Hey,
So im newish to android and Im lost because although my code uses AsyncTask for it's heavy lifting I am still getting a ANR error when I run my one class. So here is the relevant peices of my code:
package com.cody.color;
import android.app.Activity;
import android.os.Bundle;
public class Play extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
System.out.println("about to start threader");
new GuiThreader().execute();
System.out.println("Threader finished");
setContentView(R.layout.colorboard_small);
}
}
package com.cody.color;
import android.os.AsyncTask;
public class GuiThreader extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
System.out.println("threader moving");
GUIdriver game = new GUIdriver();
game.play();
return null;
}
}
There aren't any problems with the code above that would cause an ANR, so most likely one of the following is happening:
You are trying to modify the user interface (UI) from doInBackground
An exception is occuring in your doInBackground
If you post the LogCat output or stacktrace when you get the error then it will be easier to identify.
welcome to the world of JAVA programming :) When you encounter an error your best tool to solve it is usually going to be a stacktrace. You need to learn how to analyze a stacktrace and also to include it in your questions...
What is a stacktrace you ask? The simplistic answer is that a stacktrace is an error message (although it contains a lot more info than only that). In case of an exception it tells the programmer WHAT happened, WHERE it happened and WHEN it happened. If you want to program in JAVA you need to get yourself quite familiar with them. I recommend you read some JAVA tutorials before diving into Android development.
As for your code, without the stacktrace I cannot say more... there is no obvious error except the fact that game.play(); looks like it might contain some changes to the UI, which are not allowed in another thread than the main thread (that's why AsyncTask has onPostExecute());
Related
Since a couple of weeks, I'm seeing more and more crashes of my app with the following exception
Fatal Exception: java.lang.NoClassDefFoundError
android.os.AsyncTask
This code has run for month without any issue, and it seems now to fail on some devices (75% android 2.3.x and 25% android 4.0.3)
It fails when I create a new instance of a class which extends AsyncTask.
I create this class from the UI thread.
How can that class be not found as it's defined within the SDK ?
Yes, looks like it is a problem with one of the versions of Google play Services. See https://code.google.com/p/android/issues/detail?id=81083
A work around is to add:
try {
Class.forName("android.os.AsyncTask");
}
catch(Throwable ignore) {
// ignored
}
into your Application#onCreate()
this appears to ensure that the root classloader loads AsyncTask so that it is then available from within Play Services.
It looks like yet another Google Play Services bug...
https://groups.google.com/forum/#!topic/google-admob-ads-sdk/_x12qmjWI7M
Edit: confirmed by Google staff => https://groups.google.com/d/msg/google-admob-ads-sdk/_x12qmjWI7M/9ZQs-v0ZZTMJ
Same issue here.
I see them for 95% of the cases on android 4.0.3 devices. remaining 5% for 2.3 devices
Errors are randomly occurring from different parts of the code.
Some examples:
java.lang.NoClassDefFoundError: android/os/AsyncTask
at android.webkit.WebView.setupPackageListener(WebView.java:1305)
at android.webkit.WebView.<init>(WebView.java:1176)
at android.webkit.WebView.<init>(WebView.java:1136)
and
java.lang.NoClassDefFoundError: android/os/AsyncTask
at android.webkit.WebView.setupPackageListener(WebView.java:1354)
at android.webkit.WebView.access$10900(WebView.java:363)
at android.webkit.WebView$PrivateHandler.handleMessage(WebView.java:10411)
and
java.lang.NoClassDefFoundError: android.os.AsyncTask
at android.webkit.WebView.setupPackageListener(WebView.java:1385)
at android.webkit.WebView.<init>(WebView.java:1192)
at android.webkit.WebView.<init>(WebView.java:1150)
at android.webkit.WebView.<init>(WebView.java:1135)
at android.webkit.WebView.<init>(WebView.java:1106)
at android.webkit.WebView.<init>(WebView.java:1093)
at com.google.android.gms.ads.internal.util.g.f(SourceFile:400)
at com.google.android.gms.ads.internal.util.g.a(SourceFile:385)
it is completely unclear why these errors are happening. usually i dont see anything in the stacktrace pointing to my code.
I have the same error:
BuscaDatosJugador().execute(participante.getIconImageUrl(),String.valueOf(altoenvio), String.valueOf(contador));
My solution:
final Runnable r = new Runnable()
{
public void run()
{
try {
--- my code ---
}
};
r.run();
}
I experienced same error on android 2.3.3, but same app was stable on 4.0+. It's a Freemium and the error occurs only when in FREE mode, which runs Google Admob adverts. So the error has to be connected with this but I do no have the detail. Here is how I solved the problem:
Execute a statement that would cause the AsyncTask class to be loaded before loading the ads.
steps 1: Create a dummy AsyncTask extension class
public class DummyAsyncTask extends AsyncTask<Void, Void, Void>{
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
return null;
}
}
step 2: just in your main activity:
public class MainActivity extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new DummyAsyncTask();
.
.some code
.
load your ads here
}
}
After step 2 above, all other code section that instantiates AsyncTask extended class run normally.
I am developing on a library that is somehow getting a CalledFromWrongThread Exception crash on Samsung Galaxy S1 (api v7 - android 2.1). The code is something like this:
class MyWebViewClient extends WebViewClient {
#Override
public void shouldOverrideUrlLoading(WebView view, String url) {
someListener.addToUiView();
}
}
and of course, the method that is actually throwing the error (which implements a listener callback):
View v;
public void addToUiView(){
v.addView(new TextView(context)); //<-- this line is throwing the error on rare occasions
}
I'm skipping some code in between, but i'm not doing anything weird in other places. Also note: this crash only seems to have been happening a very very small % of the time. (not necessarily conclusive, as not everyone reports their data).
has anyone else come across this?? Is WebCore threading messing things up?
Now I haven't actually tested this but I am going to answer to the best of my knowledge. That said, my instinct is telling me that you are only seeing the error intermittently because web requests from a WebView (browser) happen with varying levels of asynchronicity and probably utilize a thread pool to accomplish this. Basically, sometimes it requests resources in parallel and sometimes it doesn't. Worse yet you might be seeing this error on only a single device because OEMs optimize OS level code (like the WebView internals) based on their preferences and opinions (especially Samsung). Either way the real problem is that you are doing something "UI related" in a place that is definitely not guaranteed to be "UI friendly"... That is, anywhere where you are getting a subsystem callback.
The solution to your problem is much more simpler than the explanation: just use your context (that I am assuming is an Activity)..
Activitys have a built in function called runOnUiThread(Runnable) that will guard the code inside the runnable from running on the wrong thread. Basically, your problem is really common and android has a built-in solution. runOnUiThread will only add overhead if required, in other words if your thread is the UI thread, it will just run the Runnable, if it isn't it uses the correct Handler (the one associated with the UI thread) to run the Runnable.
Here is what it should look like:
View v;
public void addToUiView() {
final Activity activity = (Activity) context;
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
v.addView(new TextView(activity));
}
});
}
i coded that up right inside the SO window so my apologies for any egregious errors, I hope that helps, and let me know if you need more info or of this doesn't solve your problem -ck
I have a problem with jsoup on android. I have seen the other posts and tried solutions that were suggested there ( re-adding the jars, calling android fix tool, etc.)
I have added the jsoup jar to my android project (using build path), and added the required
internet permission to my manifest.
<uses-permission android:name="android.permission.INTERNET" />
but when I am trying to run my application I am getting
Could not find method org.jsoup.Jsoup.connect, referenced from method com.example.test.MainActivity.onCreate
I have tried to use the android fix tool but it did not solve the problem.
All I have is a main activity and I am trying to call
Document doc = Jsoup.connect("http://en.wikipedia.org/").get();
attached is part of my code
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
Document doc = Jsoup.connect("http://en.wikipedia.org/").get();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
You are trying to run your connection in your main thread. Use AsyncTask and it will work.
I.E.
public class JsoupParser extends AsyncTask...
Why you have to use AsyncTask for network connections in android?
AsyncTask is an abstract helper class that enables you to use the UI thread correctly, while performing background operations in a different thread, without having to really handle threads or controllers. Since android is implemented using a single thread model, each time you launch an application, a new thread will be created.
Imagine you have a single thread model where you at a button click will parse a website using Jsoup. This would have worked fine in earler android versions, though you would have had a non-responsive screen until the network operation is done. The AsyncTask will run in the background enabling your screen to still be responsive while another thread takes care of the network communication.
Take a look in the API:
AsyncTask
NetworkOnMainThreadException
Delete all statements like:
System.out.println(something);
It worked for me, realizing this took me 2 hours.
In you normal activity
use this
public static int SDK_INT = android.os.Build.VERSION.SDK_INT;
and before fetching Document
write this inside try block
if (SDK_INT >= 10) {
ThreadPolicy tp = ThreadPolicy.LAX;
StrictMode.setThreadPolicy(tp);
}
it worked for me
I have created an application that extensively requires user inputs and interaction and even though I have made sure that I test and catch every possible case that might throw an error I want to be able to create a mechanism that traces the error in case my application crashes on the field.
I want to be able to record the entire flow right from a button click till whatever the user might be selecting or the navigation between the pages in a log file such that in case my application crashes I'm able to study the trace file later and know exactly where the error occurred.
I'm very new to this sort of programming and therefore any pointers on the above will be very helpful! Thank you in advance :]
PS: I'm not even sure whether what im referring to will be correctly called a "log trace" or not so any edit is welcome. :)
EDIT : I also want to be able to save the error report generated and send it to a particular id (similar to 'send an error report to xyz).
UPDATE :
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
try {
File myFiles = new File("/sdcard/ScanApp");
if(!myFiles.exists())
{
myFiles.mkdirs();
}
File myFile = new File("sdcard/ScanApp/log.txt");
myFile.createNewFile();
myFile.delete();
myFile.createNewFile();
String cmd = "logcat -d -v time -f "+myFile.getAbsolutePath()+ " -s ActivityManager:V";
Runtime.getRuntime().exec(cmd);
Logs.this.finish();
}
catch (Exception e)
{
flag=1;
error=e.getMessage();
}
I used this in a previous application for recording any application activity and make a textfile and save it to the SD card, but the contents weren't exactly what I was looking for. Is the solution im looking for something along these lines?
Here, check for the link for reference.
In here you create a class say ExceptionHandler that implements java.lang.Thread.UncaughtExceptionHandler..
Inside this class you will do your life saving stuff like creating stacktrace and gettin ready to upload error report etc....
Now comes the important part i.e. How to catch that exception.
Though it is very simple. Copy following line of code in your each Activity just after the call of super method in your overriden onCreate method.
Thread.setDefaultUncaughtExceptionHandler(new UncaughtExceptionHandler(this));
Your Activity may look something like this…
public class ForceClose extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Thread.setDefaultUncaughtExceptionHandler(new UncaughtExceptionHandler(this));
setContentView(R.layout.main);
}
}
Hope this helps...
You need to look up on Exception Handling. That is when your application crashes or any other app level errors occur, the code in the exception block executes. So in that place, log that error in a text-file and which solves your "log trace" issue.
Refer the link for beautiful examples.
I need to implement Sentry for my android app, I try to find an example about how I have to implement this, but I can't find it.
I saw the Sentry documentation in http://sentry.readthedocs.org/en/latest/developer/client/index.html#server_name
But I have some questions.
If my app crash, the exception will be captured?
Should I put this code line into my try/catch?
var $resultId = myClient->captureException($myException); (in android code)
If somebody has a sample in android I will be grateful.
Thank you!
I am a little late but I just recently released a Sentry client for Android. It's in its early stages so feel free to pull request any changes that you see.
https://github.com/joshdholtz/Sentry-Android
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Sentry will look for uncaught exceptions from previous runs and send them
Sentry.init(this, "YOUR-SENTRY-DSN");
}
}
Maybe try using something like BugSense? http://www.bugsense.com/
If it definitely has to be Sentry, then look at this example: https://stackoverflow.com/a/755151/349012
It shows you how to set your own uncaught exception handler so you can try and upload to Sentry.