java - 实例状态未保存

Question

我不明白为什么我的包 SavedInstanceState 在应用程序关闭时没有保存。很可能这只是我不知道的愚蠢事情!主要 Activity 没有太多内容，只是一个用于转换屏幕的页面适配器，因为这是我要尝试制作的主要部分。现在大部分代码都在我的 StandFragment.java 中，它是打开应用程序时显示的第一个页面。这就是保存状态之类的地方。

主要 Activity : 公共(public)类 MainActivity 扩展 FragmentActivity {

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

    ViewPager pager = (ViewPager) findViewById(R.id.viewPager);
    pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));       
}

private class MyPagerAdapter extends FragmentPagerAdapter {

    public MyPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int pos){
        switch(pos){
        case 0: return StandFragment.newInstance("STAND");
        case 1: return CartFragment.newInstance("CART");
        case 2: return ThirdFragment.newInstance("THIRD");
        case 3: return ThirdFragment.newInstance("FOURTH");
        case 4: return ThirdFragment.newInstance("FIFTH");
        default: return ThirdFragment.newInstance("Default");
        }
    }

    @Override
    public int getCount(){
        return 5;
    }
}

}

支架 fragment :

      public class StandFragment extends Fragment{

private int totalMoney;
private int moneyPerSec;
private int moneyPerClick;
Handler handleCounter = new Handler();
TextView counter;
TextView perSecCounter;
Button buttonMoney;
Button buttonMoneyPerSec;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
    View v = inflater.inflate(R.layout.stand_frag, container, false);
    super.onCreate(savedInstanceState);

    buttonMoney = (Button)v.findViewById(R.id.buttonMoney);
    buttonMoneyPerSec = (Button)v.findViewById(R.id.buttonMoneyPerSec);
    counter = (TextView)v.findViewById(R.id.tvMoney);
    perSecCounter = (TextView)v.findViewById(R.id.tvMonPerSec);

    TextView tv = (TextView) v.findViewById(R.id.tvStandFrag);
    tv.setText(getArguments().getString("msg"));

    handleCounter.post(updateCounter);
    if (savedInstanceState==null){
        moneyPerSec = 1;
        moneyPerClick = 1;
        totalMoney=0;
    }
    else{
        moneyPerSec = savedInstanceState.getInt("moneyPerSec");
        moneyPerClick = savedInstanceState.getInt("moneyPerClick");
        totalMoney = savedInstanceState.getInt("totalMoney");
    }

    buttonMoney.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            totalMoney += moneyPerClick;
            counter.setText(""+totalMoney);
            perSecCounter.setText(""+moneyPerSec);
        }
    });
    buttonMoneyPerSec.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            if (totalMoney>=10){
                totalMoney-=10;
                counter.setText(""+totalMoney);
                moneyPerSec++;
                perSecCounter.setText(""+moneyPerSec);
            }
        }
    });
    return v;
}

Runnable updateCounter = new Runnable(){
    public void run(){
        totalMoney += moneyPerSec;
        counter.setText(""+totalMoney);
        handleCounter.postDelayed(this, 1000);
    }
};
public void onPause(Bundle savedInstanceState){
    savedInstanceState.putInt("totalMoney",totalMoney);
    savedInstanceState.putInt("moneyPerSec",moneyPerSec);
    savedInstanceState.putInt("moneyPerClick",moneyPerClick);
    super.onSaveInstanceState(savedInstanceState);

}
public static StandFragment newInstance(String text){

    StandFragment f = new StandFragment();
    Bundle b = new Bundle();
    b.putString("msg", text);

    f.setArguments(b);

    return f;
}
}

Answer 1

onSaveInstanceState() 不适用于持久存储。它仅用于保存有关 Fragment 实例的特定状态(例如，在配置更改期间，或者您的应用程序在后台被终止并且应重新创建 Fragment)。如果您完全关闭应用程序(即完成 Activity)，那么您的状态将不会被保存，因为不再需要该实例。

对于持久存储，您可以根据需要查看 SharedPreferences 或 SQLite。