Question

Hi I am completely new to Android programming and the question I am asking might be something very simple, but I do not have any idea about how to make it work, so kindly bear with me.

I installed android-sdk and related tools from the Android developer site. I followed their instructions to create a HelloWorld app, but I am getting some errors which I don’t understand.

The file MainActivity.java is an auto generated file and I keep getting errors in this file in these places:

@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main); // error in activity_main
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
  getMenuInflater().inflate(R.menu.activity_main, menu); // error in activity_main
   return true;
 }

So I went and tried to look through the generated class file for layout.class and found there is no variable called activity_main there.

Can anyone kindly suggest what to do here? Any help will be deeply appreciated.

The directory structure shows me that I do have the AndroidManifest.xml.

When I try to run the app, I get this specific error:

     AndroidManifest.xml file missing!
     Unknown Android Packaging Problem

These are some of the errors that i am getting when trying to get it running :

        10-10 23:31:11.305: E/Trace(946): error opening trace file: No such file or directory (2)
        10-10 23:31:11.955: E/AndroidRuntime(946): FATAL EXCEPTION: main
        10-10 23:31:11.955: E/AndroidRuntime(946): android.content.res.Resources$NotFoundException: Resource ID #0x2
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.content.res.Resources.getValue(Resources.java:1013)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.content.res.Resources.loadXmlResourceParser(Resources.java:2098)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.content.res.Resources.getLayout(Resources.java:852)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.view.MenuInflater.inflate(MenuInflater.java:107)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at com.example.myfirstapp.MainActivity.onCreateOptionsMenu(MainActivity.java:18)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.app.Activity.onCreatePanelMenu(Activity.java:2476)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java:393)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java:747)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at com.android.internal.policy.impl.PhoneWindow$1.run(PhoneWindow.java:2913)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.os.Handler.handleCallback(Handler.java:615)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.os.Handler.dispatchMessage(Handler.java:92)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.os.Looper.loop(Looper.java:137)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at android.app.ActivityThread.main(ActivityThread.java:4745)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at java.lang.reflect.Method.invokeNative(Native Method)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at java.lang.reflect.Method.invoke(Method.java:511)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        10-10 23:31:11.955: E/AndroidRuntime(946):  at dalvik.system.NativeStart.main(Native Method)

Answer 1

Just build your project or Clean it as “Clayton” mentioned below.

Project > Build All

Project > Clean

This I believe is because you do not have R.java file in your gen folder. Building your project will generate the R.java file in your gen folder and the errors should go away.

This happens because you’re referring to your layout file using the following code

setContentView(R.layout.activity_main); 

The reference to R.layout.activity_main is declared in R.java file which needs to be generated by building your project.