我有一个firebase recyclerview，我试图在其中填充firebase数据库中的一些数据。初始页面加载2秒钟后，数据加载非常平稳。最初加载页面时，通常会显示2或3秒的黑屏。在Firebase Recycler视图完成从Firebase数据库中检索数据之后，我尝试在此期间放置一个进度对话框，并关闭了进度对话框。但是进度对话框似乎从来没有出现过。我将在Firebase recyclerview加载完成后立即在onCreate（）方法中初始化进度对话框，并在onResume（）方法中取消进度对话框
我尝试使用进度条代替进度对话框，但是问题仍然与我提到的相同。我还尝试使用android Handler和timer方法为其提供默认计时，但这将是静态方法，不足以解决长期问题
private ProgressDialog loadingBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search_task_list);
// loading bar
loadingBar = new ProgressDialog(this);
loadingBar.setMessage("Please wait...");
loadingBar.setCanceledOnTouchOutside(false);
loadingBar.show();
//Recyclerview and linear layout manager
search_task_list_recycler =
findViewById(R.id.search_task_list_recycler);
linearLayoutManager = new LinearLayoutManager(this);
search_task_list_recycler.setHasFixedSize(true);
linearLayoutManager.setReverseLayout(true);
linearLayoutManager.setStackFromEnd(true);
search_task_list_recycler.setLayoutManager(linearLayoutManager);
}
// ====================================================================
@Override
protected void onResume() {
super.onResume();
// displaytask() contains the firebase recyclerview retrieval method
and recyclerview view
displayTasks();
loadingBar.dismiss();
}
// ====================================================================
private void displayTasks() {
Query query = search_task_list;
FirebaseRecyclerOptions<Search_task_details> options = new
FirebaseRecyclerOptions.Builder<Search_task_details>()
.setQuery(query, Search_task_details.class).build();
final FirebaseRecyclerAdapter<Search_task_details, ViewHolder>
adapter =
new FirebaseRecyclerAdapter<Search_task_details, ViewHolder>
(options) {
@Override
protected void onBindViewHolder(@NonNull final ViewHolder
holder, int position, @NonNull final Search_task_details model) {
UsersRef.child(model.getPoster_id()).addValueEventListener(new
ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot
dataSnapshot) {
if (dataSnapshot.exists()) {
if
(dataSnapshot.hasChild("profile_image")) {
Picasso.get().load(dataSnapshot.child("profile_image").getValue().toString())
.placeholder(R.drawable.submit_profile_image)
.into(holder.search_task_user_image);
}
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
holder.search_task_topic_title.setText(model.getTopic_title());
holder.search_task_due_date.setText(model.getDue_date());
holder.search_task_preferred_timing.setText(model.getPreferred_time());
holder.search_task_location.setText(model.getTask_location());
holder.search_task_job_status.setText(model.getJob_status());
holder.search_task_budget.setText(model.getSum_total() + " B.D");
String givenDateString = model.getCurrent_calendar_Date_and_Time();
SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy, HH:mm", Locale.ENGLISH);
sdf.setTimeZone(TimeZone.getTimeZone("Asia/Bahrain"));
long time_in_milliseconds = 0;
Date date = new Date();
try {
date = sdf.parse(givenDateString);
} catch (ParseException e) {
e.printStackTrace();
}
time_in_milliseconds = date.getTime();
final CharSequence ch = DateUtils.getRelativeTimeSpanString(time_in_milliseconds
, System.currentTimeMillis(), DateUtils.MINUTE_IN_MILLIS);
holder.search_task_time_ago.setText(ch);
holder.search_task_linear_layout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
postKey = getRef(holder.getAdapterPosition()).getKey();
Bundle bundle = new Bundle();
Intent goToTaskDetails = new Intent(Search_task_list.this, task_details.class);
bundle.putString("post_key", postKey);
bundle.putString("poster_id", model.getPoster_id());
goToTaskDetails.putExtras(bundle);
startActivity(goToTaskDetails);
}
});
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.search_task_design_details, parent, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
};
search_task_list_recycler.setAdapter(adapter);
adapter.startListening();
}
//================================================================
public static class ViewHolder extends RecyclerView.ViewHolder {
public CircleImageView search_task_user_image;
public AppCompatTextView search_task_topic_title;
public AppCompatTextView search_task_due_date;
public AppCompatTextView search_task_preferred_timing;
public AppCompatTextView search_task_location;
public AppCompatTextView search_task_time_ago;
public AppCompatTextView search_task_job_status;
public AppCompatTextView search_task_budget;
public LinearLayout search_task_linear_layout;
public ViewHolder(View itemView) {
super(itemView);
search_task_user_image = itemView.findViewById(R.id.search_task_user_image);
search_task_topic_title = itemView.findViewById(R.id.search_task_topic_title);
search_task_due_date = itemView.findViewById(R.id.search_task_due_date);
search_task_preferred_timing = itemView.findViewById(R.id.search_task_preferred_timing);
search_task_location = itemView.findViewById(R.id.search_task_location);
search_task_time_ago = itemView.findViewById(R.id.search_task_time_ago);
search_task_job_status = itemView.findViewById(R.id.search_task_job_status);
search_task_budget = itemView.findViewById(R.id.search_task_budget);
search_task_linear_layout = itemView.findViewById(R.id.search_task_linear_layout);
}
}
只要从firebase数据库中获取了firebase base recyclerview数据，进度对话框就应该显示。取决于其他因素（例如Internetspeed或其他因素），它可能是1秒或2秒或更长时间。
答案 0 :(得分：0)
请尝试
private ProgressDialog loadingBar;
onCreate(Bundle savedInstanceState) {
// loading bar
loadingBar = new ProgressDialog(this);
loadingBar.setMessage("Please wait...");
loadingBar.setCanceledOnTouchOutside(false);
loadingBar.show();
displayTasks();
}
在您的displayTasks（）
中
private void displayTasks()
{
search_task_list_recycler.setAdapter(adapter);
adapter.startListening();
//here add
loadingBar.dismiss();
}
希望这会对您有所帮助。