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Java InstanceState未保存_Java_Android - Fatal编程技术网

Java InstanceState未保存

Java InstanceState未保存,java,android,Java,Android,我不明白为什么应用程序关闭时我的捆绑包SavedInstanceState没有保存。很可能这只是我不知道的愚蠢的事情!主活动中没有太多内容,只是一个用于转换屏幕的页面适配器,因为这是我将尝试制作的主要部分。现在大部分代码都在my StandFragment.java中,这是打开应用程序时显示的第一个页面。这就是保存状态和类似的东西 主要活动: 公共类MainActivity扩展了FragmentActivity{ @Override protected void onCreate(Bundle

我不明白为什么应用程序关闭时我的捆绑包SavedInstanceState没有保存。很可能这只是我不知道的愚蠢的事情!主活动中没有太多内容,只是一个用于转换屏幕的页面适配器,因为这是我将尝试制作的主要部分。现在大部分代码都在my StandFragment.java中,这是打开应用程序时显示的第一个页面。这就是保存状态和类似的东西

主要活动: 公共类MainActivity扩展了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;
    }
}
}

标准碎片:

      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;
}
}
仅当Android系统可能需要重新创建片段的特定实例时,才会调用onSaveInstanceState()

您必须将数据保存在活动的onSaveInstanceState()上

onSaveInstanceState()
不用于持久存储。它仅用于保存有关片段实例的特定状态(例如,在配置更改期间,或者如果您的应用程序在后台被杀死,则应重新创建片段)。如果您完全关闭应用程序(即完成
活动
),则不会保存您的状态,因为不再需要该实例


对于持久存储,您可以根据需要查看
SharedReferences
SQLite

好的,谢谢!出于某种原因,我认为保存实例状态会传递变量。还有一个问题,比如说保存一个按钮的状态是否有效?比如它是否可见?是的,但仅适用于片段的实例(因此,如果旋转应用程序,可以保留并保存一个布尔值(按钮的状态),然后在
onViewCreated()
中重新应用它)。