这很奇怪，但似乎当我将 AnimatorListener 附加到用于动画片段事务的 ObjectAnimator 时，回调实际上会在动画完成之前稍微调用。 我使用侦听器将内容填充到片段中（来自数据库）。该操作有时可能需要相当长的时间（~200ms），当我在 onCreate 左右执行此操作时，它只会破坏动画，因为内容是在动画期间返回并渲染的......然后有很多垃圾和口吃。 。 因此，当我将填充调用添加到侦听器中时，当数据库选择也需要很长时间时它就会起作用。但有时它几乎是瞬时的，在这种情况下，当在动画结束之前调用回调时，我会遇到问题。回调和实际结束之间的间隙足够长，足以从数据库返回数据并再次破坏动画的流畅性：/
你们知道如何解决这个问题吗？下面是该片段的几乎完整代码。
所以基本上有两种方法可以解决这个问题。我可以找到完全另一种解决方案，如何将内容填充到片段中而没有垃圾动画，或者我可以找到一种方法来解决侦听器的问题。
还有一种我不喜欢的额外方式。我可以创建一个处理程序并调用 postDelayed.. 糟糕的解决方案:)
public class ImportantContactsFragment extends Fragment {
public static final String TAG = ImportantContactsFragment.class.getSimpleName();
private ListView list;
private Spinner departmentsSwitcher;
private Spinner facultiesSwitcher;
private ContactsAdapter adapter;
private ArrayList<ImportantContact> currentListOfPeople;
private int currentFaculty = 1;
private Department currentDeparment = Department.STUDY_DEPARTMENT;
private PullToRefreshAttacher mPullToRefreshAttacher;
private boolean boot = true;
private AsyncTask<Integer, ArrayList<ImportantContact>, ArrayList<ImportantContact>> task;
private ArrayList<Faculty> faculties;
private SpinnerAdapter departmentsSpinnerAdapter;
private SpinnerAdapter facultiesSpinnerAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
currentListOfPeople = new ArrayList<ImportantContact>();
faculties = new ArrayList<Faculty>(2);
currentDeparment = Department.STUDY_DEPARTMENT;
faculties.add(Faculty.getFEL());
faculties.add(Faculty.getFIT());
FrameLayout view = (FrameLayout) inflater.inflate(R.layout.important_contacts_fragment_list_layout, container, false);
departmentsSwitcher = (Spinner) view.findViewById(R.id.departmentsSpinner);
facultiesSwitcher = (Spinner) view.findViewById(R.id.facultiesSpinner);
facultiesSpinnerAdapter = new ArrayAdapter<Faculty>(getActivity(), R.layout.spinner_text_view, faculties);
departmentsSpinnerAdapter = new ArrayAdapter<Department>(getActivity(), R.layout.spinner_text_view, Department.values());
departmentsSwitcher.setAdapter(departmentsSpinnerAdapter);
facultiesSwitcher.setAdapter(facultiesSpinnerAdapter);
list = (ListView) view.findViewById(R.id.list);
adapter = new ContactsAdapter(getActivity(), R.layout.important_contacts_list_item, currentListOfPeople, list);
list.setAdapter(adapter);
list.requestFocus();
departmentsSwitcher.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
currentDeparment = (Department) departmentsSpinnerAdapter.getItem(position);
fillAdapterWithData(currentFaculty, currentDeparment);
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
facultiesSwitcher.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
currentFaculty = position + 1;
fillAdapterWithData(currentFaculty, currentDeparment);
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
return view;
}
@Override
public void onResume() {
super.onResume();
Tracking.onResume(this);
// fillAdapterWithData(currentFaculty, currentDeparment);
}
@Override
public void onPause() {
super.onPause();
if (task != null) {
task.cancel(true);
}
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getActivity().getActionBar().setTitle(getString(R.string.important_contacts));
}
public void fillAdapterWithData(int facultyId, Department department) {
if (boot) {
boot = false;
return;
}
currentListOfPeople.clear();
if (task != null) {
task.cancel(true);
}
task = new AsyncTask<Integer, ArrayList<ImportantContact>, ArrayList<ImportantContact>>() {
@Override
protected ArrayList<ImportantContact> doInBackground(Integer... params) {
return Controller.peopleDBController.getListOfImportantContactFromListOfContact(Controller.contactsDBController.searchRows(params[0], params[1]));
}
@Override
protected void onPostExecute(ArrayList<ImportantContact> importantContacts) {
// adapter.notifyDataSetChanged();
adapter.addAll(importantContacts);
}
};
// getActivity().setProgressBarVisibility(true);
task.execute(facultyId, department.ordinal());
adapter.addAll(Controller.peopleDBController.getListOfImportantContactFromListOfContact(Controller.contactsDBController.searchRows(facultyId, department.ordinal())));
}
@Override
public Animator onCreateAnimator(int transit, boolean enter, int nextAnim) {
if(enter){
Animator animator = AnimatorInflater.loadAnimator(getActivity(), R.anim.fragment_slide_anim);
if(animator!=null){
animator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
}
@Override
public void onAnimationEnd(Animator animation) {
// fillAdapterWithData(currentFaculty, currentDeparment);
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
}
return animator;
}
else{
return super.onCreateAnimator(transit, enter, nextAnim);
}
}
有几种方法可以处理这个计时问题，让动画回调稍微提前完成：
您可以使用 Handler 来延迟加载数据，延迟时间非常小，例如 50-100 毫秒。这将确保动画完全完成：
animator.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
Handler().postDelayed(() -> {
// load data
}, 100);
}
});
Animator 类有一个 end() 回调，用于传递动画的实际结束时间。您可以使用它代替侦听器来加载数据：
animator.end(() -> {
// load data
});
使动画稍微长一些，以考虑到早期发生的回调。例如，如果提前 50ms 结束，则将持续时间延长 50ms。
使用View.post()加载动画后下一帧的数据：
animator.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
view.post(() -> {
// load data
});
}
});
总的来说，最简单的选项可能是使用小的延迟或 end() 回调。