将变量从Java类传递给Android的另一个

Question

Screen2.java file has the following code :

public class screen2 extends Activity {

    public int globalZip=0;
        //Some validations & update globalZip
        //Code control goes to Screen3,java

}

Screen3.java file has the following code :

public class Screen3 extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.screen3);
        screen2 objs2= new screen2();
        int myzip = objs2.globalZip;

        Toast.makeText(getBaseContext(), "Screen3 "+myzip, 5).show();

        System.out.println("WTHDude"+"Screen3 "+myzip);

    }

Now the problem i am having that if i have updated value of globalZip in Screen2.java file as 90034 it is not getting updated in the screen3. Can anyone help me with this error. Thank you.

Answer 1

Well, you're creating a new instance of Screen2, so of course you will return the initial value of globalZip since it is not a static class member.

Saying that, you probably don't really want it to be a static member anyway.

But more importantly you're going about this completely wrong. If you want to pass data from one Activity to another Activity you just need to, for simple data like Strings/booleans/ints, add it to the Intent that starts Screen3.

Something like this:

// inside Screen2.java
Intent intent = new Intent(this, Screen3.class);
intent.putExtra("screen2.globalzip", globalZip);

And then to get the value in Screen3.java:

Bundle extras = getIntent().getExtras();
int globalZip = extras.getInt("screen2.globalzip");

Answer 2

Use intents for passing data between activities. Here is and example.