Changing TextView from different class

Question

I want to update TextView from another class which is not an activity, but the app keeps crushing.. I hope you can help

This is the class where I want to update text after knowing game result

  public class GameLogic {
    ...
    public void gameResult() {
            OnePlayerGameActivity gameActivity = new OnePlayerGameActivity();
            TextView result = (TextView) gameActivity.findViewById(R.id.game_result_textView);

            getPlayerChoice();

            int computer = computerChoice();

            if (mPlayerChoice == computer) {
                mPlayerStat += 0;
                mOpponentChoice += 0;
            } else if (mPlayerChoice == 1) { //ROCK
                switch (computer) {
                    case 1: //ROCK

                        break;
                    case 2:  //PAPER
                        mOpponentStat ++;
                        result.setText("LOST");
                        break;
    ...

all code can be found on my GitHub

Answer 1

You are creating just a dummy instance of your activity which has no relation with the one in memory, instead pass the activity instance using

// in your OnePlayerGameActivity.java
// inside some method
GameLogic obj = new GameLogic (); // instance of GameLogic for demo
obj.gameResult(OnePlayerGameActivity.this); // pass instance

and change the methods signature as

 public void gameResult(OnePlayerGameActivity gameActivity ) {
            TextView result = (TextView) gameActivity.findViewById(R.id.game_result_textView);