How to share variables between classes in java

Question

Possible Duplicate:
Passing data between activities in Android

so I have two activity's, and I need to save one variable in first activity, and use it in the second activity. Can anyone help me? Thanks!

Answer 1

Use something like this:

    Intent intent = new Intent(this, ClassImCalling.class);
    intent.putExtra("variable", myvariable);
    startActivityForResult(intent, int_identifier);

And in the other Activity:

    intent = getIntent();
    var=intent.getStringExtra("variable");

To return to the activity that called it (intent being same as getIntent() above):

    setResult(RESULT_OK, intent);
    finish();

And when you return back to the first Activity:

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == int_identifier) {
        if (resultCode == RESULT_OK) {
            Do suff
        }else if(resultCode == RESULT_CANCELED){
            Action was cancelled :(
        }
    }
}

Answer 2

Keep it simple. In one class you set the variable's value in other class use that class's instance to get it.

public class Activity1 {       

   private String var;

   public Activity1() {
      setVar("some_value");
   }

   public String getVar() {
      return this.var;
   }

   public void setVar(String var) {
      this.var = var;
   }
}

public class Activity2 {
   public void doSmth() {
      Activity1 a = new Activity1();
      String varValue = a.getVar();

   }
}

Answer 3

First Activity:

    ....
    Intent intent = new Intent(this, SecondActivity.class);
    intent.putExtra(Consts.EXTRA_EDIT_MODE_KEY, 123);
    ....
    intent.putExtra(_some_key_, _some_data_);
    intent.putExtra(_some_key_, _some_data_);
    startActivity(intent);

SecondActivity:

    ..... 
    Intent intent = getIntent();
    int mode = intent.getIntExtra(Consts.EXTRA_EDIT_MODE_KEY, -1);
    ...... 

Answer 4

As understand your requirement is to use a variable value in several Activity classes. As they mean they are JAVA classes, so you can use a static variable for your task.

Say you have a class like this,

public class Activity1 extends Activity{
static String name="abc";
}

If you want to use that name variable in a other class, you can use,

public class Activity2 extends Activity{
String name2=Activity1.name;
}

Answer 5

Here's one way of doing it, I guess:

class Class1 {
   private int someValue = 0
   void doSomething(Class2 anotherObj) {
       this.someValue = 1;
       anotherObj.setValue(this.someValue);
   }
}

There's many other ways :)

Answer 6

you can pass the first activity data to second activity using intent.putExtra(yourData);

Answer 7

Make the variable static as it is shared by all classes.

Answer 8

If we use shared preferance we can use this value in any activity.

Here is the code in ManageSharesPrefs:

SharedPreferences myPrefs = this.getSharedPreferences("myPrefs", MODE_WORLD_READABLE);
        SharedPreferences.Editor prefsEditor = myPrefs.edit();
        prefsEditor.putString(MY_NAME, "Sai");
        prefsEditor.putString(MY_WALLPAPER, "f664.PNG");
        prefsEditor.commit();

and retrive value as

SharedPreferences myPrefs = this.getSharedPreferences("myPrefs", MODE_WORLD_READABLE);
        String prefName = myPrefs.getString(MY_NAME, "nothing");
        String wallPaper = myPrefs.getString(MY_WALLPAPER, null);

Answer 9

You can use Bundle object to share a variable across 2 activities. This is how I use it:

(1) First, put the variable as an extra into a bundle. Suppose you have the variable in FirstActivity and you want to send it to SecondActivity, then this is the way to put it(in the FirstActivity):

        String variableValue="x";  // it holds some value which you want to pass to SecondActivity.
        Intent secondIntent = new Intent(view.getContext(), SecondActivity.class);
        Bundle bundleObj = new Bundle();
        bundleObj.putString("variableName", variableValue);
        secondIntent.putExtras(bundleObj);
        startActivityForResult(secondIntent, 0); 

(2) This is how we get it in the SecondActivity(in the onCreate() method):

        Bundle extras = getIntent().getExtras();
        String variableValue = extras.getString("variableName");

** Similarly you can pass the integer and other datatyped values as well.