android


“unfortunately, your app has stopped” [duplicate]


I am developing an application, and everytime I run it, I get the message:
Unfortunately, MyApp has stopped.
What can I do to solve this?
About this question - obviously inspired by What is a stack trace, and how can I use it to debug my application errors?, there are lots of questions stating that their application has crashed, without any further detail. This question aims to instruct novice Android programmers on how to try and fix their problems themselves, or ask the right questions.
This answer describes the process of retrieving the stack trace. Already have the stack trace? Read up on stack traces in "What is a stack trace, and how can I use it to debug my application errors?"
The Problem
Your application quit because an uncaught RuntimeException was thrown.
The most common of these is the NullPointerException.
How to solve it?
Every time an Android application crashes (or any Java application for that matter), a Stack trace is written to the console (in this case, logcat). This stack trace contains vital information for solving your problem.
Android Studio
In the bottom bar of the window, click on the Android button. Alternatively, you can press alt+6. Make sure your emulator or device is selected in the Devices panel. Next, try to find the stack trace, which is shown in red. There may be a lot of stuff logged into logcat, so you may need to scroll a bit. An easy way to find the stack trace is to clear the logcat (using the recycle bin on the right), and let the app crash again.
Eclipse
In the top right corner, click the DDMS button. If it is not there, you might need to add it first using the Open Perspective button to the left of the Java button. You will find the logcat pane at the bottom. First, make sure your device is selected in the topleft devices panel. Next, try to find the stack trace, which is shown in red. Again, there may be a lot of stuff logged into logcat, so you may need to scroll a bit. An easy way to find the stack trace here is to clear the logcat (using the clear log button on the top right), and let the app crash again. You should also click on the package name of your app, if it is not already selected. This will filter out only the log message made by your app.
I have found the stack trace, now what?
Yay! You're halfway to solving your problem.
You only need to find out what exactly made your application crash, by analyzing the stack trace.
Read up on stack traces in "What is a stack trace, and how can I use it to debug my application errors?"
I still can't solve my problem!
If you've found your Exception and the line where it occurred, and still cannot figure out how to fix it, don't hesitate to ask a question on StackOverflow.
Try to be as concise as possible: post the stack trace, and the relevant code (e.g. a few lines up to the line which threw the Exception).
You can use Google's ADB tool to get Logcat file to analyze the issue.
adb logcat > logcat.txt
open logcat.txt file and search for your application name. There should be information why it failed,The Line number ,Class name and ...
Just check the error in log cat.
You get the log cat option from in eclipse:
window->show view->others->Android->Logcat
Log cat contains error.
Other wise you can also check the error by executing an application in debug mode.
Firstly set breakpoint after that by doing:
right click on project->debug as->Android application
First you check which point your app has crashed (Unfortunately, MyApp has stopped.). For this you can use Log.e("TAG","Message");, using this line you can see you app log in logcat.
After that you find which point your app has stopped its very easy to solve at your side.
Note: This answer is using Android Studio 2.2.2
Note 2: I am considering that your device is successfully connected.
The first thing you do when your application crashes is look into the LogCat, at the bottom of Android Studio there's a toolbar with a list of menus:
Click on the "Android Monitor" (The one I underlined in the image above. ^)
Now, you'll get something like this:
Change "Verbose" to "Error" Now it will only show you logged errors. Don't worry about all these errors (if you got them) now.
Ok. Now, do what you did to crash your app. After your app crashes, go to your logcat. You should find a new crash log that has a lot of at:x.x.x: and Caused by: TrumpIsPresidentException for example. Go to that Caused by: statement in your logcat.
Next to that Caused By:, there should be the Exception that happened. In my case, it's a RuntimeException and under it there should be a line which contains a blue link such as:
If that Caused by: DOESN'T have a line with a blue text somewhere under it, then look for another Caused by: that does.
Click on that blue link. It should take you to where the problem occured. In my case, it was due to this line:
throw new RuntimeException();
So, now I know why it's crashing. It's because I'm throwing the exception myself. This was an obvious error.
However, let's say I got another error:
java.lang.NullPointerException
I checked my logcat, I clicked on the blue link it gave me, and it took me here:
mTextView.setText(myString);
So, now I want to debug. According to this StackOverflow question, a NullPointerException says that something is null.
So, let's find out what is null. There's two possibilities. Either mTextView is null, or myString is null. To find out, before the mTextView.setText(mString) line, I add these two lines:
Log.d("AppDebug","mTextView is null: " + String.valueOf(mTextView == null);
Log.d("AppDebug","myString is null: " + String.valueOf(myString== null);
Now, like we did previously (We changed Verose to Error), we want to change "Error" to "Debug". Since we're logging by debugging. Here's all the Log methods:
Log.
d means Debug
e means error
w means warning
v means verbose
i means information
wtf means "What a terrible failure". This is similar to Log.e
So, since we used Log.d, we're checking in Debug. That's why we changed it to debug.
Notice Log.d has a first parameter,in our case "AppDebug". Click on the "No Filters" drop down menu on the top-right of the logcat. Select "Edit Filter Configuration", give a name to your filter, and in "Log Tag" put "App Debug". Click "OK". Now, you should see two lines in the logcat:
yourPackageNameAndApp: mTextView is null: true
yourPackageNameAndApp: myString is null: false
So now we know that mTextView is null.
I observe my code, now I notice something.
I have private TextView mTextView declared at the top of my class. But, I'm not defining it.
Basically I forgot to do this in my onCreate():
mTextView = (TextView) findViewById(R.id.textview_id_in_xml);
So THAT'S why mTextView is null, because I forgot to tell my app what it is. So I add that line, run my app, and now the app doesn't crash.
You can use any of these tools:
adb logcat
adb logcat > logs.txt (you can use editors to open and search errors.)
eclipse logcat (If not visible in eclipse, Go to Windows->Show View->Others->Android->LogCat)
Android Debug Monitor or Android Device Monitor(type command monitor or open through UI)
Android Studio
I suggest to use Android Debug Monitor, it is good. Because eclipse hangs when too many logs are there, and through adb logcat filter and all difficult.
You have to check the Stack trace
How to do that?
on Your IDE Check the windows form LOGCAT
If you cant see the logcat windows go to this path and open it
window->show view->others->Android->Logcat
if you are using Google-Api go to this path
adb logcat > logcat.txt
Use the LogCat and try to find what is causing the app to crash.
To see Logcat if you use Android Studio then Press ALT + 6
or
if you use Eclipse then
Window -> Open Perspective -> Other - LogCat
Go to the LogCat, from the drop down menu select error. This will contain all the required information to help you debug. If that doesn't help, post the LogCat as an edit to your question and somebody will help you out.
Check your Logcat message and see your Manifest file. There should be something missing like defining the Activity,User permission`, etc.
In below showToast() method you have to pass another parameter for context or application context by doing so you can try it.
public void showToast(String error, Context applicationContext){
LayoutInflater inflater = getLayoutInflater();
View view = inflater.inflate(R.layout.custom_toast, (ViewGroup)
findViewById(R.id.toast_root));
TextView text = (TextView) findViewById(R.id.toast_error);
text.setText(error);
Toast toast = new Toast(applicationContext);
toast.setGravity(Gravity.TOP | Gravity.FILL_HORIZONTAL, 0, 0);
toast.setDuration(Toast.LENGTH_SHORT);
toast.setView(view);
toast.show();
}
Let me share a basic Logcat analysis for when you meet a Force Close (when app stops working).
DOCS
Basic tool from Android to collect/analyse logs is the logcat.
HERE is the Android's page about logcat
If you use android Studio, you can also check this LINK.
Capturing
Basically, you can MANUALLY capture logcat with following command (or just check AndroidMonitor window in AndroidStudio):
adb logcat
There's a lot of parameters you can add to command which helps you to filter and display the message that you want... This is personal... I always use the command below to get the message timestamp:
adb logcat -v time
You can redirect the output to a file and analyze it in a Text Editor.
Analyzing
If you app is Crashing, you'll get something like:
07-09 08:29:13.474 21144-21144/com.example.khan.abc D/AndroidRuntime: Shutting down VM
07-09 08:29:13.475 21144-21144/com.example.khan.abc E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.khan.abc, PID: 21144
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.FragmentActivity.onBackPressed()' on a null object reference
at com.example.khan.abc.AudioFragment$1.onClick(AudioFragment.java:125)
at android.view.View.performClick(View.java:4848)
at android.view.View$PerformClick.run(View.java:20262)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5631)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)
07-09 08:29:15.195 21144-21144/com.example.khan.abc I/Process: Sending signal. PID: 21144 SIG: 9
This part of the log shows you a lot of information:
When the issue happened: 07-09 08:29:13.475
It is important to check when the issue happened... You may find several errors in a log... you must be sure that you are checking the proper messages :)
Which app crashed: com.example.khan.abc
This way, you know which app crashed (to be sure that you are checking the logs about your message)
Which ERROR: java.lang.NullPointerException
A NULL Pointer Exception error
Detailed info about the error: Attempt to invoke virtual method 'void android.support.v4.app.FragmentActivity.onBackPressed()' on a null object reference
You tried to call method onBackPressed() from a FragmentActivity object. However, that object was null when you did it.
Stack Trace: Stack Trace shows you the method invocation order... Sometimes, the error happens in the calling method (and not in the called method).
at com.example.khan.abc.AudioFragment$1.onClick(AudioFragment.java:125)
Error happened in file com.example.khan.abc.AudioFragment.java, inside onClick() method at line: 125 (stacktrace shows the line that error happened)
It was called by:
at android.view.View.performClick(View.java:4848)
Which was called by:
at android.view.View$PerformClick.run(View.java:20262)
which was called by:
at android.os.Handler.handleCallback(Handler.java:815)
etc....
Overview
This was just an overview... Not all logs are simple etc... It is just to share the idea and provide a entry-level information to you...
I hope I could help you someway...
Regards
You can also get this error message on its own, without any stack trace or any further error message.
In this case you need to make sure your Android manifest is configured correctly (including any manifest merging happening from a library and any activity that would come from a library), and pay particular attention to the first activity displayed in your application in your manifest files.
Alternative Solution for Unfortunately App has stopped.
[![enter image description here][1]][1]
We get this message whenever our App forced closed by any exceptions that is not handled in android or in our application.
So we just need to take care of it when we are writing the code that will save a lots of time in tracking any type of exceptions in android.
Steps to track the exceptions in App :-
1.Open the Logcat and view the Exception.
If you cant see the logcat windows go to this path and open it
window->show view->others->Android->Logcat
We Use the LogCat and try to find, what is causing the app to crash.
2. Try to handle the exception which is shown in the logcat, and also check the other case's which may cause the exception .
3. Add an Uncaught Exception Handler in your Application to haldle all other exception .
I).Create a class MyExceptionHandler which implementsThread.UncaughtExceptionHandler
public class MyExceptionHandler implements
Thread.UncaughtExceptionHandler {
private final Context myContext;
private final Class<?> myActivityClass;
public MyExceptionHandler(Context context, Class<?> c) {
myContext = context;
myActivityClass = c;
}
public void uncaughtException(Thread thread, Throwable exception) {
StringWriter stackTrace = new StringWriter();
exception.printStackTrace(new PrintWriter(stackTrace));
System.err.println(stackTrace);
// You can use LogCat too
Intent intent = new Intent(myContext, myActivityClass);
myContext.startActivity(intent);
//for restarting the Activity
Process.killProcess(Process.myPid());
System.exit(0);
}
}
II).Handle exception in any class or activity or fragment.
//We need to Caught the Unwanted exception whihc is not handled by Android:
Thread.setDefaultUncaughtExceptionHandler(new MyExceptionHandler(this, SplashScreen.class));
It will restart the same Activity again if the app got crashed.
Don't forget to add your all activity name in manifest file...
and run the project again.
i hope this may help you.

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