Develop Reference

Fragment dialog issues when dismissing and in onCreate, Fragment$InstantiationException and IllegalStateException

My app is getting a couple exceptions when I rotate my phone and my progress dialog (DialogFragment) is visible. Not quite sure if I’m following the correct process for creating and dismissing a dialog fragment. If I don’t rotate my phone when the dialog is up, everything is fine.
I create and show the dialog in onCreate()
progressDialog.show(getSupportFragmentManager(),"123");
and start a background thread to load data from a server. Once the data is loaded I call the dialog’s dismiss() (using runOnUiThread(() -> {progressDialog.dismiss(); }); to stay thread safe, but note that it never gets called because I rotate and get an exception before the thread finishes). I also call the dialogs dismiss() in onStop().
I see this more often: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment myapp.ProgressDialog: could not find Fragment constructor
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: myapp, PID: 19953
java.lang.RuntimeException: Unable to start activity ComponentInfo{myapp/myapp.GameListActivity}: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment myapp.ProgressDialog: could not find Fragment constructor
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3654)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3806)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5802)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5710)
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2267)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:237)
at android.app.ActivityThread.main(ActivityThread.java:8167)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:496)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1100)
Caused by: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment myapp.ProgressDialog: could not find Fragment constructor
at androidx.fragment.app.Fragment.instantiate(Fragment.java:563)
at androidx.fragment.app.FragmentContainer.instantiate(FragmentContainer.java:57)
at androidx.fragment.app.FragmentManager$3.instantiate(FragmentManager.java:390)
at androidx.fragment.app.FragmentStateManager.<init>(FragmentStateManager.java:74)
at androidx.fragment.app.FragmentManager.restoreSaveState(FragmentManager.java:2452)
at androidx.fragment.app.FragmentController.restoreSaveState(FragmentController.java:196)
at androidx.fragment.app.FragmentActivity.onCreate(FragmentActivity.java:287)
at androidx.appcompat.app.AppCompatActivity.onCreate(AppCompatActivity.java:106)
--> at myapp.GameListActivity.onCreate(GameListActivity.java:87)
at android.app.Activity.performCreate(Activity.java:7963)
at android.app.Activity.performCreate(Activity.java:7952)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3629)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3806) 
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5802) 
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5710) 
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2267) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:237) 
at android.app.ActivityThread.main(ActivityThread.java:8167) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:496) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1100) 
Caused by: java.lang.NoSuchMethodException: myapp.ProgressDialog.<init> []
at java.lang.Class.getConstructor0(Class.java:2332)
at java.lang.Class.getConstructor(Class.java:1728)
at androidx.fragment.app.Fragment.instantiate(Fragment.java:548)
at androidx.fragment.app.FragmentContainer.instantiate(FragmentContainer.java:57) 
at androidx.fragment.app.FragmentManager$3.instantiate(FragmentManager.java:390) 
at androidx.fragment.app.FragmentStateManager.<init>(FragmentStateManager.java:74) 
at androidx.fragment.app.FragmentManager.restoreSaveState(FragmentManager.java:2452) 
at androidx.fragment.app.FragmentController.restoreSaveState(FragmentController.java:196) 
at androidx.fragment.app.FragmentActivity.onCreate(FragmentActivity.java:287) 
at androidx.appcompat.app.AppCompatActivity.onCreate(AppCompatActivity.java:106) 
at myapp.GameListActivity.onCreate(GameListActivity.java:87) 
at android.app.Activity.performCreate(Activity.java:7963) 
at android.app.Activity.performCreate(Activity.java:7952) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1307) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3629) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3806) 
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5802) 
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5710) 
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2267) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:237) 
at android.app.ActivityThread.main(ActivityThread.java:8167) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:496) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1100) 
I/Process: Sending signal. PID: 19953 SIG: 9
Disconnected from the target VM, address: 'localhost:8624', transport: 'socket'
But have also seen java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState when I’m trying to dismiss a fragment dialog (a progress dialog).
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: myapp, PID: 11658
java.lang.RuntimeException: Unable to stop activity {myapp/myapp.GameListActivity}: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.app.ActivityThread.callActivityOnStop(ActivityThread.java:5125)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5775)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5710)
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2267)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:237)
at android.app.ActivityThread.main(ActivityThread.java:8167)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:496)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1100)
Caused by: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at androidx.fragment.app.FragmentManager.checkStateLoss(FragmentManager.java:1689)
at androidx.fragment.app.FragmentManager.enqueueAction(FragmentManager.java:1729)
at androidx.fragment.app.BackStackRecord.commitInternal(BackStackRecord.java:321)
at androidx.fragment.app.BackStackRecord.commit(BackStackRecord.java:286)
at androidx.fragment.app.DialogFragment.dismissInternal(DialogFragment.java:270)
at androidx.fragment.app.DialogFragment.dismiss(DialogFragment.java:222)
--> at myapp.GameListActivity.onStop(GameListActivity.java:167)
at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1474)
at android.app.Activity.performStop(Activity.java:8195)
at android.app.ActivityThread.callActivityOnStop(ActivityThread.java:5117)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5775) 
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5710) 
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2267) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:237) 
at android.app.ActivityThread.main(ActivityThread.java:8167) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:496) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1100) 
This is my dialog fragment:
public class ProgressDialog extends DialogFragment {
public static final String TAG="lbp";
String message;
ProgressBar progressBar;
TextView progressMessage;
public ProgressDialog(String msg) {
this.message = msg;
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
View dlgView = inflater.inflate(R.layout.progress,null);
progressBar = dlgView.findViewById(R.id.progressBar);
progressMessage = dlgView.findViewById(R.id.progressMessage);
progressMessage.setText(message);
builder.setView(dlgView);
return builder.create();
}
public void setMessage(CharSequence msg) {
progressMessage.setText(msg);
}
}

Android Studio Getting Error While onClick

public void Clicking(View view) {
double one = Double.parseDouble(testtt.getText().toString());
double two = Double.parseDouble(tessss.getText().toString());
}
already;
testtt [TextView] = "0.0001974794"
tessss [TextView] = "0"
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.Testing_Appi, PID: 2988
java.lang.IllegalStateException: Could not execute method for android:onClick
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:402)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22265)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397)
at android.view.View.performClick(View.java:5610) 
at android.view.View$PerformClick.run(View.java:22265) 
at android.os.Handler.handleCallback(Handler.java:751) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:6077) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) 
Caused by: java.lang.NumberFormatException: For input string: "0.0001974794"
at java.lang.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1306)
at java.lang.Double.parseDouble(Double.java:547)
at com.example.Testing_Appi.MainActivity.testor(MainActivity.java:153)
at java.lang.reflect.Method.invoke(Native Method) 
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397) 
at android.view.View.performClick(View.java:5610) 
at android.view.View$PerformClick.run(View.java:22265) 
at android.os.Handler.handleCallback(Handler.java:751) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:6077) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) 
I couldn't spot where the error was!

Example : Find your view by id with view
EditText testttET = view.findViewById(R.id.testtt);
String text = testttET.getText().toString();
check if your text is not empty
if(!text.equals("")){
double value = Double.parseDouble(text);
}

android button causing crash [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 4 years ago.
I am trying to pass login details to another class so that it can be used to login on my MySQL db (using php) but it is crashing giving me the exception: java.lang.IllegalStateException: Could not execute method for android:onClick
stack trace: {StackTraceElement[0]#5692}
658 10752-10752/uk.ac.abertay.contactslist E/AndroidRuntime: FATAL EXCEPTION: main
Process: uk.ac.abertay.contactslist, PID: 10752
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:6294) 
at android.view.View$PerformClick.run(View.java:24770) 
at android.os.Handler.handleCallback(Handler.java:790) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6494) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void uk.ac.abertay.contactslist.Login.Logino(uk.ac.abertay.contactslist.LoginDetails)' on a null object reference
at uk.ac.abertay.contactslist.LoginActivity.Loginbutton(LoginActivity.java:40)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:6294) 
at android.view.View$PerformClick.run(View.java:24770) 
at android.os.Handler.handleCallback(Handler.java:790) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6494) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
04-26 15:39:34.761 1384-3633/? I/chatty: uid=1041(audioserver) writer identical 8 lines
this is the code for the button
private Login login;
public void Loginbutton(View v) {
/* Get entered fields data. */
String email = field_email.getText().toString();
String password = field_password.getText().toString();
login.Logino(new LoginDetails(email,password));
}
when debugging it will run this and go back to the button and after that it will give the exception and crash
public class LoginDetails {
public String email = "";
public String password = "";
LoginDetails(String e, String p) {
email = e;
password = p;
}
}
this is the code I'm trying to run with the button above
public void Logino(LoginDetails loginDetails) {
LoginTask task = new LoginTask();
task.execute(loginDetails);
}

From your StackTrace
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void uk.ac.abertay.contactslist.Login.Logino(uk.ac.abertay.contactslist.LoginDetails)
The line login.Logino the object login is null, you have to initialize it.
Obs:Please use Java naming conventions with method names starting with low case char.

Trying to perform task off the main thread. Is this source code doing that?

For a few days I've been trying to figure out this multithreading thing on Android Studio. I've only used SwingWorker in the past and after trying several ways to get my https connection to initiate off of the main thread I'm pulling my hair out. I've tried everything from using ASyncTask to just starting a thread everytime the connection gets made, but nothing seems to work. My app crashes every time. The most recent attempt is pictured below.
Edit: It's not a duplicate. I've read that thread and it doesn't do anything to help solve this problem. I'm attempting to execute this task outside of the main thread, but I don't know why my code isn't doing that already since I change to the background thread in run(); and even start a new thread just in case.
public class YelpActivity extends AppCompatActivity implements Runnable{
private yelpLoader load;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_yelp);
}
public void run(){
Thread t = new Thread();
t.start();
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_BACKGROUND);
YelpAPI test = new YelpAPI();
test.run();
}
public void yelpClick(View v){
run();
changeYelpResults(v,"test");
}
private void changeYelpResults(View v, String text){
TextView t = (TextView) findViewById(R.id.ResturauntID);
t.setText(text);
}
}
Error Log:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: tastr.tastr, PID: 3560
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: org.scribe.exceptions.OAuthConnectionException: There was a problem while creating a connection to the remote service.
at org.scribe.model.Request.send(Request.java:70)
at org.scribe.model.Request.send(Request.java:76)
at tastr.tastr.YelpAPI.sendRequestAndGetResponse(YelpAPI.java:132)
at tastr.tastr.YelpAPI.searchForBusinessesByLocation(YelpAPI.java:89)
at tastr.tastr.YelpAPI.queryAPI(YelpAPI.java:146)
at tastr.tastr.YelpAPI.run(YelpAPI.java:190)
at tastr.tastr.YelpActivity.run(YelpActivity.java:26)
at tastr.tastr.YelpActivity.yelpClick(YelpActivity.java:31)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
at java.net.InetAddress.getAllByName(InetAddress.java:215)
at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188)
at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100)
at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:357)
at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:340)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:330)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:433)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:114)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.connect(DelegatingHttpsURLConnection.java:89)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java)
at org.scribe.model.Response.<init>(Response.java:29)
at org.scribe.model.Request.doSend(Request.java:117)
at org.scribe.model.Request.send(Request.java:66)
at org.scribe.model.Request.send(Request.java:76) 
at tastr.tastr.YelpAPI.sendRequestAndGetResponse(YelpAPI.java:132) 
at tastr.tastr.YelpAPI.searchForBusinessesByLocation(YelpAPI.java:89) 
at tastr.tastr.YelpAPI.queryAPI(YelpAPI.java:146) 
at tastr.tastr.YelpAPI.run(YelpAPI.java:190) 
at tastr.tastr.YelpActivity.run(YelpActivity.java:26) 
at tastr.tastr.YelpActivity.yelpClick(YelpActivity.java:31) 
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

public class YelpActivity extends AppCompatActivity{
private yelpLoader load;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_yelp);
}
public void run(){
new Thread(new Runnable() {
#Override
public void run() {
YelpAPI test = new YelpAPI();
test.run();
}
}).start();
}
public void yelpClick(View v){
run();
changeYelpResults(v,"test");
}
private void changeYelpResults(View v, String text){
TextView t = (TextView) findViewById(R.id.ResturauntID);
t.setText(text);
}
}
Note: It's not a good practice to implement Runnable in Activity
class. Use Core Java threads like I did in the run method or Use other
Android Background mechanism like AsyncTask/IntentService.

Android Studio & Firebase... Multiple activities

I have Firebase fully installed into Android Studio, and I've tested it with a couple 1 activity applications, but on the only application with more than one activity, it's not working.
When I try to do the following in my 'Sign up' code:
private void makeStudent(String email, String password) {
Student s = new Student(email, password);
Firebase ref = new Firebase("MYAPP.firebaseio.com/");
//took out my app name
Firebase studentlocation = ref.child("Student");
studentlocation.setValue(s); //this is the line on which I get the error
//also, when I go on my firebase site, it hasn't created the Student
//directory
}
The Firebase page said:
If your Android app has multiple activities, add this code to your Application Class. Otherwise add it in your main activity.
So, I looked around, and this is what I created:
I made a MyApplication.java file, which contained:
import com.firebase.client.Firebase;
public class MyApplication extends android.app.Application {
#Override
public void onCreate() {
super.onCreate();
Firebase.setAndroidContext(this);
}
}
Then I placed the following into AndroidManifest.xml:
android:name=".MyApplication"
Yet, I still receive an error on the exact same line.
How do I fix this Firebase issue? I appreciate any help I can get, please!
ERROR RECEIVED (scroll to the right in the code box):
FATAL EXCEPTION: main
Process: professionalgrader.professionalgrader, PID: 3827
com.firebase.client.FirebaseException: Failed to parse to snapshot
at com.firebase.client.Firebase.setValueInternal(Firebase.java:347)
at com.firebase.client.Firebase.setValue(Firebase.java:238)
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94)
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16)
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalArgumentException: length=0; index=0 (through reference chain: professionalgrader.professionalgrader.Student["listofTermClasses"])
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2615)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542)
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336)
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: com.fasterxml.jackson.databind.JsonMappingException: length=0; index=0 (through reference chain: professionalgrader.professionalgrader.Student["listofTermClasses"])
at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:184)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:605)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at professionalgrader.professionalgrader.Student.getListofTermClasses(Student.java:252)
at java.lang.reflect.Method.invoke(Native Method)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.get(BeanPropertyWriter.java:679)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:534)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142) 
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118) 
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593) 
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
THE SECOND ERROR:
06-15 04:13:34.902 3089-3089/professionalgrader.professionalgrader E/AndroidRuntime: FATAL EXCEPTION: main
Process: professionalgrader.professionalgrader, PID: 3089
com.firebase.client.FirebaseException: Failed to parse to snapshot
at com.firebase.client.Firebase.setValueInternal(Firebase.java:347)
at com.firebase.client.Firebase.setValue(Firebase.java:238)
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94)
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16)
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalArgumentException: Attempt to invoke virtual method 'double professionalgrader.professionalgrader.Class.getGPA()' on a null object reference (through reference chain: professionalgrader.professionalgrader.Student["totalGPA"])
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2615)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542)
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336)
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Attempt to invoke virtual method 'double professionalgrader.professionalgrader.Class.getGPA()' on a null object reference (through reference chain: professionalgrader.professionalgrader.Student["totalGPA"])
at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:184)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:605)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'double professionalgrader.professionalgrader.Class.getGPA()' on a null object reference
at professionalgrader.professionalgrader.Student.getTotalGPA(Student.java:199)
at java.lang.reflect.Method.invoke(Native Method)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.get(BeanPropertyWriter.java:679)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:534)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142) 
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118) 
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593) 
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Possible source of error because it told me it couldn't obtain the Snapshot at the line in makeStudent(), but makeStudent() doesn't use Snapshot. Only userExists() does. Note: The variable 'exists' is defined as a static boolean in the SignUp class.
private boolean userExists() {
Firebase ref = new Firebase("MYAPPNAME.firebaseio.com");
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
for (DataSnapshot postSnapShot: snapshot.getChildren()) {
Student s = postSnapShot.getValue(Student.class);
if(s.getEmail().equals(mEmailView.getText().toString())) {
exists = true;
}
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
exists = true;
}
});
return exists;
}
SOLUTION TO MY ISSUE:
I realized that Snapshot was never used in makeStudent(), and that was where the error started. Thus, I looked in the only place it was used... userExists(), and it turned out that I was correct! The error was produced by trying to identify Student s as a nonexistent student! Thus, I actually needed a try like such:
private boolean userExists() {
Firebase ref = new Firebase("MYAPPNAME.firebaseio.com");
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
Student s;
for (DataSnapshot postSnapShot: snapshot.getChildren()) {
try {
s = postSnapShot.getValue(Student.class);
if(s.getEmail().equals(mEmailView.getText().toString())) {
System.out.println(snapshot.getValue());
exists = true;
}
} catch(Exception e) {
exists = false;
}
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
exists = true;
}
});
return exists;
}