java - Android variable availability (can not be resolved)

Question

While trying to run my app, I noticed that a few errors claiming that many variables can not be resolved, even though declared in the code i changed it to the following code, but once I enter the app, it collapses:

public String GetErr(){

        String error="";
        if(Facebook_name.toString().equals("")&& Facebook_chk.isChecked())//check with title if not available.
        {
        error+="facebook account not entered/n";//also check if not available
        }
        if(Name.toString().equals(""))
            error+="Name not entered/n";
        if(Id.toString().contains("[a-zA-Z]+") || Id.toString().equals(""))
            error+="Id entered is invalid/n";
        if(Pass.toString().length()<5 || Pass.toString().equals(""))
            error+="Passwords must contain 5 or more digits";
    //  int day= Date.getDayOfMonth();
    //  int month = Date.getMonth();
    //  int year=Date.getYear();
        //Calendar enter = Calendar.getInstance();
    //  Calendar today = Calendar.getInstance();
    //  enter.set(year,month,day);
    //  today.set(Calendar.YEAR,Calendar.MONTH,Calendar.DAY_OF_MONTH);
        //if((enter.getTime().before(today.getTime())))
        //  error+="Date entered either passed or not available.";

        return error;
}

EDIT: Now the geterr() returns an empty string at all times.

Answer 1

You are declaring variables in the onCreate() method, so that is their scope. You can not use them outside this function. So when you use them in the GetErr() method, you get an error. You can solve this by moving the variables you need in multiple methods to global variables (so declare them in the class instead of in the method.

Edit

package com.example.app;


//import java.util.Calendar;

import android.app.Activity;
import android.os.Bundle;

import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
//import android.widget.DatePicker;

import android.widget.TextView;

public class Second extends Activity implements OnClickListener {
    CheckBox Facebook_chk;
    TextView Facebook_name;
    TextView Name;
    TextView Id;
    TextView Txterr;
    TextView Pass;

    Button Btn1;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.second);
        Btn1 = (Button) findViewById(R.id.Btn1);
        Facebook_chk = (CheckBox)findViewById(R.id.Cfbook);//Represents the facebook checkbox.
        Facebook_name = (TextView)findViewById(R.id.Face);//represents the facebook text.
        Name = (TextView)findViewById(R.id.Name);//represents the Name text.
        Id = (TextView)findViewById(R.id.Id);//represents the Id text.
        Txterr = (TextView)findViewById(R.id.Txterr);//represents the Id text.
        Pass = (TextView)findViewById(R.id.Pass);//represents the Pass text.


        Btn1.setOnClickListener(this);
        Facebook_chk.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){

            @Override
            public void onCheckedChanged(CompoundButton buttonView,
                                         boolean isChecked) {
                // TODO Auto-generated method stub
                if(Facebook_chk.isChecked())
                    Facebook_name.setEnabled(true);
                else
                    Facebook_name.setEnabled(false);
                ;
            }
        });

    }


    public String GetErr(){

        String error="";
        if(Facebook_name==null && Facebook_chk.isChecked())//check with title if not available.
        {
            error+="facebook account not entered/n";//also check if not available
        }
        if(Name==null)
            error+="Name not entered/n";
        if(Id.toString().contains("[a-zA-Z]+") || Id==null)
            error+="Id entered is invalid/n";
        if(Pass.toString().length()<5)
            error+="Passwords must contain 5 or more digits";
        //  int day= Date.getDayOfMonth();
        //  int month = Date.getMonth();
        //  int year=Date.getYear();
        //Calendar enter = Calendar.getInstance();
        //  Calendar today = Calendar.getInstance();
        //  enter.set(year,month,day);
        //  today.set(Calendar.YEAR,Calendar.MONTH,Calendar.DAY_OF_MONTH);
        //if((enter.getTime().before(today.getTime())))
        //  error+="Date entered either passed or not available.";

        return error;
    }
    @Override
    public void onClick(View v) {
        if(v == Btn1){
            String err = GetErr();
            if(err != ""){
                Txterr.setText(err);
            }
        }
    }

}