Bundle
要发送到onCreate
对于Activity
和Fragment
是完全不同的。如果您将null
发送到super.onCreate
- >活动将从头开始重新创建所有fragments
。所以你的Fragment
将收到null
- >也。因为这是新fragment
这是的FragmentActivity
代码的一部分:
/**
* Perform initialization of all fragments and loaders.
*/
@SuppressWarnings("deprecation")
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
mFragments.attachHost(null /*parent*/);
super.onCreate(savedInstanceState);
NonConfigurationInstances nc =
(NonConfigurationInstances) getLastNonConfigurationInstance();
if (nc != null) {
mFragments.restoreLoaderNonConfig(nc.loaders);
}
if (savedInstanceState != null) {
Parcelable p = savedInstanceState.getParcelable(FRAGMENTS_TAG);
mFragments.restoreAllState(p, nc != null ? nc.fragments : null);
// Check if there are any pending onActivityResult calls to descendent Fragments.
if (savedInstanceState.containsKey(NEXT_CANDIDATE_REQUEST_INDEX_TAG)) {
mNextCandidateRequestIndex =
savedInstanceState.getInt(NEXT_CANDIDATE_REQUEST_INDEX_TAG);
int[] requestCodes = savedInstanceState.getIntArray(ALLOCATED_REQUEST_INDICIES_TAG);
String[] fragmentWhos = savedInstanceState.getStringArray(REQUEST_FRAGMENT_WHO_TAG);
if (requestCodes == null || fragmentWhos == null ||
requestCodes.length != fragmentWhos.length) {
Log.w(TAG, "Invalid requestCode mapping in savedInstanceState.");
} else {
mPendingFragmentActivityResults = new SparseArrayCompat<>(requestCodes.length);
for (int i = 0; i < requestCodes.length; i++) {
mPendingFragmentActivityResults.put(requestCodes[i], fragmentWhos[i]);
}
}
}
}
if (mPendingFragmentActivityResults == null) {
mPendingFragmentActivityResults = new SparseArrayCompat<>();
mNextCandidateRequestIndex = 0;
}
mFragments.dispatchCreate();
}
它们是完全不同的。 – xAqweRx
@xAqweRx然后当我将'null'传递给'Activity'的'super.onCreate'时,传递给'Fragment'的'Bundle'也是'null'。为什么这样? – q126y
将代码粘贴到此处。 – xAqweRx