Array copy to Array Java Android example

"id cannot be resolved or is not a field” error
If you copy project to workspace or some code from other project you can get this error.

Try remove or add import your R file:

import com.example.app.R

Check xml files.
Clean project by menu Project-Clean

Maybe you have to create new project end copy old source files to new project folders.

Problem: erroneous entry of id

<RadioButton android:id="idRadio"
                android:text="My radio button"/>

Solution: @+id/

<RadioButton android:id="@+id/idRadio"
                android:text="My radio button"/>

Try some solution - each individually or all

1. Check AndroidManifest.xml activity declaration
   

   <activity
               android:name=".EnableProfileActivity"
               android:label="@string/app_name" />

   
   


2. Delete BUILD folder in module tree and Clean / Rebuild project


3. Restart Android Studio

To hide a module File->Project Structure Ctrl+Alt+Shift+S
In left panel click on Module which want to hide.
Click on minus symbol (-) on upper left corner of window.
Click Yes.

To delete module from disk click on module in project tree (to select) and press Delete on keyboard.

Android app setup preferences, settings, open, read, write, onStop(), onPause(), getSharedPreferences(), SharedPreferences.Editor getInt(), getBoolean(), getString() , putInt(), putString(), putBoolean() example source code.

import android.content.SharedPreferences;

public class MainClass extends Activity {
  public static final String PREFERENCES_NAME = "MyPrefsFile";
  String myNewString;
  int myNewInt;
  Boolean myNewBool;


   @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // read old settings if exist
      SharedPreferences settings = getSharedPreferences(PREFERENCES_NAME, 0);
			
     String sDefault = "Hello!";
      String sStringFromPrefFile = settings.getString("myString", sDefault); // new text  or default Hello!
          
      int nDefaultIndex = 2; //
      int nIndexFromPrefFile = settings.getInt("myInt", nDefaultIndex); // 4 or default 2
			
      Boolean bDefault = false;
      Boolean bFromPrefFile = settings.getBoolean("silentMode", bDefault); // true or default false
        
        
        // new settings will saved in onStop or onPause
        myNewString = "new text";
        myNewInt = 4;
        myNewBool = true;
     }   

    @Override
    protected void onPause() {
    	super.onPause();
        Toast.makeText(getApplicationContext(), "onPause "
        		, Toast.LENGTH_SHORT).show();

    	savePreferences();
    }
    
    @Override
    protected void onStop() {
    	super.onStop();
    	savePreferences();
    }
    /**save settings*/	
    public void savePreferences(){
    	try {
    		SharedPreferences settings = getSharedPreferences(PREFERENCES_NAME, 0);
    		SharedPreferences.Editor editor = settings.edit();
 
    		editor.putString("myString", myNewString);
     		editor.putInt("nMyInt", myNewInt);
    		editor.putBoolean("silentMode", myNewBool); // 
    		
    		editor.commit();
    	} catch (Exception e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    	
    }	
}