CODEWITHSUNDEEP
javaandroidglobal-variables
bsquared
bsquared

Reputation: 137

Global Class/ variables not saving by setter

I am attempting to use a global class to make the object data available through all of my activities. In my first activity, I am initializing my global class patient, and setting the variable with setPatientName. In my next activity, I call 'getPatientName', but it is returning null. When I try to set the result of 'getPatientName', it gives me the error

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference

EDIT: My first activity is collecting the name from a text field, and that is what i'm trying to setPatientName as

The first activity:

 tv2=(TextView)findViewById(R.id.textView2);

 EditText name = (EditText) findViewById(R.id.textView2);
    String nameString = name.getText().toString();

 final Patient p = (Patient) getApplicationContext();
    p.setPatientName(nameString);

The Second Activity:

Patient p = (Patient)getApplication();
String patName = p.getPatientName();
tv2.setText(patName);

The Patient class:

package com.example.imac.chs_pharmacy;

import android.app.Application;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.Log;

public class Patient extends Application {

    //private variables
    public String patient_name;

    //default constructor
    public Patient(){
    }

    public Patient(String startPatientName) {
        this.patient_name = startPatientName;
    }

    public void setPatientName( String patientName ){
        Log.d(TAG, "setting patient name");
        this.patient_name = patientName;
    }

    public String getPatientName( ){
        Log.d(TAG, "getting patient name");
        return this.patient_name;
}

manifest.xml:

<application android:name="com.example.imac.chs_pharmacy.Patient"

It's also worth noting that in my Patient class, i'm logging out a string in my getPatientName and setPatientName, but it only seems to be logging on the setPatientName. Is my setPatientName not getting fired off for some reason?

Upvotes: 0

Views: 448

Answers (2)

arjun
arjun

Reputation: 3574

There is no need of extending Application. Try as below

public class Patient {

private static Patient patientInstance;

private String patient_name;

//private contrunctor to prevent from creating patient instance directly through constructor.
private Patient() {
}

public static Patient getInstance() {
  if (patientInstance == null) {
    patientInstance = new Patient();
  }
  return patientInstance;
}

public void setPatientName( String patientName ){
  this.patient_name = patientName;
}

public String getPatientName( ){
  return this.patient_name;
}
}

Then use the class as below

Patient p = Patient.getInstance();
String patName = p.getPatientName();
TextView tv2 = (TextView) findViewById(R.id.your_text_view_id);
tv2.setText(patName);

Upvotes: 1

Volli
Volli

Reputation: 61

Let's try this solution:

public class Patient extends Application {

//private variables

public String patient_name = "StartPatientName"; 



 //default constructor    you should not ovveride Application class constructor!
 //    public Patient(){
 //    }

//  public Patient(String startPatientName) {
//    this.patient_name = startPatientName;
//}



public void setPatientName( String patientName ){
    Log.d(TAG, "setting patient name");
    this.patient_name = patientName;

}


public String getPatientName( ){
    Log.d(TAG, "getting patient name");
    return this.patient_name;
}

Also in the second activity init tv2 as below:

Patient p = (Patient)getApplication();
String patName = p.getPatientName();
TextView tv2 = (TextView) findViewById(R.id.your_text_view_id);
tv2.setText(patName);

Upvotes: 1

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