How to use java classes within one activity?

Question

How can you use a java class within one activity, by that I mean is having different components of that activity spread out in a bunch of java classes. I\'m a little new to andr

Answer 1

I think that you should rearrange the code to have the onClickListener inside Something constructor:

Something.java

import android.view.View;
import android.widget.EditText;
import android.widget.Button;
import android.app.Activity;

public class Something {

    private Activity activity;
    private Button add, subtract, multiply, devide;
    private EditText editA, editB, editC;
    private double doubleA, doubleB, doubleC;

    public Something(Activity a) {

        activity = a;

        editA = (EditText) activity.findViewById(R.id.editText);
        editB = (EditText) activity.findViewById(R.id.editText2);
        editC = (EditText) activity.findViewById(R.id.editText3);

        add = (Button) activity.findViewById(R.id.add);
        subtract = (Button) activity.findViewById(R.id.subtract);
        multiply = (Button) activity.findViewById(R.id.multiply);
        devide = (Button) activity.findViewById(R.id.devide);

        add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                click(1);

            }
        });

        subtract.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                click(2);

            }
        });

        multiply.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                click(3);
            }
        });

        devide.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                click(4);
            }
        });
    }


    public void click(int calculate) {

        // assume number entered - no error
        doubleA = Double.parseDouble(editA.getText().toString());
        doubleB = Double.parseDouble(editB.getText().toString());

        switch (calculate) {

            case 1:
                doubleC = doubleA + doubleB;
                String s = "" + doubleC;
                editC.setText(s);
                break;

            case 2:
                doubleC = doubleA - doubleB;
                String s = "" + doubleC;
                editC.setText(s);
                break;

            case 3:
                doubleC = doubleA * doubleB;
                String s = "" + doubleC;
                editC.setText(s);
                break;

            case 4:
                doubleC = doubleA / doubleB;
                String s = "" + doubleC;
                editC.setText(s);
                break;

            default:
                break;

        }

    }

}

I think the problem was putting 'click()' method inside the main constructor runs through the code once only. I hope this helps!

Answer 2

As I know this will help someone else who encountered the same problem as me will benefit, the problem was that I needed to pass the activity into my Something(Activity a){} constructor and initialize everything into that. Like Something(Activity a){
aT1 = (EditText) a.findViewById(R.id.numberOne); aT2 = (EditText) a.findViewById(R.id.numberTwo); aT3 = (EditText) a.findViewById(R.id.result); add = (Button) a.findViewById(R.id.add); subtract = (Button) a.findViewById(R.id.subtract); multiply = (Button) a.findViewById(R.id.multiply); devide = (Button) a.findViewById(R.id.devide); }

And all you need to do in main activity is pass the Activity when you make an instance/execute the code(ex: Something s = new Something(this);/new Something(this);) After you done that you can just call s.click(); and it should work.

Answer 3

You can use your "something" class in the mainactivity.

first initialize "Something" class in the main activity by

Something s = new Something(MainActivity.this);

Than you can use every method of that class in your main Activity.Just as you wanted,like this

s.add.setonclicklistener(...

or

s.click();
//Just use like this.

Answer 4

like a before post XD with 1 java class, call it again after pressing buttons, for example, you can have a invisible buttons, radiobuttons whatever you want invisible and just with a click it turns visible and useful for you, here i go:

First the variable which controls the activity are going to do

String num ="";

then have your buttons, i use 2 of them and the others are invisible

Button bn1;
Button bn2;
Button bn3;
Button bn4;
bn3.setVisibility(View.INVISIBLE);
bn4.setVisibility(View.INVISIBLE);

then the button code, depends on how many buttons you want

Button.setOnClickListener(new Button onclickListener(){
        public void onClick(){
            //get a default variable in this case String num
    Intent intent = new Intent(MainActivity.this, MainActivity.class); num="cero"; intent.putExtra("po", num);
                        CodigoPeticion=2; startActivityForResult (intent,CodigoPeticion); finish(); break;
                }
            }
        });

this one to get the String num:

Bundle extras = getIntent().getExtras();
        if (extras!= null) {
            num =extras.getString("po");
        }

and at last but not least this one to do someting depending the String:

    if (num.matches("cero")){
                //do something, enable more buttons, disable radiobuttons,
bn3.setVisibility(View.VISIBLE);
            }else if(num.matches("one")){//this string is from another button
                //do something else in the same activity, as you spected enable radiobuttons, show a image, etc
bn4.setVisibility(View.VISIBLE);
            }else{
                //some textview with a specific title
                TextView.setText("Something's Wrong");
            }

don't forget the bn3 and bn4 listeners!

hope that helps you, see ya!