Frustrated Noob: Unable to open stack trace file error

peakfreak · January 12th, 2012, 04:31 PM

Hi all
As you will guess I am a complete noob to Android dev by the fact that my issue is with a hellow world application.
I am working my way through a tutorial on hackaday.com (can't post the link yet).
I have written my code without any compile errors but when I run the app in my emulator all I get is and error saying "The appliacation has stopped unexpectedly"
I have scoured the tinterweb and tried a few things all to no avail. Looking through the LogCat I am getting permission errors (amongst others I'm unsure of yet). I'm hoping you guys and gals out there can assist.
I'm using Eclipse, My AVD is 2.1 and the LogCat information is as follows.
TIA for any help
Bren

01-12 22:21:23.905: D/AndroidRuntime(350): Shutting down VM
01-12 22:21:23.905: W/dalvikvm(350): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
01-12 22:21:23.925: E/AndroidRuntime(350): Uncaught handler: thread main exiting due to uncaught exception
01-12 22:21:23.935: E/AndroidRuntime(350): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.peakfreak.improvedhelloworld/com.peakfreak.improvedhelloworld.ImprovedHelloWorl dActivity}: java.lang.ClassCastException: android.widget.EditText
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.ActivityThread.performLaunchActivity(A ctivityThread.java:2496)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.ActivityThread.handleLaunchActivity(Ac tivityThread.java:2512)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.ActivityThread.access$2200(ActivityThr ead.java:119)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.ActivityThread$H.handleMessage(Activit yThread.java:1863)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.os.Handler.dispatchMessage(Handler.java:99 )
01-12 22:21:23.935: E/AndroidRuntime(350): at android.os.Looper.loop(Looper.java:123)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.ActivityThread.main(ActivityThread.jav a:4363)
01-12 22:21:23.935: E/AndroidRuntime(350): at java.lang.reflect.Method.invokeNative(Native Method)
01-12 22:21:23.935: E/AndroidRuntime(350): at java.lang.reflect.Method.invoke(Method.java:521)
01-12 22:21:23.935: E/AndroidRuntime(350): at com.android.internal.os.ZygoteInit$MethodAndArgsCa ller.run(ZygoteInit.java:860)
01-12 22:21:23.935: E/AndroidRuntime(350): at com.android.internal.os.ZygoteInit.main(ZygoteInit .java:618)
01-12 22:21:23.935: E/AndroidRuntime(350): at dalvik.system.NativeStart.main(Native Method)
01-12 22:21:23.935: E/AndroidRuntime(350): Caused by: java.lang.ClassCastException: android.widget.EditText
01-12 22:21:23.935: E/AndroidRuntime(350): at com.peakfreak.improvedhelloworld.ImprovedHelloWorl dActivity.onCreate(ImprovedHelloWorldActivity.java :24)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.Instrumentation.callActivityOnCreate(I nstrumentation.java:1047)
01-12 22:21:23.935: E/AndroidRuntime(350): at android.app.ActivityThread.performLaunchActivity(A ctivityThread.java:2459)
01-12 22:21:23.935: E/AndroidRuntime(350): ... 11 more
01-12 22:21:23.985: I/dalvikvm(350): threadid=7: reacting to signal 3
01-12 22:21:23.985: E/dalvikvm(350): Unable to open stack trace file '/data/anr/traces.txt': Permission denied

jiminaus · January 13th, 2012, 04:12 AM

Quote:

Originally Posted by peakfreak

Code:

01-12 22:21:23.925: E/AndroidRuntime(350): Uncaught handler: thread main exiting due to uncaught exception
01-12 22:21:23.935: E/AndroidRuntime(350): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.peakfreak.improvedhelloworld/com.peakfreak.improvedhelloworld.ImprovedHelloWorldActivity}: java.lang.ClassCastException: android.widget.EditText
(...)
01-12 22:21:23.935: E/AndroidRuntime(350): Caused by: java.lang.ClassCastException: android.widget.EditText
01-12 22:21:23.935: E/AndroidRuntime(350): at com.peakfreak.improvedhelloworld.ImprovedHelloWorldActivity.onCreate(ImprovedHelloWorldActivity.java:24)
(...)
01-12 22:21:23.985: I/dalvikvm(350): threadid=7: reacting to signal 3
01-12 22:21:23.985: E/dalvikvm(350): Unable to open stack trace file '/data/anr/traces.txt': Permission denied

At line 24 of ImprovedHelloWorldActivity.java, you're trying to cast an android.widget.EditText into something it can't be cast into.

Can you post ImprovedHelloWorldActivity.java between [CODE] ... [/CODE] tags? And preferably, highlight line 24 in red.

peakfreak · January 13th, 2012, 08:15 AM

Quote:

Originally Posted by jiminaus

At line 24 of ImprovedHelloWorldActivity.java, you're trying to cast an android.widget.EditText into something it can't be cast into.

Can you post ImprovedHelloWorldActivity.java between [CODE] ... [/CODE] tags? And preferably, highlight line 24 in red.

Hi jiminaus

Code below for the ImprovedHelloWorldActivity.java I have highlighted line 24 in red as it is within the Eclipse.

Code:



package
com.peakfreak.improvedhelloworld;
 
import


android.app.Activity;
import


android.content.Context;
import


android.os.Bundle;
import


android.view.View;
import


android.view.View.OnClickListener;
import


android.widget.Button;
import


android.widget.EditText;
import


android.widget.Toast;
 
　
　
public


class ImprovedHelloWorldActivity extends Activity {
 
EditText helloName;
/** Called when the activity is first created. */
@Override
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main); 
//Capture our button from layout
Button button = (Button)findViewById(R.id.


go);
//Register the onClick listener with the implementation above
button.setOnClickListener(


mAddListener);
} 
// Create an anonymous implementation of OnClickListener
private OnClickListener mAddListener = new OnClickListener()
{
publicvoid onClick(View v)
{
long id = 0;
// do something when the button is clicked
try
{
helloName = (EditText)findViewById(R.id.helloName); 
Context context = getApplicationContext();
CharSequence text = "Hello " + helloName.getText() + "!";
int duration = Toast.LENGTH_LONG; 
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
catch (Exception ex)
{
Context context = getApplicationContext();
CharSequence text = ex.toString() + "ID = " + id;
int duration = Toast.LENGTH_LONG; 
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
}
};
}

jiminaus · January 13th, 2012, 03:43 PM

findViewById(R.id.go) is not finding a Button as you're expecting but is finding an EditText instead. Check your layout. Go into XML tab at the bottom. What element has android:id="@+id/go"? Post the whole layout if you're stuck.

peakfreak · January 13th, 2012, 04:19 PM

After reading your first reply earlier jiminaus, I spotted my dopey mistake. It was as you say the naming of my layout items, I had the EditText and the Button names the wrong way round. I named them correctly but it still didn't work but I looked in R.java and saw that the references in there needed the 0 and 1 at the end of each reference changing also (see below highlighted in red). It's now working correctly and I have learned loads from what is a simple silly mistake :-)
Thanks very much for taking a look for me, a fresh pair of eyes always sees clearer.
Just as an aside, when I change anything in the layout (main.xml) is there any way to have Eclipse automatically rebuild the R.java file?

Code:

publicstaticfinalclass id {
publicstaticfinalintgo=0x7f050001;
publicstaticfinalinthelloName=0x7f050000;
}

jiminaus · January 13th, 2012, 04:26 PM

Eclipse will rebuild R.java as part of building your app. If you change a layout, build your app and R.java will change.

That's an important point. Never manually change R.java. The whole file is recreated when your app is built. Any manual changes will be lost.

Also try to treat R.java as opaque. Don't concern yourself with its values. If something's wrong with the values in R.java, the problem is always elsewhere.

(And please post plain text code. The syntax highlighting your using is making the code harder to read, not easier.)

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