Question

我的RecyclerView应该可以显示来自WorkoutSNR和WorkoutCurcuit的对象练习，两者都可以扩展课程Workout。我的RecyclerView看起来像这样：

public class ViewAdapter_ExerciseData extends RecyclerView.Adapter<RecyclerView.ViewHolder>{

private Workout workout;
private Activity activity;

private static final int SNR = 1;
private static final int CURCUIT = 2;

public ViewAdapter_ExerciseData(Workout workout, Activity activity) {
    this.workout = workout;
    this.activity = activity;
}

@Override
public int getItemViewType(int position) {
    if (workout instanceof WorkoutSNR) {
        return SNR;
    }

    if (workout instanceof WorkoutCurcuit) {
        return CURCUIT;
    }
    throw new RuntimeException("error");
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    RecyclerView.ViewHolder viewHolder = null;
    LayoutInflater inflater = LayoutInflater.from(parent.getContext());

    View v1 = inflater.inflate(R.layout.rv_item_data_workout_snr_excersise, parent, false);
    switch (viewType) {
        case SNR:
            viewHolder = new ViewAdapter_ExerciseData.Holder_WorkoutDataSNR(v1);
            break;
        case CURCUIT:
            viewHolder = new ViewAdapter_ExerciseData.Holder_WorkoutDataSNR(v1);
            break;
    }

    return viewHolder;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        ...
    }
}

当我从 Firebase 加载WorkoutSNR时，一切正常。但是，当为WorkoutCurcuit执行相同操作时，不会调用适配器中的getItemViewType。这是我用来加载WorkoutCurcuit并将适配器设置为RecyclerView

的方法

private void buildWorkoutCurcuit() {
    fb.getRefWorkoutCurcuit(workoutKey).addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            final WorkoutCurcuit workoutCurcuit = dataSnapshot.getValue(WorkoutCurcuit.class);
            workoutCurcuit.setKey(dataSnapshot.getKey());

            final ViewAdapter_ExerciseData adapter = new ViewAdapter_ExerciseData(workoutCurcuit, Activity_WorkoutData.this);

            for (int i = 0; i < workoutCurcuit.getExcersiseKeys().size(); i++) {

                fb.getRefExerciseEntriesCurcuit(workoutCurcuit.getExcersiseKeys().get(i)).addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        final ExerciseEntryCurcuit entry = dataSnapshot.getValue(ExerciseEntryCurcuit.class);
                        entry.setKey(dataSnapshot.getKey());

                        fb.getRefUserPresets(entry.getPresetKey()).addListenerForSingleValueEvent(new ValueEventListener() {
                            @Override
                            public void onDataChange(DataSnapshot dataSnapshot) {

                                ExcersisePresets preset = dataSnapshot.getValue(ExcersisePresets.class);
                                preset.setKey(dataSnapshot.getKey());

                                entry.setPreset(preset);
                                workoutCurcuit.addExercsise(entry);

                                rvExcersises.setAdapter(adapter);
                                prg.setVisibility(View.GONE);
                            }

                            @Override
                            public void onCancelled(DatabaseError databaseError) {
                                Toast.makeText(Activity_WorkoutData.this, "Error", Toast.LENGTH_SHORT).show();
                            }
                        });
                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Toast.makeText(Activity_WorkoutData.this, "Error", Toast.LENGTH_SHORT).show();
        }
    });
}

正如我所说，当我为WorkoutSNR执行相同的操作时，这与我用来加载WorkoutCuruit的方法几乎相同，我只使用其他参考，它的工作原理应该如此。 'getItemViewType'被调用，但当我为WorkoutCurcuit执行时，它将不会被调用。

Answer 1

我在你的适配器中没有看到这个方法，如果不在那里就添加它

public int getItemCount() {
    return list.size();
}

Answer 2

好的，我发现了我的错误，我使用了错误的类，在一个地方被称为相同。对不起，我浪费你的时间......

RecyclerView getItemViewType未调用

2 个答案: