StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>Hope somebody finds a better solution. I'll wait for one before I accept my solution:</p> <p>In general, I use generated tags to find the <strong>unhidden</strong> fragments and hide them.</p> <p>In details, I generate a unique tag for each fragment (StackEntry) and stack the tags as the fragments themselves get stacked. I persist the stack in the bundel and load it when the app gets restored in order to continure using it. Then I use the list of tags to find all of the <strong>unhidden</strong> fragments and hide them - except for the last one.</p> <p>Heres sample code:</p> <pre><code>public class FragmentActivity extends Activity { private static final String FRAGMENT_STACK_KEY = "FRAGMENT_STACK_KEY"; private Stack<StackEntry> fragmentsStack = new Stack<StackEntry>(); public FragmentActivity() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.content_frame); if (savedInstanceState == null) { // Init for the first time - not restore // ... } else { Serializable serializable = savedInstanceState.getSerializable(FRAGMENT_STACK_KEY); if (serializable != null) { // Workaround Android bug. // See: http://stackoverflow.com/questions/13982192/when-using-an-android-bundle-why-does-a-serialised-stack-deserialise-as-an-arra // And: https://code.google.com/p/android/issues/detail?id=3847 @SuppressWarnings("unchecked") List<StackEntry> arrayList = (List<StackEntry>) serializable; fragmentsStack = new Stack<StackEntry>(); fragmentsStack.addAll(arrayList); } // Hide all the restored fragments instead of the last one if (fragmentsStack.size() > 1) { FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction(); for (int i = 0; i < fragmentsStack.size()-1; i++) { String fragTag = fragmentsStack.get(i).getFragTag(); Fragment fragment = getFragmentManager().findFragmentByTag(fragTag); fragmentTransaction.hide(fragment); } fragmentTransaction.commit(); } } getFragmentManager().addOnBackStackChangedListener(new OnBackStackChangedListener() { @Override public void onBackStackChanged() { Fragment lastFragment = getLastFragment(); if (lastFragment.isHidden()) { FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction(); fragmentTransaction.show(lastFragment); fragmentTransaction.commit(); } } }); } private Fragment getLastFragment() { if (fragmentsStack.isEmpty()) return null; String fragTag = fragmentsStack.peek().getFragTag(); Fragment fragment = getFragmentManager().findFragmentByTag(fragTag); return fragment; } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putSerializable(FRAGMENT_STACK_KEY, fragmentsStack); } @Override public void onBackPressed() { if (!fragmentsStack.isEmpty()) { fragmentsStack.pop(); } } public void switchContent(Fragment fragment) { FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction(); Fragment lastFragment = getLastFragment(); if (lastFragment != null) { fragmentTransaction.hide(lastFragment); } String fragTag; if (fragment.isAdded()) { fragmentTransaction.show(fragment); fragTag = fragment.getTag(); } else { fragTag = Long.toString(System.currentTimeMillis()); fragmentTransaction.add(R.id.content_frame, fragment, fragTag); } if (!isFirstFragment()) { // Add to backstack only the first content fragment and not the state before (that has nothing) fragmentTransaction.addToBackStack(null); } fragmentTransaction.commit(); fragmentsStack.push(new StackEntry(fragTag)); } public boolean isFirstFragment() { return fragmentsStack.size() == 0; } private static class StackEntry implements Serializable { private static final long serialVersionUID = -6162805540320628024L; private String fragTag = null; public StackEntry(String fragTag) { super(); this.fragTag = fragTag; } public String getFragTag() { return fragTag; } } public static class Intent extends android.content.Intent { public Intent(Context packageContext) { super(packageContext, FragmentActivity.class); } } } </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload