在显示对话框我得到“不能执行此操作后onSaveInstanceState”
有些用户正在报告，如果他们使用通知栏中的快速操作，他们正在接近力量。
我在调用“TestDialog”类的通知中显示一个快速操作。 在按下“snooze”button后的TestDialog类中，我将显示SnoozeDialog。
private View.OnClickListener btnSnoozeOnClick() { return new View.OnClickListener() { public void onClick(View v) { showSnoozeDialog(); } }; } private void showSnoozeDialog() { FragmentManager fm = getSupportFragmentManager(); SnoozeDialog snoozeDialog = new SnoozeDialog(); snoozeDialog.show(fm, "snooze_dialog"); } 错误是IllegalStateException：在onSaveInstanceState后无法执行此操作 。
IllegarStateException被触发的代码行是：
snoozeDialog.show(fm, "snooze_dialog");
该类扩展“FragmentActivity”，“SnoozeDialog”类扩展“DialogFragment”。
以下是错误的完整堆栈跟踪：
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1327) at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1338) at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595) at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:574) at android.support.v4.app.DialogFragment.show(DialogFragment.java:127) at com.test.testing.TestDialog.f(TestDialog.java:538) at com.test.testing.TestDialog.e(TestDialog.java:524) at com.test.testing.TestDialog.d(TestDialog.java:519) at com.test.testing.g.onClick(TestDialog.java:648) at android.view.View.performClick(View.java:3620) at android.view.View$PerformClick.run(View.java:14292) at android.os.Handler.handleCallback(Handler.java:605) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4507) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557) at dalvik.system.NativeStart.main(Native Method)
我无法重现这个错误，但是我收到了很多错误报告。
任何人都可以帮助我如何解决这个错误？
这是常见的问题 。 我们通过重写show（）和处理DialogFragment扩展类中的exception来解决这个问题
public class CustomDialogFragment extends DialogFragment { @Override public void show(FragmentManager manager, String tag) { try { FragmentTransaction ft = manager.beginTransaction(); ft.add(this, tag); ft.commit(); } catch (IllegalStateException e) { Log.d("ABSDIALOGFRAG", "Exception", e); } }
}
这意味着你在onSaveInstanceState()之后commit() （ show()在DialogFragment的情况下）片段。
Android会保存你的片段状态在onSaveInstanceState() 。 所以，如果你在onSaveInstanceState()片段状态丢失后commit()片段。
因此，如果Activity被杀死并且稍后重新创build，那么片段将不会添加到不良用户体验的活动中。 这就是为什么Android不会不惜一切代价让国家损失的原因。
简单的解决scheme是检查状态是否已经保存。
boolean mIsStateAlreadySaved = false; boolean mPendingShowDialog = false; @Override public void onResumeFragments(){ super.onResumeFragments(); mIsStateAlreadySaved = false; if(mPendingShowDialog){ mPendingShowDialog = false; showSnoozeDialog(); } } @Override public void onPause() { super.onPause(); mIsStateAlreadySaved = true; } private void showSnoozeDialog() { if(mIsStateAlreadySaved){ mPendingShowDialog = true; }else{ FragmentManager fm = getSupportFragmentManager(); SnoozeDialog snoozeDialog = new SnoozeDialog(); snoozeDialog.show(fm, "snooze_dialog"); } }
注意：onResumeFragments（）将在分段恢复时调用。
如果对话框不是非常重要（当应用程序closures/不再显示时没有显示它），请使用：
boolean running = false; @Override public void onStart() { running = true; super.onStart(); } @Override public void onStop() { running = false; super.onStop(); }
只有在运行时才打开对话框（片段）：
if (running) { yourDialog.show(...); }
编辑，可能更好的解决scheme：
在生命周期中调用onSaveInstanceState的地方是不可预知的，我认为更好的解决scheme是检查isSavedInstanceStateDone（）是这样的：
/** * True if SavedInstanceState was done, and activity was not restarted or resumed yet. */ private boolean savedInstanceStateDone; @Override protected void onResume() { super.onResume(); savedInstanceStateDone = false; } @Override protected void onStart() { super.onStart(); savedInstanceStateDone = false; } protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); savedInstanceStateDone = true; } /** * Returns true if SavedInstanceState was done, and activity was not restarted or resumed yet. */ public boolean isSavedInstanceStateDone() { return savedInstanceStateDone; }
请尝试使用FragmentTransaction而不是FragmentManager。 我认为下面的代码将解决您的问题。 如果没有，请让我知道。
FragmentTransaction ft = getSupportFragmentManager().beginTransaction(); SnoozeDialog snoozeDialog = new SnoozeDialog(); snoozeDialog.show(ft, "snooze_dialog");
编辑：
片段交易
请检查这个链接。 我想这会解决你的疑问。
private void showSnoozeDialog() { FragmentManager fm = getSupportFragmentManager(); SnoozeDialog snoozeDialog = new SnoozeDialog(); // snoozeDialog.show(fm, "snooze_dialog"); FragmentTransaction ft = getSupportFragmentManager().beginTransaction(); ft.add(dialog, null); ft.commitAllowingStateLoss(); }
ref： 链接
几天后，我想分享我的解决scheme，我已经修复了它，显示DialogFragment，你应该重写它的show()方法，并在Transaction对象上调用commitAllowingStateLoss() 。 这里是Kotlin的例子：
override fun show(manager: FragmentManager?, tag: String?) { try { val ft = manager?.beginTransaction() ft?.add(this, tag) ft?.commitAllowingStateLoss() } catch (ignored: IllegalStateException) { } }
虽然没有任何地方正式提到，但我偶然遇到过这个问题。 根据我的经验，在旧版平台上支持片段的兼容性库会导致这个问题。 您可以使用普通的片段pipe理器API来使用testing。 如果没有任何作品，那么你可以使用普通的对话框而不是对话框片段
以下实现可以用来解决在Activity生命周期中执行安全状态更改的问题，特别是用于显示对话框的问题：如果实例状态已经被保存（例如，由于configuration更改），则推迟它们直到恢复状态已经执行。
public abstract class XAppCompatActivity extends AppCompatActivity { private String TAG = this.getClass().getSimpleName(); /** The retained fragment for this activity */ private ActivityRetainFragment retainFragment; /** If true the instance state has been saved and we are going to die... */ private boolean instanceStateSaved; @Override protected void onPostCreate(Bundle savedInstanceState) { super.onPostCreate(savedInstanceState); // get hold of retain Fragment we'll be using retainFragment = ActivityRetainFragment.get(this, "Fragment-" + this.getClass().getName()); } @Override protected void onPostResume() { super.onPostResume(); // reset instance saved state instanceStateSaved = false; // execute all the posted tasks for (ActivityTask task : retainFragment.tasks) task.exec(this); retainFragment.tasks.clear(); } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); instanceStateSaved = true; } /** * Checks if the activity state has been already saved. * After that event we are no longer allowed to commit fragment transactions. * @return true if the instance state has been saved */ public boolean isInstanceStateSaved() { return instanceStateSaved; } /** * Posts a task to be executed when the activity state has not yet been saved * @param task The task to be executed * @return true if the task executed immediately, false if it has been queued */ public final boolean post(ActivityTask task) { // execute it immediately if we have not been saved if (!isInstanceStateSaved()) { task.exec(this); return true; } // save it for better times retainFragment.tasks.add(task); return false; } /** Fragment used to retain activity data among re-instantiations */ public static class ActivityRetainFragment extends Fragment { /** * Returns the single instance of this fragment, creating it if necessary * @param activity The Activity performing the request * @param name The name to be given to the Fragment * @return The Fragment */ public static ActivityRetainFragment get(XAppCompatActivity activity, String name) { // find the retained fragment on activity restarts FragmentManager fm = activity.getSupportFragmentManager(); ActivityRetainFragment fragment = (ActivityRetainFragment) fm.findFragmentByTag(name); // create the fragment and data the first time if (fragment == null) { // add the fragment fragment = new ActivityRetainFragment(); fm.beginTransaction().add(fragment, name).commit(); } return fragment; } /** The queued tasks */ private LinkedList<ActivityTask> tasks = new LinkedList<>(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // retain this fragment setRetainInstance(true); } } /** A task which needs to be performed by the activity when it is "fully operational" */ public interface ActivityTask { /** * Executed this task on the specified activity * @param activity The activity */ void exec(XAppCompatActivity activity); } }
然后使用这样的一个类：
/** AppCompatDialogFragment implementing additional compatibility checks */ public abstract class XAppCompatDialogFragment extends AppCompatDialogFragment { /** * Shows this dialog as soon as possible * @param activity The activity to which this dialog belongs to * @param tag The dialog fragment tag * @return true if the dialog has been shown immediately, false if the activity state has been saved * and it is not possible to show it immediately */ public boolean showRequest(XAppCompatActivity activity, final String tag) { return showRequest(activity, tag, null); } /** * Shows this dialog as soon as possible * @param activity The activity to which this dialog belongs to * @param tag The dialog fragment tag * @param args The dialog arguments * @return true if the dialog has been shown immediately, false if the activity state has been saved * and it is not possible to show it immediately */ public boolean showRequest(XAppCompatActivity activity, final String tag, final Bundle args) { return activity.post(new XAppCompatActivity.ActivityTask() { @Override public void exec(XAppCompatActivity activity) { if (args!= null) setArguments(args); show(activity.getSupportFragmentManager(), tag); } }); } /** * Dismiss this dialog as soon as possible * @return true if the dialog has been dismissed immediately, false if the activity state has been saved * and it is not possible to dismissed it immediately */ public boolean dismissRequest() { return dismissRequest(null); } /** * Dismiss this dialog as soon as possible * @param runnable Actions to be performed before dialog dismissal * @return true if the dialog has been dismissed immediately, false if the activity state has been saved * and it is not possible to dismissed it immediately */ public boolean dismissRequest(final Runnable runnable) { // workaround as in rare cases the activity could be null XAppCompatActivity activity = (XAppCompatActivity)getActivity(); if (activity == null) return false; // post the dialog dismissal return activity.post(new XAppCompatActivity.ActivityTask() { @Override public void exec(XAppCompatActivity activity) { if (runnable != null) runnable.run(); dismiss(); } }); } }
您可以放心地显示对话框，而不用担心应用程序状态：
public class TestDialog extends XAppCompatDialogFragment { private final static String TEST_DIALOG = "TEST_DIALOG"; public static void show(XAppCompatActivity activity) { new TestDialog().showRequest(activity, TEST_DIALOG); } public TestDialog() {} @NonNull @Override public Dialog onCreateDialog(Bundle savedInstanceState) { return new AlertDialog.Builder(getActivity(), R.style.DialogFragmentTheme /* or null as you prefer */) .setTitle(R.string.title) // set all the other parameters you need, eg Message, Icon, etc. ).create(); } }
然后从TestDialog.show(this)调用TestDialog.show(this) 。
如果要使用参数创build更通用的对话框类，可以使用show()方法将它们保存在Bundle ，并使用onCreateDialog() getArguments()方法检索它们。
整个方法看起来有点复杂，但是一旦创build了活动和对话框的两个基类，它就很容易使用，并且完美地工作。 它可以用于其他基于Fragment的操作，这可能会受到相同问题的影响。
- 将这个类添加到你的项目中:(必须在android.support.v4.app包中）
包android.support.v4.app;
/ **
*由Gil在8/16/2017创build。
* /
公共类StatelessDialogFragment扩展DialogFragment {
/ **
*显示对话框，使用现有的事务添加片段，然后提交
*交易，同时允许国家损失。
*
*我build议大部分时间使用{@link #show（FragmentTransaction，String）}
*这是你真正不关心的对话。 （debugging/跟踪/广告等）
*
* @param交易
*添加片段的现有事务。
* @参数标签
*这个片段的标签，按照
* {@link FragmentTransaction＃add（Fragment，String）FragmentTransaction.add}。
* @return按照每个返回已提交事务的标识符
* {@link FragmentTransaction＃commit（）FragmentTransaction.commit（）}。
* @see StatelessDialogFragment＃showAllowingStateLoss（FragmentManager，String）
* /
public int showAllowingStateLoss（FragmentTransaction事务，String标记）
{
mDismissed = false;
mShownByMe = true;
transaction.add（this，tag）;
mViewDestroyed = false;
mBackStackId = transaction.commitAllowingStateLoss（）;
返回mBackStackId;
}
/ **
*显示对话框，将片段添加到给定的FragmentManager。 这是一个方便
*为显式创build一个事务，添加片段给它与给定的标签，和
*承诺它不关心状态。 这不会将交易添加到
*返回堆栈。 当片段被解散时，将执行一个新的事务来移除它
*来自活动。
*
*我build议你在大部分时间使用{@link #show（FragmentManager，String）}，但这是
*对于你真正不关心的对话。 （debugging/跟踪/广告等）
*
*
* @param经理
*片段pipe理器这个片段将被添加到。
* @参数标签
*这个片段的标签，按照
* {@link FragmentTransaction＃add（Fragment，String）FragmentTransaction.add}。
* @see StatelessDialogFragment＃showAllowingStateLoss（FragmentTransaction，String）
* /
公共无效showAllowingStateLoss（FragmentManager经理，string标签）
{
mDismissed = false;
mShownByMe = true;
FragmentTransaction ft = manager.beginTransaction（）;
ft.add（this，tag）;
ft.commitAllowingStateLoss（）;
}
}
- 扩展StatelessDialogFragment而不是DialogFragment
-
使用方法showAllowingStateLoss而不是show
-
请享用 ;）
