure(View.java:15848)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
at android.view.Choreographer.doFrame(Choreographer.java:532)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
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)
mCustomSwipeAdapter = new CustomSwipeAdapter(this, images);
mViewPager.setAdapter(mCustomSwipeAdapter);
mCustomSwipeAdapter.notifyDataSetChange() //Add this line in your activity
I'm new to android, and I'm pretty bad at it. So bear with me and please be very clear and basic with your answers.
I'm trying to make a navigation spinner in android. I made it using the tutorial but I can't figure out how to modify the pages that they direct the user to. For now I'm trying to get them all to lead to the same page that just has a basic "Hello." The app keeps crashing though.
public class MainActivity extends ActionBarActivity implements
ActionBar.OnNavigationListener {
/**
* The serialization (saved instance state) Bundle key representing the
* current dropdown position.
*/
private static final String STATE_SELECTED_NAVIGATION_ITEM = "selected_navigation_item";
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar to show a dropdown list.
final ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
// Set up the dropdown list navigation in the action bar.
actionBar.setListNavigationCallbacks(
// Specify a SpinnerAdapter to populate the dropdown list.
new ArrayAdapter<String>(actionBar.getThemedContext(),
android.R.layout.simple_list_item_1,
android.R.id.text1, new String[] {
getString(R.string.title_section1),
getString(R.string.title_section2),
getString(R.string.title_section3), }), this);
}
public void onRestoreInstanceState(Bundle savedInstanceState) {
// Restore the previously serialized current dropdown position.
if (savedInstanceState.containsKey(STATE_SELECTED_NAVIGATION_ITEM)) {
getSupportActionBar().setSelectedNavigationItem(
savedInstanceState.getInt(STATE_SELECTED_NAVIGATION_ITEM));
}
}
public void onSaveInstanceState(Bundle outState) {
// Serialize the current dropdown position.
outState.putInt(STATE_SELECTED_NAVIGATION_ITEM, getSupportActionBar()
.getSelectedNavigationIndex());
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public boolean onNavigationItemSelected(int position, long id) {
// When the given dropdown item is selected, show its contents in the
// container view.
Intent intent = new Intent (this, Fibonacci.class);
startActivity(intent);
return true;
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
TextView textView = (TextView) rootView
.findViewById(R.id.section_label);
textView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
}
And:
public class Fibonacci extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Get the message from the intent
Intent intent = getIntent();
String message = "Hello";
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
TextView textView = (TextView) rootView
.findViewById(R.id.section_label);
textView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static int fibonacciNum (int position) {
int num = 1;
if (position <= 2) {
return 1;
}
else {
num = fibonacciNum(position-1) + fibonacciNum(position-2);
return num;
}
}
}
Logcat:
07-15 10:08:13.850: E/AndroidRuntime(921): FATAL EXCEPTION: main
07-15 10:08:13.850: E/AndroidRuntime(921): Process: com.zarwanhashem.sequences, PID: 921
07-15 10:08:13.850: E/AndroidRuntime(921): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.zarwanhashem.sequences/com.zarwanhashem.sequences.Fibonacci}; have you declared this activity in your AndroidManifest.xml?
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1628)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.Instrumentation.execStartActivity(Instrumentation.java:1424)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.Activity.startActivityForResult(Activity.java:3424)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.Activity.startActivityForResult(Activity.java:3385)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:839)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.Activity.startActivity(Activity.java:3627)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.Activity.startActivity(Activity.java:3595)
07-15 10:08:13.850: E/AndroidRuntime(921): at com.zarwanhashem.sequences.MainActivity.onNavigationItemSelected(MainActivity.java:91)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.support.v7.app.ActionBarImplICS$OnNavigationListenerWrapper.onNavigationItemSelected(ActionBarImplICS.java:355)
07-15 10:08:13.850: E/AndroidRuntime(921): at com.android.internal.widget.ActionBarView$1.onItemSelected(ActionBarView.java:145)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.widget.AdapterView.fireOnSelected(AdapterView.java:893)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.widget.AdapterView.access$200(AdapterView.java:48)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:861)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.os.Handler.handleCallback(Handler.java:733)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.os.Handler.dispatchMessage(Handler.java:95)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.os.Looper.loop(Looper.java:136)
07-15 10:08:13.850: E/AndroidRuntime(921): at android.app.ActivityThread.main(ActivityThread.java:5017)
07-15 10:08:13.850: E/AndroidRuntime(921): at java.lang.reflect.Method.invokeNative(Native Method)
07-15 10:08:13.850: E/AndroidRuntime(921): at java.lang.reflect.Method.invoke(Method.java:515)
07-15 10:08:13.850: E/AndroidRuntime(921): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-15 10:08:13.850: E/AndroidRuntime(921): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-15 10:08:13.850: E/AndroidRuntime(921): at dalvik.system.NativeStart.main(Native Method)
Manifest:
<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.zarwanhashem.sequences.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>
</application>
</manifest>
android.content.ActivityNotFoundException: Unable to find explicit
activity class
{com.zarwanhashem.sequences/com.zarwanhashem.sequences.Fibonacci};
have you declared this activity in your AndroidManifest.xml?
Every activity that you intend to call in your application must be declared in the AndroidManifest file. The minimum necessary would be:
<activity android:name=".Fibonacci" />
I'm trying to work on Google Analytics for Androi. I get the message, and I'm following the advanced configuration of Android Analytics in Google Android SDK.
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.example.secondapp/com.example.secondapp.MainActivity}:
java.lang.NullPointerException
And I get this error:
01-02 15:39:38.410: D/AndroidRuntime(1338): Shutting down VM
01-02 15:39:38.410: W/dalvikvm(1338): threadid=1: thread exiting with uncaught exception (group=0xb1ab7ba8)
01-02 15:39:38.420: E/AndroidRuntime(1338): FATAL EXCEPTION: main
01-02 15:39:38.420: E/AndroidRuntime(1338): Process: com.example.secondapp, PID: 1338
01-02 15:39:38.420: E/AndroidRuntime(1338): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.secondapp/com.example.secondapp.MainActivity}: java.lang.NullPointerException
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.ActivityThread.access$800(ActivityThread.java:135)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.os.Handler.dispatchMessage(Handler.java:102)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.os.Looper.loop(Looper.java:136)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.ActivityThread.main(ActivityThread.java:5017)
01-02 15:39:38.420: E/AndroidRuntime(1338): at java.lang.reflect.Method.invokeNative(Native Method)
01-02 15:39:38.420: E/AndroidRuntime(1338): at java.lang.reflect.Method.invoke(Method.java:515)
01-02 15:39:38.420: E/AndroidRuntime(1338): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
01-02 15:39:38.420: E/AndroidRuntime(1338): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
01-02 15:39:38.420: E/AndroidRuntime(1338): at dalvik.system.NativeStart.main(Native Method)
01-02 15:39:38.420: E/AndroidRuntime(1338): Caused by: java.lang.NullPointerException
01-02 15:39:38.420: E/AndroidRuntime(1338): at com.example.secondapp.MainActivity.onCreate(MainActivity.java:24)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.Activity.performCreate(Activity.java:5231)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
01-02 15:39:38.420: E/AndroidRuntime(1338): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
01-02 15:39:38.420: E/AndroidRuntime(1338): ... 11 more
Here is my code for SecondAppApplication, which has similarities to the android docs:
public class SecondAppApplication extends Application {
private static GoogleAnalytics mGa;
private static Tracker mTracker;
private static final String GA_PROPERTY_ID = "UA-XXXXXXXX-1";
private static final int GA_DISPATCH_PERIOD = 30;
private static final boolean GA_IS_DRY_RUN = false;
private static final LogLevel GA_LOG_VERBOSITY = LogLevel.INFO;
private static final String TRACKING_PREF_KEY = "trackingPreferences";
#SuppressWarnings("deprecation")
private void initializeGa() {
mGa = GoogleAnalytics.getInstance(this);
mTracker = mGa.getTracker(GA_PROPERTY_ID);
GAServiceManager.getInstance().setLocalDispatchPeriod(GA_DISPATCH_PERIOD);
mGa.setDryRun(GA_IS_DRY_RUN);
mGa.getLogger().setLogLevel(GA_LOG_VERBOSITY);
SharedPreferences userPrefs = PreferenceManager.getDefaultSharedPreferences(this);
userPrefs.registerOnSharedPreferenceChangeListener(new SharedPreferences.OnSharedPreferenceChangeListener() {
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
if (key.equals(TRACKING_PREF_KEY)) {
GoogleAnalytics.getInstance(getApplicationContext()).setAppOptOut(sharedPreferences.getBoolean(key, false));
}
}
});
}
#Override
public void onCreate() {
super.onCreate();
initializeGa();
}
public static Tracker getGaTracker() {
return mTracker;
}
public static GoogleAnalytics getGaInstance() {
return mGa;
}
}
Here is my MainActivity class:
public class MainActivity extends Activity {
public static final String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
private static final String SCREEN_LABEL = "Main Screen";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SecondAppApplication.getGaTracker().set(Fields.SCREEN_NAME,SCREEN_LABEL);
setContentView(R.layout.main);
}
#Override
public void onStart() {
super.onStart();
SecondAppApplication.getGaTracker().send(MapBuilder.createAppView().build());
}
#Override
public void onStop() {
super.onStop();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()) {
case R.id.action_search:
openSearch();
return true;
case R.id.action_settings:
openSettings();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void openSearch() {
}
public void openSettings() {
}
public void sendMessage(View view) {
Intent intent = new Intent(this,DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
Why does java.lang.NullPointerException exists, and/or how would I solve this?
Do I need to declare initializeGa() again inside MainActivity or AndroidManifest.xml?
It looks to me like:
SecondAppApplication.getGaTracker().set(Fields.SCREEN_NAME,SCREEN_LABEL);
Is probably calling the set method on a null object, because your accessing statically without initializing it first. This almost looks like you were trying to do a singleton or something...
I would change your code to:
public static Tracker getGaTracker() {
if(mTracker ==null) {
initialize();
}
return mTracker;
}
The problem of course being that since you're doing this statically you wont have a context to pass.... I think you may need to reorganize the project a bit.
Check out this:
Android: Persist object across activities
I found out that the AndroidManifest.xml application should contain the correct android.name.
In this case, android.name="com.example.secondapplication.SecondAppApplication"
I have the following Fragment. It works completely fine, until I rotate my device. It then crashes with errors about the RadarSelectionFragment failing to Instantiate. The code for the FragmentPagerAdapter and the Fragment in question are below:
#SuppressLint("DefaultLocale")
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter() {
// Do some stuff
}
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
if (position == 0) {
Fragment fragment = new RadarSelectionFragment();
Bundle args = new Bundle();
args.putInt(RadarSelectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
} else if (position == 1) {
Fragment fragment = new WeatherMapDisplayFragment();
Bundle args = new Bundle();
args.putInt(WeatherMapDisplayFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
} else {
Fragment tf = new RadarSelectionFragment();
return tf;
}
}
#Override
public int getCount() {
return 2;
}
#SuppressLint("DefaultLocale")
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase();
case 1:
return getString(R.string.title_section2).toUpperCase();
}
return null;
}
}
public static class RadarSelectionFragment extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public RadarSelectionFragment() {}
#Override
public final View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (getArguments().getInt(ARG_SECTION_NUMBER) == 1) {
return inflater.inflate(R.layout.radars, container, false);
} else {
return container;
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setRetainInstance(true);
...
}
public void onNothingSelected(AdapterView<?> parent) {
// Another interface callback
}
});
}
}
public class WeatherMapDisplayFragment extends Fragment {
public static final String ARG_SECTION_NUMBER = "section_number";
public WeatherMapDisplayFragment() {
}
#Override
public final View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (getArguments().getInt(ARG_SECTION_NUMBER) == 2) {
return inflater.inflate(R.layout.display, container, false);
} else {
return container;
}
}
}
I have tried Googling the problem, but all I keep turning up are various solutions pertaining to ensuring that the Fragment Class is static (Which I've done).
I am relatively new to Android programming, so if you answer, could you please either post an example and/or link to other examples if you have the time.
Thanks in advance!
EDIT 1: Stacktrace
01-21 13:46:31.907: E/AndroidRuntime(1101): FATAL EXCEPTION: main
01-21 13:46:31.907: E/AndroidRuntime(1101): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.radarau/com.example.radarau.MainActivity}: android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment com.example.radarau.MainActivity$WeatherMapDisplayFragment: make sure class name exists, is public, and has an empty constructor that is public
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3692)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread.access$700(ActivityThread.java:141)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1240)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.os.Handler.dispatchMessage(Handler.java:99)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.os.Looper.loop(Looper.java:137)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread.main(ActivityThread.java:5039)
01-21 13:46:31.907: E/AndroidRuntime(1101): at java.lang.reflect.Method.invokeNative(Native Method)
01-21 13:46:31.907: E/AndroidRuntime(1101): at java.lang.reflect.Method.invoke(Method.java:511)
01-21 13:46:31.907: E/AndroidRuntime(1101): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-21 13:46:31.907: E/AndroidRuntime(1101): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-21 13:46:31.907: E/AndroidRuntime(1101): at dalvik.system.NativeStart.main(Native Method)
01-21 13:46:31.907: E/AndroidRuntime(1101): Caused by: android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment com.example.radarau.MainActivity$WeatherMapDisplayFragment: make sure class name exists, is public, and has an empty constructor that is public
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.support.v4.app.Fragment.instantiate(Fragment.java:405)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.support.v4.app.FragmentState.instantiate(Fragment.java:97)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.support.v4.app.FragmentManagerImpl.restoreAllState(FragmentManager.java:1767)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:208)
01-21 13:46:31.907: E/AndroidRuntime(1101): at com.example.radarau.MainActivity.onCreate(MainActivity.java:35)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.Activity.performCreate(Activity.java:5104)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-21 13:46:31.907: E/AndroidRuntime(1101): ... 12 more
01-21 13:46:31.907: E/AndroidRuntime(1101): Caused by: java.lang.InstantiationException: can't instantiate class com.example.radarau.MainActivity$WeatherMapDisplayFragment; no empty constructor
01-21 13:46:31.907: E/AndroidRuntime(1101): at java.lang.Class.newInstanceImpl(Native Method)
01-21 13:46:31.907: E/AndroidRuntime(1101): at java.lang.Class.newInstance(Class.java:1319)
01-21 13:46:31.907: E/AndroidRuntime(1101): at android.support.v4.app.Fragment.instantiate(Fragment.java:394)
01-21 13:46:31.907: E/AndroidRuntime(1101): ... 19 more
Your logcat says
Caused by: android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment com.example.radarau.MainActivity$WeatherMapDisplayFragment: make sure class name exists, is public, and has an empty constructor that is public
You should provide a public Default constructor for that
public WeatherMapDisplayFragment() {
// Do some stuff
}
If that class is nested, make that class to static class and provide a public default constructor or move that fragment into a new java file.