Question

While writing an Android App, when I use TextView in different class(MyClass) other than the main class,
I’m getting an error:

The method findViewById(int) is undefined for the type MyClass

Please tell me the point I’m missing.

Answer 1

MyClass doesn’t extend androids Activity class, therefore you don’t have that method available. So you have to get a reference to use it, preferably through a method argument (never store a activity/context reference in a class member variable, it might result in a memory leak):

Small sample:

class MyActivity extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        MyClass m = new MyClass();
        m.doSomething(this);

        //...
    }
}

And in MyClass

class MyClass {
    public void doSomething(Activity a) {
        View v = a.findViewById(...);
        // do something here ...
    }
}