將數據傳遞到另一個活動

Question

因此，我試圖從一項活動的另一項傳遞一些數據，但這樣做有一些困難。

這是代碼：

private TextView createNewTextView (String text){
    final LayoutParams lparams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    final TextView newTextView = new TextView(this);
    ArrayList<String> players = new ArrayList<String>();
    Intent zacniIgro = getIntent();

    newTextView.setLayoutParams(lparams);
    newTextView.setText(text);
    players.add(text);
    zacniIgro.putStringArrayListExtra("players", players);
    return newTextView;
}

public void zacniIgro (View v){
    Intent zacniIgro = new Intent (getApplicationContext(), Igra.class);
    startActivity(zacniIgro);
}

現在如何獲得新活動中的數據？ 我試過了但是沒用

ArrayList<String> players = data.getStringArrayListExtra("players");

任何想法我還能怎么做？

檢索列表：

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

    ArrayList<String> players = data.getStringArrayListExtra("players");
}

紅色強調了“數據”，因此我很確定“數據”有問題嗎？

Answer 1

問題是您在開始新活動時正在創建新的意圖。 嘗試這個 ：

ArrayList<String> players = new ArrayList<String>(); //declare it outside of the function

private TextView createNewTextView (String text){
    final LayoutParams lparams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    final TextView newTextView = new TextView(this);

    newTextView.setLayoutParams(lparams);
    newTextView.setText(text);
    players.add(text);
    return newTextView;
}

public void zacniIgro (View v){
    Intent zacniIgro = new Intent (getApplicationContext(), Igra.class);
    zacniIgro.putStringArrayListExtra("players", players);
    startActivity(zacniIgro);
}

在其他活動上：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_igra);
    Intent data = getIntent();
    ArrayList<String> players = data.getStringArrayListExtra("players");
}