onbackpressed按钮上的代码崩溃了。不经常发生，但它是一些空指针活动。代码如下：
public class MainActivity extends AbsBaseActivity implements OnBackStackChangedListener {
public static final int REQUEST_CODE_LIST = 100;
private boolean mIsNavigationOpen = false;
private boolean mIsSearchBarActive;
public boolean isNavigationOpen() {
return mIsNavigationOpen;
}
@SuppressWarnings("deprecation")
public void setNavigationOpen(final boolean isNavigationOpen) {
this.mIsNavigationOpen = isNavigationOpen;
final ImageButton mainButton = (ImageButton) findViewById(R.id.button_main);
if(isNavigationOpen) {
mainButton.setBackgroundResource(R.drawable.bg_helios_active);
} else {
mainButton.setBackgroundDrawable(null);
}
}
private final BroadcastReceiver mMainActivityReceiver = new BroadcastReceiver() {
@Override
public void onReceive(final Context context, final Intent intent) {
final String action = intent.getAction();
if (BroadcastActions.LIST_DELETE_ACTION.equals(action)) {
if (mActiveFragment instanceof ListsFragment || mActiveFragment instanceof ListDetailsFragment) {
final Bundle bundle = intent.getExtras();
final String toastMessage = bundle.getString(DeleteListOperation.TOAST);
final boolean isSuccess = bundle.getBoolean(DeleteListOperation.IS_SUCCESS);
final Toast toast = Toast.makeText(getApplicationContext(), toastMessage, Toast.LENGTH_SHORT);
toast.setGravity(Gravity.CENTER, 0, 0);
toast.show();
if (isSuccess) {
if (mActiveFragment instanceof ListsFragment) {
final ListsFragment fragment = (ListsFragment) mActiveFragment;
fragment.onUpdate();
}
}
}
}
}
};
public static void newInstance(final Activity activity) {
final Intent intent = new Intent(activity, MainActivity.class);
activity.startActivity(intent);
}
@Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
initiateMainActionBar();
final FragmentManager supportFragmentManager = getSupportFragmentManager();
supportFragmentManager.addOnBackStackChangedListener(this);
if (savedInstanceState == null) {
mActiveFragment = DashboardFragment.getInstanceWithTransition(supportFragmentManager);
BangoHelper.onStartSession(this);
} else {
resetToDashboard(supportFragmentManager);
}
BangoHelper.eventDashboard();
}
private void resetToDashboard(final FragmentManager supportFragmentManager) {
FragmentStackManager.getInstance().clearBackStack(supportFragmentManager);
mActiveFragment = DashboardFragment.getInstanceWithNoTransition(supportFragmentManager);
}
private void initiateMainActionBar() {
final ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayShowCustomEnabled(true);
actionBar.setCustomView(R.layout.actionbar_main);
setupOnClickListenerForSearchButton(this);
setupOnClickListenerForMainButton();
setupOnClickListenerForSearchCancelButton(this);
setupOnClickListenerForSearchClearButton(this);
}
private void setupOnClickListenerForSearchCancelButton(final MainActivity activity) {
final Button cancelButton = (Button) findViewById(R.id.button_search_cancel);
cancelButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(final View v) {
final View actionBarView = findViewById(R.id.action_bar_container);
mIsSearchBarActive = MenuUtils.changeActionBar(activity, actionBarView);
}
});
}
private void setupOnClickListenerForSearchClearButton(final Activity activity) {
final ImageButton cancelButton = (ImageButton) findViewById(R.id.clear_search_textbox);
cancelButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(final View view) {
MenuUtils.clearSearchBar(activity);
}
});
}
private void setupOnClickListenerForMainButton() {
final ImageButton mainButton = (ImageButton) findViewById(R.id.button_main);
mainButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(final View v) {
toggleNavigationPanel();
}
});
}
private void setupOnClickListenerForSearchButton(final MainActivity activity) {
final ImageButton searchButton = (ImageButton) findViewById(R.id.search_button);
searchButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(final View v) {
final View searchBarView = findViewById(R.id.search_bar_container);
mIsSearchBarActive = MenuUtils.changeActionBar(activity, searchBarView);
BangoHelper.eventSearch();
}
});
}
@Override
public void manageActionBar() {
setTitle(null);
getSupportActionBar().setDisplayShowHomeEnabled(false);
}
@Override
public boolean onMenuItemSelected(final int featureId, final MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
toggleNavigationPanel();
break;
default:
break;
}
return super.onMenuItemSelected(featureId, item);
}
@Override
protected void onResume() {
final IntentFilter filter = new IntentFilter();
filter.addAction(BroadcastActions.USER_PROFILE);
filter.addAction(BroadcastActions.NEWS_IMAGE);
filter.addAction(BroadcastActions.NEWS_HEADLINES);
registerReceiver(mMainActivityReceiver, filter);
BangoAgent.onResume();
super.onResume();
}
@Override
protected void onPause() {
unregisterReceiver(mMainActivityReceiver);
super.onPause();
BangoAgent.onIdle();
saveTextSize();
}
private void saveTextSize() {
final ContentResolver resolver = Application.getAppContext().getContentResolver();
final ContentValues contentValues = new ContentValues();
contentValues.put(GenericColumns.TEXT_SIZE, SharedPreferencesManager.getInstance().getTextSize().ordinal());
SqlArguments argument = SqlArgumentsFactory.generateUserProfileUpdateSqlArguments();
String where = argument.getWhereClause();
String[] whereArgs = argument.getWhereArgs();
resolver.update(UserProfileContentProvider.USER_PROFILE_URI, contentValues, where, whereArgs);
}
public void pushNewsArticlePagerFragment(final int position, final String selectedCategoryCode, final boolean isMyNews) {
NewsArticlePagerFragment.newInstance(getSupportFragmentManager(), position, selectedCategoryCode, isMyNews);
}
public void onDashboardClicked(final View view) {
toggleNavigationPanel();
if (isFragmentVisible(DashboardFragment.TAG_DASHBOARD_FRAGMENT)) {
return;
}
final FragmentManager manager = getSupportFragmentManager();
final FragmentTransaction transaction = manager.beginTransaction();
transaction.setCustomAnimations(R.anim.slide_in_from_right, R.anim.slide_out_to_left);
FragmentStackManager.getInstance().clearBackStack(getSupportFragmentManager());
mActiveFragment = DashboardFragment.getInstance();
transaction.hide(mActiveFragment);
transaction.show(mActiveFragment);
transaction.commitAllowingStateLoss();
updateActionBarTitle();
}
public void onNewsClicked(final View view) {
if(mIsNavigationOpen) {
toggleNavigationPanel();
}
if (isFragmentVisible(NewsFragment.TAG_NEWS_FRAGMENT)) {
return;
}
FragmentStackManager.getInstance().clearBackStack(getSupportFragmentManager());
mActiveFragment = NewsFragment.newInstance(getSupportFragmentManager());
updateActionBarTitle();
}
public void onMarketClicked(final View view) {
if(mIsNavigationOpen) {
toggleNavigationPanel();
}
if (isFragmentVisible(MarketsFragment.TAG_MARKETS_FRAGMENT)) {
return;
}
FragmentStackManager.getInstance().clearBackStack(getSupportFragmentManager());
mActiveFragment = MarketsFragment.newInstance(getSupportFragmentManager());
updateActionBarTitle();
}
public void onListsClicked(final View view) {
if(mIsNavigationOpen) {
toggleNavigationPanel();
}
if (isFragmentVisible(ListsContainerFragment.TAG_LIST_CONTAINER_FRAGMENT)) {
return;
}
FragmentStackManager.getInstance().clearBackStack(getSupportFragmentManager());
mActiveFragment = ListsContainerFragment.newInstance(getSupportFragmentManager());
updateActionBarTitle();
}
public void onBriefcaseClicked(final View view) {
if(mIsNavigationOpen) {
toggleNavigationPanel();
}
if (isFragmentVisible(BriefcaseFragment.TAG_BRIEFCASE_FRAGMENT)) {
return;
}
FragmentStackManager.getInstance().clearBackStack(getSupportFragmentManager());
mActiveFragment = BriefcaseFragment.newInstance(getSupportFragmentManager());
updateActionBarTitle();
}
private void toggleNavigationPanel() {
final FragmentStackManager manager = FragmentStackManager.getInstance();
if (mIsNavigationOpen) {
NavigationPanelFragment.removeInstance(getSupportFragmentManager());
updateActionBarTitle();
BangoHelper.eventMainNav();
} else {
final TextView title = (TextView) findViewById(R.id.main_title);
title.setText(getString(R.string.title_applications));
NavigationPanelFragment.newInstance(getSupportFragmentManager(), manager.getTopTitle());
}
setNavigationOpen(!mIsNavigationOpen);
}
public void updateActionBarTitle() {
final String title = FragmentStackManager.getInstance().getTopTitle();
final TextView titleView = (TextView) findViewById(R.id.main_title);
titleView.setText(title);
}
private boolean isFragmentVisible(final String tag) {
Fragment fragment = FragmentStackManager.getInstance().getTopFragment();
return fragment != null && tag.equals(fragment.getTag());
}
// TODO: refactor as need (e.g. make an Arraylist)
public interface BackPressListener<T extends Fragment> {
public boolean backPressed(MainActivity fragmentActivity);
}
private BackPressListener<Fragment> backPressListener = null;
public void setBackPressListener (final BackPressListener<Fragment> backPressListener) {
this.backPressListener = backPressListener;
}
@Override
public void onBackPressed() {
BangoHelper.eventBack();
if (backPressListener != null) {
boolean b = false;
// Making sure we trigger the backPressed event if the listener is the top fragment
String bplTag = ((Fragment)backPressListener).getTag();
Fragment topFragment = FragmentStackManager.getInstance().getTopFragment();
if (topFragment != null) {
String topFragemtnTag = topFragment.getTag();
if (bplTag != null && topFragemtnTag != null && bplTag.equals(topFragemtnTag)) {
b = backPressListener.backPressed(this);
}
}
if (b)
return;
backPressListener = null;
}
if (mIsSearchBarActive) {
MenuUtils.hideSearchView(this);
mIsSearchBarActive = false;
} else if (mIsNavigationOpen) {
toggleNavigationPanel();
} else if (!FragmentStackManager.getInstance().popTopFragment()) {
Intent setIntent = new Intent(Intent.ACTION_MAIN);
setIntent.addCategory(Intent.CATEGORY_HOME);
setIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(setIntent);
} else {
Fragment topFragment = FragmentStackManager.getInstance().getTopFragment();
if (topFragment == null) {
mActiveFragment = DashboardFragment.getInstance();
((DashboardFragment)mActiveFragment).refreshDashboard();
} else if (topFragment instanceof AbsArticlePagerFragment) {
((AbsArticlePagerFragment) topFragment).forceUpdateTextSize();
} else if (topFragment instanceof AbsBaseArticleFragment) {
((AbsBaseArticleFragment) topFragment).forceUpdateTextSize();
}
}
updateActionBarTitle();
}
public void onDestroy()
{
if (this.isFinishing())
{
BangoHelper.onEndSession(this);
}
super.onDestroy();
}
public void setActiveFragment(final Fragment fragment) {
mActiveFragment = fragment;
}
public void setIsSearchBarActive(final boolean isSearchBarActive){
mIsSearchBarActive = isSearchBarActive;
}
@Override
public void onBackStackChanged() {
Log.d("BackStack", "=================================================");
for (int i = 0; i < getSupportFragmentManager().getBackStackEntryCount(); i++) {
final BackStackEntry bse = getSupportFragmentManager().getBackStackEntryAt(i);
Log.d("BackStack", "Changed: " + bse.getName());
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE_LIST) {
if (resultCode == RESULT_OK) {
Fragment fragment = FragmentStackManager.getInstance().getTopFragment();
if (fragment == null) { // Implies DashboardFragment because dashboard was never added to backstack
DashboardFragment.getInstance().onUpdate();
} else if (fragment instanceof ListsContainerFragment) {
((ListsContainerFragment) fragment).onUpdate();
} else if (fragment instanceof ListDetailsFragment) {
((ListDetailsFragment) fragment).onUpdate();
}
}
}
}
@Override
public void refreshScreen() {
Fragment fragment = FragmentStackManager.getInstance().getTopFragment();
if (fragment == null) { // Implies DashboardFragment
DashboardFragment.getInstance().refreshScreen();
} else if (fragment instanceof ListsContainerFragment) {
((ListsContainerFragment) fragment).refreshScreen();
} else if (fragment instanceof ListDetailsFragment) {
((ListDetailsFragment) fragment).refreshScreen();
} else if (fragment instanceof MarketsFragment) {
((MarketsFragment) fragment).refreshScreen();
}
}
}
有任何线索吗？谢谢！
logcat的：
MainActivity.onBackPressed
3 android.app.Activity.onKeyUp Activity.java, line 2194
4 android.view.KeyEvent.dispatch KeyEvent.java, line 2782
5 android.app.Activity.dispatchKeyEvent Activity.java, line 2428
6 com.actionbarsherlock.app.SherlockFragmentActivity.dispatchKeyEvent
7 com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent PhoneWindow.java, line 2076
8 android.view.ViewRootImpl.deliverKeyEventPostIme ViewRootImpl.java, line 4196
9 android.view.ViewRootImpl.handleImeFinishedEvent ViewRootImpl.java, line 4125
10 android.view.ViewRootImpl$ViewRootHandler.handleMessage ViewRootImpl.java, line 3173
11 android.os.Handler.dispatchMessage Handler.java, line 99
12 android.os.Looper.loop Looper.java, line 137
13 android.app.ActivityThread.main ActivityThread.java, line 5328
14 java.lang.reflect.Method.invokeNative
15 java.lang.reflect.Method.invoke Method.java, line 511
16 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run ZygoteInit.java, line 1102
17 com.android.internal.os.ZygoteInit.main ZygoteInit.java, line 869
18 dalvik.system.NativeStart.main
答案 0 :(得分：2)
public void onDestroy()
{
if (this.isFinishing())
{
BangoHelper.onEndSession(this);
}
super.onDestroy();
}
我想在这里你需要调用super.onDestroy（）;在if条件之前如下：
public void onDestroy()
{
super.onDestroy();
if (this.isFinishing())
{
BangoHelper.onEndSession(this);
}
}
super.onDestroy（）必须是onDestroy方法的第一次调用，如果你覆盖它。
P.S。我发现了与您类似的问题，但是这里有JakeWharton / ActionBarSherlock问题列表中的菜单键。它有一个NULL检查问题。