标题可能有点令人困惑，所以我希望我能正确表达我的问题。因此，我正在研究一个简单的锻炼日志应用程序。我有片段ActiveWorkout，如图像1所示。当我按下粉色的添加按钮时，我被定向到另一个片段，该片段包含不同的练习，如列表2所示，然后如图2所示。然后，我将选择一个练习（使用onItemClickListener）并且该练习的标题应该发送回ActiveWorkoutFragment并添加到Active Workout，所以它应该类似于图3。所以这里的问题是，我不完全知道如何保持Active Workout处于“活动状态”，如果我想添加另一个练习，并且应该再次更新它，而我再次按下粉红色的添加按钮时不要空白，那么最后它应该类似于图4。我正在考虑使用Bundle发送数据，我也在代码中尝试过，但更困难的部分是在不删除以前添加的练习的情况下更新“锻炼”列表。顺便说一句，我尝试执行此类操作的原因是因为数据实际上位于Firebase数据库中，所以从某种意义上讲，我正尝试从Workout数据库中检索数据。
图像：
[Image 1Image 2Image 3 Image 4
这是练习列表或目录：
public class ExercisesFragment extends Fragment {
private ListView lv;
private FirebaseListAdapter adapter;
private ArrayList<Exercise> exerciseList;
private ArrayList<String> nameList;
//private Adapter adapter;
public ExercisesFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_exercises, container, false);
lv = v.findViewById(R.id.lv);
Query query = FirebaseDatabase.getInstance().getReference().child("exerciseList");
FirebaseListOptions<ExerciseElement> options = new FirebaseListOptions.Builder<ExerciseElement>()
.setLayout(R.layout.exercise)
.setQuery(query, ExerciseElement.class)
.build();
adapter = new FirebaseListAdapter(options) {
@Override
protected void populateView(@NonNull View v, @NonNull Object model, int position) {
TextView bodypart = v.findViewById(R.id.bodypart);
TextView title = v.findViewById(R.id.title);
ExerciseElement el = (ExerciseElement) model;
bodypart.setText(el.getBodypart().toString());
title.setText(el.getTitle().toString());
}
};
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
ExerciseElement el = (ExerciseElement) lv.getItemAtPosition(position);
String item = el.getTitle();
ActiveWorkoutFragment awf = new ActiveWorkoutFragment();
Bundle args = new Bundle();
args.putString("ExerciseTitle", item);
awf.setArguments(args);
getFragmentManager().beginTransaction().replace(R.id.nav_host_fragment, awf).commit();
//Navigation.findNavController(v).navigate(R.id.activeWorkoutFragment);
}
});
return v;
}
@Override
public void onStart() {
super.onStart();
adapter.startListening();
}
@Override
public void onStop() {
super.onStop();
adapter.stopListening();
}
}
然后是ActiveWorkoutFragment，它稍长一些，但上面的部分不是问题。当我单击粉红色的添加按钮时，将调用addNewExercise（）方法，因此我试图以某种方式检索数据。
public class ActiveWorkoutFragment extends Fragment {
private Workout workout;
private TextView emptyRecyclerView;
private RecyclerView exerciseRecyclerView;
private ExerciseRecyclerViewAdapter adapter;
private WorkoutHistory workoutHistory;
private FloatingActionButton fab;
private FirebaseAuth mAuth;
private DatabaseReference databaseWorkouts;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_active_workout, container, false);
fab = v.findViewById(R.id.fab);
fab.setOnClickListener(this::addNewExercise);
setHasOptionsMenu(true);
workout = new Workout("WORKOUT");
if(savedInstanceState != null) {
workout = savedInstanceState.getParcelable("key");
}
emptyRecyclerView = v.findViewById(R.id.empty_recycler_view);
//buildRecyclerView(workout);
exerciseRecyclerView = v.findViewById(R.id.recycler_view_exercise);
// improves performance if size of RecyclerView content is fixed
// taken from developer.android.com
exerciseRecyclerView.setHasFixedSize(true);
// use a linear layout manager for RecyclerView
LinearLayoutManager layoutManager = new LinearLayoutManager(this.getContext());
exerciseRecyclerView.setLayoutManager(layoutManager);
// add divider
RecyclerView.ItemDecoration itemDecoration = new
DividerItemDecoration(this.getContext(), DividerItemDecoration.VERTICAL);
exerciseRecyclerView.addItemDecoration(itemDecoration);
// Create adapter and set its data set to workout
adapter = new ExerciseRecyclerViewAdapter(workout, this);
// Set up swipe to dismiss and ability to move RecyclerView items around
// Create callback object for ItemTouchHelper
ItemTouchHelper.Callback callback = new CustomItemTouchHelperCallback(adapter);
// Implement object created above
ItemTouchHelper touchHelper = new ItemTouchHelper(callback);
touchHelper.attachToRecyclerView(exerciseRecyclerView);
if (adapter.getItemCount() == 0)
{
showEmptyRecyclerViewText();
}
else
{
exerciseRecyclerView.setAdapter(adapter);
}
return v;
}
// Adds save button (check mark) to action bar
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.active_workout_action_bar, menu);
super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_save: {
List<Exercise> exercises = workout.getExercises();
mAuth = FirebaseAuth.getInstance();
String user_id = mAuth.getCurrentUser().getUid();
databaseWorkouts = FirebaseDatabase.getInstance().getReference("Workouts").child(user_id);
String id = databaseWorkouts.push().getKey();
workout = new Workout("abc", user_id, exercises);
databaseWorkouts.child(id).setValue(workout);
Toast.makeText(getContext(), "Workout saved", Toast.LENGTH_SHORT).show();
return true;
}
case R.id.action_delete: {
exerciseRecyclerView.requestFocus();
AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
builder.setTitle("Confirm deletion").setMessage("Are you sure you want to delete" +
" this workout?");
builder.setPositiveButton(android.R.string.yes, (dialog, which) -> {
try {
workoutHistory.removeWorkout(workout);
} catch (IOException e) {
e.printStackTrace();
}
Toast.makeText(getContext(), "Workout deleted", Toast.LENGTH_SHORT).show();
});
builder.setNegativeButton(android.R.string.no, (dialog, which) -> {
dialog.dismiss();
});
builder.show();
return true;
}
default:
// unrecognized button pressed
return super.onOptionsItemSelected(item);
}
}
public void showEmptyRecyclerViewText()
{
emptyRecyclerView.setVisibility(View.VISIBLE);
}
public void addNewExercise(View view) {
Bundle bundle = getArguments();
String value = "";
if(bundle != null) {
value = bundle.getString("ExerciseTitle");
}
System.out.println("lala");
System.out.println(value);
Exercise newExercise = new Exercise(value, -1, -1);
if (exerciseRecyclerView.getAdapter() == null) {
exerciseRecyclerView.setAdapter(adapter);
}
emptyRecyclerView.setVisibility(View.INVISIBLE);
workout.addExercise(newExercise);
adapter.notifyItemInserted(workout.getExercises().size() - 1);
}
private void hideKeyboard(Context context, View view) {
InputMethodManager imm = (InputMethodManager) context.getSystemService
(Activity.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
@Override
public void onSaveInstanceState(@NonNull Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelable("key", workout);
}
}
请以此为基础。给它添加视图和其他必要的方法，但是它将为您提供模块的流程
//contract to update Framgents
public interface FragUpdater {
public void updateExerciseFrag(Exercise exercise);
}
public class ExerciseActiity extends AppCompatActivity implements FragUpdater {
FragmentManager fm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exercise_actiity);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
gotoActiveWorkoutFragment();
}
});
fm = getSupportFragmentManager();
gotoExercisesFragment();
}
private void gotoActiveWorkoutFragment() {
ActiveWorkoutFragment activeWorkoutFragment = new ActiveWorkoutFragment();
Bundle bundle = new Bundle();
activeWorkoutFragment.setArguments(bundle);
fm.beginTransaction().add(R.id.content_frame, activeWorkoutFragment, "ExerciseSelectionFrag").addToBackStack(null).commit();
}
private void gotoExercisesFragment() {
ExercisesFragment exercisesFragment = new ExercisesFragment();
Bundle bundle = new Bundle();
exercisesFragment.setArguments(bundle);
fm.beginTransaction().replace(R.id.content_frame, exercisesFragment, "ExerciseDisplayFrag").commit();
}
@Override
public void updateExerciseFrag(Exercise exercise) {
// Get Fragment ExercisesFragment
ExercisesFragment frag = (ExercisesFragment)
fm.findFragmentByTag("ExerciseDisplayFrag");
if (frag == null) {
return;
}
frag.updateList(exercise);
}
}
public class ExercisesFragment extends Fragment {
//here update your list in ExerciseFragment
public void updateList(Exercise exercise) {}
}
public class ActiveWorkoutFragment extends Fragment {
FragUpdater fragUpdater;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fragUpdater = (ExerciseActiity) getActivity();
}
private void selectListItem(Exercise exercise) {
fragUpdater.updateExerciseFrag(exercise);
getActivity().getSupportFragmentManager().popBackStack();
}
}