我收到了来自 fabric.io 的以下崩溃报告（主要是在我添加了一个可以从我的 SlidingMenue 加载到我的应用程序的 SettingsActivity 之后）：
发布 pendingRunnable 的代码最近没有更改，反正它开始接收异常。
Fatal Exception: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1842)
at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1860)
at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:650)
at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:609)
at my.app.ui.activity.MainActivity$2.run(MainActivity.java:271)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5530)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:733)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:623)
这是我的 MainActivity.java
public class MainActivity extends AppCompatActivity implements MyAppFragment.OnListFragmentInteractionListener, AsyncResponse {
private MyAppDatabaseHandler myAppDatabaseHandler;
private SharedPreferences sharedpreferences;
private SharedPreferences defaultPrefs;
private FragmentA fragmentA;
public static boolean activityVisible = true;
private boolean isAttached;
private NavigationView navigationView;
private DrawerLayout drawer;
private View navHeader;
private Toolbar toolbar;
// index to identify current nav menu item
private static int navItemIndex = 0;
public static String CURRENT_TAG = MyAppConstants.TAG_A;
// toolbar titles respected to selected nav menu item
private String[] activityTitles;
// flag to load home fragment when user presses back key
private boolean shouldLoadHomeFragOnBackPress = true;
private Handler mHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.myAppDatabaseHandler= MyAppDatabaseHandler.getInstance(this);
defaultPrefs = PreferenceManager.getDefaultSharedPreferences(this);
sharedpreferences = getSharedPreferences(MyAppConstants.PREFERENCES, Context.MODE_PRIVATE);
setContentView(R.layout.activity_main);
fragmentA = new FragmentA();
// Init UI
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mHandler = new Handler();
drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
navigationView = (NavigationView) findViewById(R.id.nav_view);
// load toolbar titles from string resources
activityTitles = getResources().getStringArray(R.array.sliding_menu_item_activity_titles);
// load nav menu header data
loadNavHeader();
// initializing navigation menu
setUpNavigationView();
if (savedInstanceState == null) {
navItemIndex = 0;
CURRENT_TAG = MyAppConstants.TAG_A;
loadNextFragment();
}
}
/***
* Load navigation menu header information
* like background image, profile image
* name, website, notifications action view (dot)
*/
private void loadNavHeader() {
// Init NavigationHeader
}
/***
* Returns respected fragment that user
* selected from navigation menu
*/
private void loadNextFragment() {
// if user select the current navigation menu again, don't do anything
// just close the navigation drawer
if (getSupportFragmentManager().findFragmentByTag( CURRENT_TAG) != null && navItemIndex != 4) {
drawer.closeDrawers();
return;
}
if (navItemIndex == 4) {
startActivity(new Intent(MainActivity.this, SettingsActivity.class));
} else {
// set toolbar title
setToolbarTitle();
// Sometimes, when fragment has huge data, screen seems hanging
// when switching between navigation menus
// So using runnable, the fragment is loaded with cross fade effect
// This effect can be seen in GMail app
Runnable mPendingRunnable = new Runnable() {
@Override
public void run() {
// update the activity_main_header_with_item content by replacing fragments
Fragment fragment = getNextFragment();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);
fragmentTransaction.replace(R.id.frame, fragment, CURRENT_TAG);
fragmentTransaction.commit();
}
};
// If mPendingRunnable is not null, then add to the message queue
if (mPendingRunnable != null) {
mHandler.post(mPendingRunnable);
}
}
//Closing drawer on item click
drawer.closeDrawers();
// refresh toolbar menu
invalidateOptionsMenu();
}
private Fragment getNextFragment() {
switch (navItemIndex) {
case 0:
// home
return this.fragmentA;
case 1:
FragmentB fragmentB = new FragmentB();
return fragmentB;
case 2:
// About Fragment
AboutFragment aboutFragment = new AboutFragment();
return aboutFragment;
case 3:
// Licence Fragment
LicenceFragment licenceFragment = new LicenceFragment();
return licenceFragment;
default:
return this.fragmentA;
}
}
private void setToolbarTitle() {
getSupportActionBar().setTitle(activityTitles[navItemIndex]);
}
private void setUpNavigationView() {
//Setting Navigation View Item Selected Listener to handle the item click of the navigation menu
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
// This method will trigger on item Click of navigation menu
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
//Check to see which item was being clicked and perform appropriate action
switch (menuItem.getItemId()) {
//Replacing the activity_main_header_with_item content with ContentFragment Which is our Inbox View;
case R.id.nav_home:
navItemIndex = 0;
CURRENT_TAG = MyAppConstants.TAG_A;
break;
case R.id.nav_recently:
navItemIndex = 1;
CURRENT_TAG = MyAppConstants.TAG_B;
break;
case R.id.nav_about_us:
navItemIndex = 2;
CURRENT_TAG = MyAppConstants.TAG_ABOUT;
break;
case R.id.nav_licences:
navItemIndex = 3;
CURRENT_TAG = MyAppConstants.TAG_LICENCES;
break;
case R.id.nav_settings:
navItemIndex = 4;
// do not set CURRENT_TAG
break;
default:
navItemIndex = 0;
}
loadNextFragment();
return true;
}
});
ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.openDrawer, R.string.closeDrawer) {
@Override
public void onDrawerClosed(View drawerView) {
// Code here will be triggered once the drawer closes as we dont want anything to happen so we leave this blank
super.onDrawerClosed(drawerView);
}
@Override
public void onDrawerOpened(View drawerView) {
// Code here will be triggered once the drawer open as we dont want anything to happen so we leave this blank
super.onDrawerOpened(drawerView);
}
};
//Setting the actionbarToggle to drawer layout
drawer.setDrawerListener(actionBarDrawerToggle);
//calling sync state is necessary or else your hamburger icon wont show up
actionBarDrawerToggle.syncState();
}
@Override
public void onBackPressed() {
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawers();
return;
}
// This code loads home fragment when back key is pressed
// when user is in other fragment than home
if (shouldLoadHomeFragOnBackPress && CURRENT_TAG != MyAppConstants.TAG_A) {
// checking if user is on other navigation menu
// rather than home
if (navItemIndex != 0) {
navItemIndex = 0;
CURRENT_TAG = MyAppConstants.TAG_A;
loadNextFragment();
return;
}
}
finish();
super.onBackPressed();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main_header_with_item, menu);
// Disable Player Icon in case no player is found on device
Intent intent = Intent.makeMainSelectorActivity(Intent.ACTION_MAIN, MyAppConstants.MUSIC_APP);
List<ResolveInfo> activities = getPackageManager().queryIntentActivities(intent, 0);
if(activities == null || activities.size() <= 0) {
MenuItem player = menu.findItem(R.id.player);
if(player != null){
player.setVisible(false);
}
}
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
return super.onOptionsItemSelected(item);
}
public void notifyOnDelete(View v) {
myAppDatabaseHandler.deleteAll();
}
@Override
public void onListFragmentInteraction(Song item) {
}
@Override
public void processFinish(String output) {
if (isAttached) {
...
}
}
@Override
public void onAttachedToWindow() {
isAttached = true;
super.onAttachedToWindow();
}
@Override
public void onDetachedFromWindow() {
isAttached = false;
super.onDetachedFromWindow();
}
@Override
public void onResume() {
activityVisible = true;
updateFragmentA();
super.onResume();
}
@Override
public void onPause() {
activityVisible = false;
super.onPause();
}
@Override
protected void onDestroy() {
super.onDestroy();
}
@Override
protected void onStart() {
super.onStart();
}
public void updateFragmentA() {
if (CURRENT_TAG == MyAppConstants.TAG_A) {
Timber.i( "updating FragmentA");
fragmentA.swap();
}
}
}
关于这个问题的原因有什么想法吗？