Android Call a method from another class

Question

I know that this Question is repeated but I can't find the answer in the Internet.

I want to call a method from another class.

I have Class1 and Class2.

In Class 2 I have this method:

public void UpdateEmployee(){
    //some code
}

I want to call the above method from Class1.

Thanks for any answer.

----EDIT----

final Button btnUpdate = (Button)findViewById(R.id.btnUpd);
   btnUpdate.setOnClickListener(new View.OnClickListener() {      
     public void onClick(View v) {
             Employee updEmple = new Employee();
             updEmple.UpdateEmployee();      
            
    }
    });

----LogCat---

05-28 16:30:44.030: E/AndroidRuntime(25198): FATAL EXCEPTION: main
05-28 16:30:44.030: E/AndroidRuntime(25198): java.lang.NullPointerException: println    needs a message
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.util.Log.println_native(Native Method)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.util.Log.v(Log.java:116)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at   and.net.Employee.UpdateEmployee(Employee.java:77)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at and.net.AndActivity$2.onClick(AndActivity.java:51)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.view.View.performClick(View.java:2485)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.view.View$PerformClick.run(View.java:9080)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.os.Handler.handleCallback(Handler.java:587)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.os.Looper.loop(Looper.java:123)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at android.app.ActivityThread.main(ActivityThread.java:3683)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at java.lang.reflect.Method.invokeNative(Native Method)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at java.lang.reflect.Method.invoke(Method.java:507)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-28 16:30:44.030: E/AndroidRuntime(25198):    at  dalvik.system.NativeStart.main(Native Method)

show your UpdateEmployee code, the problem is there you're trying to print something that isn't set — eric.itzhak, May 28 '12 at 17:17

score 75 · Accepted Answer · edited Sep 29 '17 at 13:21

75

You should use the following code :

Class2 cls2 = new Class2();
cls2.UpdateEmployee();

In case you don't want to create a new instance to call the method, you can decalre the method as static and then you can just call Class2.UpdateEmployee().

edited Sep 29 '17 at 13:21

Vadim Kotov

8,084
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answered May 28 '12 at 15:42

eric.itzhak

15,752
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On what line and when you are trying to use static or the regular? – eric.itzhak May 28 '12 at 16:20
I'm using it OnClickButton. Employee updEmple = new Employee(); updEmple.UpdateEmployee(); – HaOx May 28 '12 at 16:24
1

Edit your question and publish the logcat – eric.itzhak May 28 '12 at 16:26
It's allmost that simple, yet don't forget in class 2 to add the reference or class 1 won't even compile. public class Class2 extends AppCompatActivity { public Class 2() { } – Wraithious Sep 08 '17 at 18:36
how to get response along with it. – San Daniel May 25 '18 at 12:30

score 8 · Answer 2 · edited Sep 29 '17 at 13:21

8

In Class1:

Class2 inst = new Class2();
inst.UpdateEmployee();

edited Sep 29 '17 at 13:21

Vadim Kotov

8,084
8
48
62

answered May 28 '12 at 15:40

Parag Chauhan

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score 6 · Answer 3 · answered May 28 '12 at 15:42

6

And, if you don't want to instantiate Class2, declare UpdateEmployee as static and call it like this:

Class2.UpdateEmployee();

However, you'll normally want to do what @parag said.

answered May 28 '12 at 15:42

Charlie-Blake

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normally... because you won't be able to access the variables otherwise. – FlorianB Oct 17 '16 at 22:51

score -7 · Answer 4 · answered May 18 '15 at 05:45

-7

Add this in MainActivity.

Intent intent = new Intent(getApplicationContext(), Heightimage.class);
startActivity(intent);

answered May 18 '15 at 05:45

Jessie Ka

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1

This is not calling for class.This is "starting" to an class. – Op.Kemal Feb 07 '20 at 13:35
I dont care call or stariting it open new class :D – Cornea Valentin Feb 08 '23 at 14:08

Android Call a method from another class

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