How to call methods in onCreate (when the app starts)

Question

I have MainActivity.class that has some methods. Here is the method I want to call when the app starts:

public void loadGame(View view) {
    SharedPreferences loadGame = getSharedPreferences(PREFS, MODE_PRIVATE);         
    cashView.setText("cash: " + String.valueOf(cash));
    levelView.setText("level: " + String.valueOf(level));
}

So I try to type in the following in my onCreate method:

loadGame();

But I get an error: (View) in MainActivity cannot be applied to ()

Sorry for such a silly question but I don't get it. I thought that onCreate and other activity methods are similar to main method in Java (but they are not), but still I can easily assign a method for Button onClick. Why can't I call a method when the app starts? Any solution?

upd: MainActivity code:

public class MainActivity extends AppCompatActivity {
    private int cash = 1000;
    private int level = 1;
    private TextView cashView;
    private TextView levelView;

    public static final String PREFS = "MySavedGameFile";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

     //the compiler says it cannot resolve symbol 'view'
     //  loadGame(view);
     //I need to call the method anyway
        cashView = (TextView) findViewById(R.id.cashView);
        levelView = (TextView) findViewById(R.id.levelView);

    }
     public void loadGame(View view) {
        SharedPreferences loadGame = getSharedPreferences(PREFS, MODE_PRIVATE);
        cash = loadGame.getInt("savedCash", 1000);
        level = loadGame.getInt("savedLevel", 1);
        cashView.setText("Cash: " + String.valueOf(cash));
        levelView.setText("Level: " + String.valueOf(level));

You can call method in onCreate, can you post the full onCreate method — Chol, Feb 29 '16 at 16:38
Curious as to why do you need to pass in view for this method? Remove the parameter and just call the function without params. — Shobhit Puri, Feb 29 '16 at 16:40
instead of public void loadGame(View view) put public void loadGame() — Chol, Feb 29 '16 at 16:40
*post your error stacktrace.* obviously there is no stacktrace ... it is a compile time error — Selvin, Feb 29 '16 at 16:41
I suspect you are calling `.setText` before initializing your views. — giannisf, Feb 29 '16 at 16:42
@ShobhitPuri, no way. It says "Cannot resolve symbol 'loadGame' " — Nicolai Stoianov, Feb 29 '16 at 16:43
you have signature : public void loadGame(View view) why you try to call method without vew parameter? in your method view is not used delete it from signature than — Konstantin Volkov, Feb 29 '16 at 16:43
@Chol in that case (if I remove View view) the app crashes when the method is called. — Nicolai Stoianov, Feb 29 '16 at 16:51
Assuming this is an `onClick` function (guessing by the way it is set up) you can initialize your button then call `buttonName.performClick()` — codeMagic, Feb 29 '16 at 16:54

score 1 · Accepted Answer · edited Jun 20 '20 at 09:12

1

The problem your code is that you are defining a method with a signature but using another for calling it..

if you define a method public void loadGame(View view) then you need to call it like loadGame(view)

if you do something like loadGame(); then the compiler is going crazy because he can not find that method (a method without parameters...)

Quickfix:

replace add the view(whatever it is) to the method call

Update:

you can replace the method public void loadGame(View view) { for this public void loadGame( ) { because you are not using any view in that method and in the oncreate there is no view (except for the controls cashView and levelView but those are Activity fields... ) declared.

Your final code should look like:

 ...
  @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        cashView = (TextView) findViewById(R.id.cashView);
        levelView = (TextView) findViewById(R.id.levelView);
        loadGame( );

    }
     public void loadGame() {
        SharedPreferences loadGame = getSharedPreferences(PREFS, MODE_PRIVATE);
        cash = loadGame.getInt("savedCash", 1000);
        level = loadGame.getInt("savedLevel", 1);
        cashView.setText("Cash: " + String.valueOf(cash));
        levelView.setText("Level: " + String.valueOf(level));
      }

edited Jun 20 '20 at 09:12

Community

1
1

answered Feb 29 '16 at 16:48

ΦXocę 웃 Пepeúpa ツ

47,427
17
69
97

Hm.. Even in that case it says "Cannot resolve symbol 'view'" I called the method like this: loadGame(view); – Nicolai Stoianov Feb 29 '16 at 16:56
perfect, I saw the update and I modify my answer too... just remove the view in the method... – ΦXocę 웃 Пepeúpa ツ Feb 29 '16 at 17:08
unfortunately, that View is needed. Without it the app crashes because it cannot recognize the TextViews to set text. So without it the app crashes, but with it the compiler gets crazy – Nicolai Stoianov Feb 29 '16 at 17:18
No @NikolayS. just move the loadGame(); just after your Textview and editText instructions, otherwiese you will get a nullpointer exception – ΦXocę 웃 Пepeúpa ツ Feb 29 '16 at 17:19
I added a new code at the end of my answer... this works! – ΦXocę 웃 Пepeúpa ツ Feb 29 '16 at 17:23
wow! I understood my problem at last. I just called the method in the wrong place, when the TextViews were not initialized yet. That caused the app crash. Thank you! – Nicolai Stoianov Feb 29 '16 at 17:26

score 0 · Answer 2 · answered Feb 29 '16 at 16:53

0

You need to pass a View object as an argument to the loadGame() method. Considering you do not use view in your method, instead you can just remove it as a parameter, or create a new method of the same name with no parameters.

answered Feb 29 '16 at 16:53

vontell

342
3
17

How to call methods in onCreate (when the app starts)

2 Answers2

Quickfix:

Update:

Your final code should look like: