Error: "R cannot be resolved"

[Pramod P Deore]

Hello everybody,
I am trying to run my first program in android but I got error.

I havae following code in my .java file

  

package com.micro;

import java.util.ArrayList;
import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;


public class ToDoList1 extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle icicle)
    {
    	setContentView(R.layout.main);                                                      //error
    	ListView myListView = (ListView)findViewById(R.id.myListView);        //error     
    	final EditText myEditText = (EditText)findViewById(R.id.myEditText); //error
    	final ArrayList<String> todoItems = new ArrayList<String>();
    	final ArrayAdapter<String> aa;
    	aa = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,todoItems);
    	myListView.setAdapter(aa);
    	myEditText.setOnKeyListener(new OnKeyListener()
    	{
    		public boolean onKey(View v, int keyCode, KeyEvent event)
    		{
    			if (event.getAction() == KeyEvent.ACTION_DOWN)
    				if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER)
    				{
    					todoItems.add(0, myEditText.getText().toString());
    					aa.notifyDataSetChanged();
    					myEditText.setText("");
    					return true;
    				}
    			return false;
    		}
    	});
    	}
}

  

and following in my main.xml file

  

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
  
    <EditText
    android:id="@+id/myEditText"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="New To Do Item"
    />
    
<ListView 
	android:id="@+id/myListView" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    />
</LinearLayout>

But when I tried to run the program I got 3 error as "R can not be resolved" at shown above.



I had to find out solution for this but my problem is not solved. Some forum says make another program and run it. I tried it for 3 times but every time I got same error as "R can not be resolved". Please help me.

Thank you

[Ksh Aggarwal]

This error is because eclipse cannot find 'R.java' file.

You have to import the 'R.java' file manually since eclipse has not done so itself.

[Pramod P Deore]

Hello ksh I had import the file but still i get 2 errors.

Thanks for reply

[Ksh Aggarwal]

Pramod P Deore wrote:Hello ksh I had import the file but still i get 2 errors.

Could you please specify the import you made and the errors?

[Pramod P Deore]

I had imported as

   
import com.micro.R;

 

but it still gives 2 errors as "R.id can not be resolved"

Thanks

[Ksh Aggarwal]

It seems to be some eclipse issue. Try restarting the IDE. There is not much more i can help you with this problem.

[Pramod P Deore]

Hello Ksh,
I don't know how but erros are now solved but now on emulator following error is generated as
"The application NewApp(process com.micro) has stopped unexpectedly. Please try again".
and "Force clode" button is displayed.

Thanks

[Ksh Aggarwal]

Check the logcat of the emulator. your application has encountered some error. you can find the exception stack trace in the logcat

[Pramod P Deore]

I am not getting any clue from Error.Log file.

[Ksh Aggarwal]

You have to veiw the logcat in DDMS. its a view option in eclipse. select the emulator from the left and see the logcat window for the logs created by emulator

[Pramod P Deore]

sorry for silly questions, but will you please tell me how to view logcat in DDMS. I can't find view option in eclipse.

Thanks

[Ksh Aggarwal]

go to Window>Open perspective>others. Select DDMS
There you have devices window on left and LogCat window at bottom. Select the emulator from device window nd you can then veiw the logs in LogCat window. This is where all your logs (error trace and println commands) will be shown.
Use it for some time. U'll get used to it

[Pramod P Deore]

Thanks Ksh,

for your help, now I am able to open Logcat but I didin't get any clue.

[Ksh Aggarwal]

Pramod P Deore wrote:
for your help, now I am able to open Logcat but I didin't get any clue.

Now run the application again and see the logcat as the application progresses. an error in application will create a error trace in red color in logcat.

[Pramod P Deore]

ok wait for 5 min

[Pramod P Deore]

I got following error messages , I am sending only red colour (error) messages..

  

01-11 13:02:00.311: ERROR/mountd(19): could not read initial mass storage state

01-11 13:02:00.561: ERROR/flash_image(28): can't find recovery partition


01-11 13:02:06.982: ERROR/MemoryHeapBase(46): error opening /dev/pmem: No such file or directory

01-11 13:02:06.992: ERROR/SurfaceFlinger(46): Couldn't open /sys/android_power/wait_for_fb_sleep or /sys/android_power/wait_for_fb_wake
01-11 13:02:07.021: ERROR/GLLogger(46): couldn't load <libhgl.so> library (Cannot find library)

01-11 13:02:09.052: ERROR/BatteryService(46): Could not open '/sys/class/power_supply/usb/online'
01-11 13:02:09.052: ERROR/BatteryService(46): Could not open '/sys/class/power_supply/battery/batt_vol'
01-11 13:02:09.052: ERROR/BatteryService(46): Could not open '/sys/class/power_supply/battery/batt_temp'

01-11 13:02:09.231: ERROR/System(46): Failure starting core service
01-11 13:02:09.231: ERROR/System(46): java.lang.SecurityException
01-11 13:02:09.231: ERROR/System(46):     at android.os.BinderProxy.transact(Native Method)
01-11 13:02:09.231: ERROR/System(46):     at android.os.ServiceManagerProxy.addService(ServiceManagerNative.java:146)
01-11 13:02:09.231: ERROR/System(46):     at android.os.ServiceManager.addService(ServiceManager.java:72)
01-11 13:02:09.231: ERROR/System(46):     at com.android.server.ServerThread.run(SystemServer.java:155)
01-11 13:02:09.231: ERROR/AndroidRuntime(46): Crash logging skipped, no checkin service

01-11 13:02:09.262: ERROR/EventHub(46): could not get driver version for /dev/input/mouse0, Not a typewriter
01-11 13:02:09.292: ERROR/EventHub(46): could not get driver version for /dev/input/mice, Not a typewriter

01-11 13:02:09.452: ERROR/SystemServer(46): Failure starting StatusBarService
01-11 13:02:09.452: ERROR/SystemServer(46): java.lang.NullPointerException
01-11 13:02:09.452: ERROR/SystemServer(46):     at com.android.server.status.StatusBarPolicy.updateBluetooth(StatusBarPolicy.java:762)
01-11 13:02:09.452: ERROR/SystemServer(46):     at com.android.server.status.StatusBarPolicy.<init>(StatusBarPolicy.java:285)
01-11 13:02:09.452: ERROR/SystemServer(46):     at com.android.server.status.StatusBarPolicy.installIcons(StatusBarPolicy.java:341)
01-11 13:02:09.452: ERROR/SystemServer(46):     at com.android.server.ServerThread.run(SystemServer.java:182)
01-11 13:02:09.452: ERROR/AndroidRuntime(46): Crash logging skipped, no checkin service

01-11 13:02:09.652: ERROR/GpsLocationProvider(46): Could not open GPS configuration file /etc/gps.conf
01-11 13:02:09.652: ERROR/GpsLocationProvider(46): java.io.FileNotFoundException: /etc/gps.conf
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at org.apache.harmony.luni.platform.OSFileSystem.open(OSFileSystem.java:227)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at java.io.FileInputStream.<init>(FileInputStream.java:76)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at com.android.internal.location.GpsLocationProvider.<init>(GpsLocationProvider.java:179)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at com.android.server.LocationManagerService._loadProvidersNoSync(LocationManagerService.java:356)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at com.android.server.LocationManagerService.loadProvidersNoSync(LocationManagerService.java:340)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at com.android.server.LocationManagerService.loadProviders(LocationManagerService.java:333)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at com.android.server.LocationManagerService.<init>(LocationManagerService.java:447)
01-11 13:02:09.652: ERROR/GpsLocationProvider(46):     at com.android.server.ServerThread.run(SystemServer.java:235)
01-11 13:02:09.652: ERROR/AndroidRuntime(46): Crash logging skipped, no checkin service

01-11 13:02:14.896: ERROR/NetworkStateTracker(46): net.tcp.buffersize.unknown not found in system properties. Using defaults
01-11 13:02:14.896: ERROR/NetworkStateTracker(46): Can't set tcp buffer sizes:java.io.FileNotFoundException: /sys/kernel/ipv4/tcp_rmem_min

01-11 13:02:20.766: ERROR/dalvikvm(173): pthread_setspecific failed, err=22

01-11 13:02:21.765: ERROR/AndroidRuntime(195): Uncaught handler: thread main exiting due to uncaught exception
01-11 13:02:21.785: ERROR/AndroidRuntime(195): android.app.SuperNotCalledException: Activity {com.micro/com.micro.NewApp} did not call through to super.onCreate()
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2157)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.app.ActivityThread.access$1800(ActivityThread.java:112)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1581)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.os.Handler.dispatchMessage(Handler.java:88)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.os.Looper.loop(Looper.java:123)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at android.app.ActivityThread.main(ActivityThread.java:3739)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at java.lang.reflect.Method.invokeNative(Native Method)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at java.lang.reflect.Method.invoke(Method.java:515)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:497)
01-11 13:02:21.785: ERROR/AndroidRuntime(195):     at dalvik.system.NativeStart.main(Native Method)

  

[Ksh Aggarwal]

Error in your application is reported in line 54

android.app.SuperNotCalledException: Activity {com.micro/com.micro.NewApp} did not call through to super.onCreate() 

add

  super.onCreate(savedInstanceState);  

as the first statement in your onCreate method to remove this error

[Pramod P Deore]

Thanks Ksh,
It works