如何在手机方向上保存我的数据？
问题描述：
我在使应用程序持续存在困难。当我旋转手机时，屏幕上的数据不会改变。但是当我点击一个按钮来检索一个新的片段后，我得到一个错误，说“在onSaveInstanceState之后不能执行这个动作”。我搜索了一下，发现了类似的问题，但我仍然不知道如何解决这个问题。如何在手机方向上保存我的数据？
我有一个活动类，一个控制器类和两个片段类。 活动类有一个带有2个按钮的浏览查看器，可以触发片段交易。也就是说，在每个按钮上单击它将用当前按钮侦听器中设置的片段替换当前片段。我的控制器类创建系统，碎片就是UI。
我的活动类：
public class LoggedInActivity extends AppCompatActivity {
private final String TAG = "LoggedInActivity: ";
private Controller controller;
private TextView navName;
private NavigationView navigationView;
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.v(TAG, "onCreate");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_logged_in);
if(savedInstanceState == null) {
Log.v(TAG, "savedInstanceState == null");
initComponents();
setNavName();
initListener();
initializeSystem();
} else {
Log.v(TAG, "savedInstanceState != null");
initComponents();
setNavName();
initListener();
this.controller = (Controller)savedInstanceState.getSerializable("controller");
}
}
private void initComponents() {
navigationView = (NavigationView) findViewById(R.id.navigation_view);
View headerView = navigationView.getHeaderView(0);
navName = (TextView) headerView.findViewById(R.id.tv_name_surname);
}
private void initListener() {
navigationView.setNavigationItemSelectedListener(new MyNavigationItemListener());
}
private void initializeSystem() {
Log.v(TAG, "new controller");
controller = new Controller(this, null);
}
public void setFragment(Fragment fragment) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.fragment_container_logged_in, fragment).commit();
}
private class MyNavigationItemListener implements NavigationView.OnNavigationItemSelectedListener {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch(item.getItemId()) {
case R.id.drawer_summary:
controller.setFragmentSummary();
break;
case R.id.drawer_income:
controller.setFragmentIncome();
break;
}
return false;
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
outState.putSerializable("controller", controller);
super.onSaveInstanceState(outState);
Log.v(TAG, "onSaveInstanceState, saving the controller");
}
}
我的控制器类：
public class Controller implements Serializable {
private final String TAG = "Controller: ";
/********************** Fragments ***********************/
private Fragment_Income fragment_income;
private Fragment_Summary fragment_summary;
/********************************************************/
/********************** Activities **********************/
private LoggedInActivity logged_in_activity;
/********************************************************/
public Controller(LoggedInActivity logged_in_activity) {
this.logged_in_activity = logged_in_activity;
initLoggedInFragments();
setFragmentSummary();
}
}
/* Initializes fragments that are connected to LoggedInActivity */
private void initLoggedInFragments() {
fragment_income = new Fragment_Income();
fragment_income.setController(this);
fragment_summary = new Fragment_Summary();
fragment_summary.setController(this);
}
/* use to replace current fragment with the given one */
private void replaceFragmentWith(Fragment fragment) {
logged_in_activity.setFragment(fragment);
}
/***********************************************************
* METHODS REGARDING FRAGMENT INCOME *
**********************************************************/
public void setFragmentIncome() {
replaceFragmentWith(fragment_income);
}
/* Summary fragment is started at first */
public void setFragmentSummary() {
replaceFragmentWith(fragment_summary);
}
}
Fragment_Income：
public class Fragment_Income extends Fragment implements Serializable{
private final String TAG = "Fragment_Income: ";
private Controller controller;
private FloatingActionButton fab_income;
private ListView lv_income;
private ArrayList<LvData> incomeData;
private LvAdapterIncome lvAdapterIncome;
public Fragment_Income() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Log.v(TAG, "onCreateView");
View view = inflater.inflate(R.layout.fragment_income, container, false); // Inflate the layout for this fragment
if(savedInstanceState != null) {
this.controller = (Controller) savedInstanceState.getSerializable("controller");
}
initComponents(view);
initListener();
setupListView();
return view;
}
private void initComponents(View view) {
fab_income = (FloatingActionButton) view.findViewById(R.id.fab_income);
lv_income = (ListView) view.findViewById(R.id.lv_income);
}
private void initListener() {
ButtonListener buttonListener = new ButtonListener();
fab_income.setOnClickListener(buttonListener);
}
private void setupListView() {
if (incomeData == null) { // checks if incomeData have been initalized before, if so do not change array to defualt
incomeData = new ArrayList<>();
lvAdapterIncome = new LvAdapterIncome(getContext(), incomeData);
}
lv_income.setAdapter(lvAdapterIncome);
}
public void setController(Controller controller) {
this.controller = controller;
}
@Override
public void onSaveInstanceState(Bundle outState) {
Log.v(TAG, "onSaveInstanceState, saving the controller");
outState.putSerializable("controller", this.controller);
super.onSaveInstanceState(outState);
}
}
Fragment_Summary：
public class Fragment_Summary extends Fragment implements Serializable {
private static final String TAG = "Fragment_Summary: ";
private Controller controller;
private TextView tv_user;
private TextView tv_total_revenue;
private TextView tv_total_expenditure;
private TextView tv_balance;
private float totalRevenue;
private float totalExpenditure;
private float balance;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_summary, container, false);// Inflate the layout for this fragment
initComponents(view);
setUserName();
if(savedInstanceState == null) {
//DO SOMETHING
}
return view;
}
private void addData() {
totalRevenue = controller.getTotalRevenue();
totalExpenditure = controller.getTotalExpenditure();
balance = totalRevenue - totalExpenditure;
tv_total_revenue.setText(String.valueOf(totalRevenue));
tv_total_expenditure.setText(String.valueOf(totalExpenditure));
tv_balance.setText(String.valueOf(balance));
}
private void initComponents(View view) {
tv_user = (TextView)view.findViewById(R.id.tv_user);
tv_total_revenue = (TextView)view.findViewById(R.id.tv_revenue);
tv_total_expenditure = (TextView)view.findViewById(R.id.tv_sum_exp);
tv_balance = (TextView)view.findViewById(R.id.tv_balance);
}
@Override
public void onSaveInstanceState(Bundle outState) {
outState.putString("revenue", String.valueOf(balance));
outState.putString("totalExpenditure", String.valueOf(balance));
outState.putString("balance", String.valueOf(balance));
super.onSaveInstanceState(outState);
}
public void setController(Controller controller) {
this.controller = controller;
}
}
我从我的课监守我因子评分，他们不适合此问题，取消了所有的头文件和一些方法。
以下是错误日志：
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1434)
at android.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1452)
at android.app.BackStackRecord.commitInternal(BackStackRecord.java:708)
at android.app.BackStackRecord.commit(BackStackRecord.java:672)
at com.example.user.my_app.LoggedInActivity.setFragment(LoggedInActivity.java:85)
at com.example.user.my_app.Controller.replaceFragmentWith(Controller.java:89)
at com.example.user.my_app.Controller.setFragmentIncome(Controller.java:99)
at com.example.user.my_app.LoggedInActivity$MyNavigationItemListener.onNavigationItemSelected(LoggedInActivity.java:127)
at android.support.design.widget.NavigationView$1.onMenuItemSelected(NavigationView.java:156)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:156)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:969)
at android.support.design.internal.NavigationMenuPresenter$1.onClick(NavigationMenuPresenter.java:342)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
答
这看起来像一个活动状态的损失。请参阅Alex Lockwood的优秀文章，标题为"Fragment Transactions & Activity State Loss"。我一遍又一遍地提到它。
引述介绍到发帖：
因为蜂窝的初始版本有史以来以下堆栈跟踪和异常消息困扰的StackOverflow：
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1341)
at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1352)
at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:574)
这篇文章将解释为什么并且当抛出这个异常时，最后会有几条建议，这将有助于确保它不会再次崩溃您的应用程序。
尝试使用'getSupportFragmentManager（）'而不是'getFragmentManager（）'因为您使用'AppCompatActivity' – ono
没有帮助，谢谢你的答案。我发现奇怪的是，当我将commit（）更改为commitAllowingStateLoss（）时，代码给了我以下错误“IllegalStateException：Activity已被销毁”。但是，如果它已经在onCreate方法中创建，它怎么会被销毁呢？ – Pakash