通过用户数组列表从Firebase检索数据

时间：2020-09-05 17:24:05

标签： java android database firebase

我有如下所示的firebse数据库。

This is the database

我正在尝试通过下面显示的Users类的数组列表中的User类的对象获取所有用户的详细信息。这样我以后就可以从用户数组列表访问用户的所有信息。我试图迭代一个for循环，以遍历每个用户并为他们提供详细信息。如果我只使用一个User类，并且只尝试让一个用户详细说明它正在运行，但是如果使用arraylist，它将无法初始化该数组。

final DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("users");

        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()){

                    Log.d("Members", "Fill User Array");
                    usersArray.add(dataSnapshot1.getValue(User.class));

                }

            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

我的User类在下面

package com.aam.mkc;

public class User {
    private String username;
    private String roll;
    private String phone;
    private String email;
    private String password;

    public User() {
    }

    public User(String username, String roll, String phone, String email, String password) {
        this.username = username;
        this.roll = roll;
        this.phone = phone;
        this.email = email;
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getRoll() {
        return roll;
    }

    public void setRoll(String roll) {
        this.roll = roll;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    } }

但是它不起作用。调试应用程序显示arraylist大小为0。

下面显示的调试消息。

dataSnapshot = {DataSnapshot@8946} "DataSnapshot { key = users, value = {SKCtzaeoNnYfB3QLNZEx0fRkrjC2={password=password, phone=01518555666, roll=47, email=tasrifajuni44@gmail.com, username=Tasrifa islam}, XiXJGeb2PuR8sNg59mF0dkY7wI83={password=password, phone=01587112255, roll=14, email=aamasudrana2020@gmail.com, username=MASUD RANA}, W9sHjQGiGZgCJL8VxiUdkf4lduw1={password=password, phone=01518600135, roll=32, email=abdullahalmasum777@gmail.com, username=ABDULLAH AL MASUM}} }"
usersArray = {ArrayList@8949}  size = 0
dataSnapshot1 = {DataSnapshot@8947} "DataSnapshot { key = SKCtzaeoNnYfB3QLNZEx0fRkrjC2, value = {password=password, phone=01518555666, roll=47, email=tasrifajuni44@gmail.com, username=Tasrifa islam} }"
this = {Members$1@8945}


    //Logcat
    Build Date                       : 03/01/19
    OpenGL ES Shader Compiler Version: EV031.25.03.02
    Local Branch                     : 
    Remote Branch                    : refs/tags/AU_LINUX_ANDROID_LA.UM.7.5.R1.09.00.00.464.039
    Remote Branch                    : NONE
    Reconstruct Branch               : NOTHING
2020-09-02 19:49:39.363 4485-4541/com.aam.mkc I/Adreno: Build Config                     : S L 6.0.7 AArch32
2020-09-02 19:49:39.368 4485-4541/com.aam.mkc I/Adreno: PFP: 0x005ff110, ME: 0x005ff066
2020-09-02 19:49:39.374 4485-4541/com.aam.mkc I/ConfigStore: android::hardware::configstore::V1_0::ISurfaceFlingerConfigs::hasWideColorDisplay retrieved: 0
2020-09-02 19:49:39.374 4485-4541/com.aam.mkc I/ConfigStore: android::hardware::configstore::V1_0::ISurfaceFlingerConfigs::hasHDRDisplay retrieved: 0
2020-09-02 19:49:39.375 4485-4541/com.aam.mkc I/OpenGLRenderer: Initialized EGL, version 1.4
2020-09-02 19:49:39.375 4485-4541/com.aam.mkc D/OpenGLRenderer: Swap behavior 2
2020-09-02 19:49:40.356 4485-4540/com.aam.mkc I/Timeline: Timeline: Activity_launch_request time:145685894
2020-09-02 19:49:40.393 4485-4485/com.aam.mkc W/ActivityThread: handleWindowVisibility: no activity for token android.os.BinderProxy@d2fe96d
2020-09-02 19:49:40.815 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/widget/TextView;->getTextDirectionHeuristic()Landroid/text/TextDirectionHeuristic; (light greylist, linking)
2020-09-02 19:49:41.167 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden field Landroid/view/View;->mAccessibilityDelegate:Landroid/view/View$AccessibilityDelegate; (light greylist, reflection)
2020-09-02 19:49:41.565 4485-4485/com.aam.mkc W/Activity: Slow Operation: Activity com.aam.mkc/.MainActivity onCreate took 1083ms
2020-09-02 19:49:41.732 4485-4485/com.aam.mkc W/Activity: Slow Operation: Activity com.aam.mkc/.MainActivity onStart took 131ms
2020-09-02 19:49:42.375 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/graphics/FontFamily;-><init>()V (light greylist, reflection)
2020-09-02 19:49:42.375 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/graphics/FontFamily;->addFontFromAssetManager(Landroid/content/res/AssetManager;Ljava/lang/String;IZIII[Landroid/graphics/fonts/FontVariationAxis;)Z (light greylist, reflection)
2020-09-02 19:49:42.375 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/graphics/FontFamily;->addFontFromBuffer(Ljava/nio/ByteBuffer;I[Landroid/graphics/fonts/FontVariationAxis;II)Z (light greylist, reflection)
2020-09-02 19:49:42.375 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/graphics/FontFamily;->freeze()Z (light greylist, reflection)
2020-09-02 19:49:42.375 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/graphics/FontFamily;->abortCreation()V (light greylist, reflection)
2020-09-02 19:49:42.376 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/graphics/Typeface;->createFromFamiliesWithDefault([Landroid/graphics/FontFamily;Ljava/lang/String;II)Landroid/graphics/Typeface; (light greylist, reflection)
2020-09-02 19:49:43.512 4485-4485/com.aam.mkc I/Choreographer: Skipped 96 frames!  The application may be doing too much work on its main thread.
2020-09-02 19:49:43.766 4485-4541/com.aam.mkc I/OpenGLRenderer: Davey! duration=1867ms; Flags=0, IntendedVsync=145687436834827, Vsync=145689036834763, OldestInputEvent=9223372036854775807, NewestInputEvent=0, HandleInputStart=145689052656610, AnimationStart=145689052982755, PerformTraversalsStart=145689053030099, DrawStart=145689091094370, SyncQueued=145689235642755, SyncStart=145689235896974, IssueDrawCommandsStart=145689236288328, SwapBuffers=145689303856557, FrameCompleted=145689305083797, DequeueBufferDuration=2009000, QueueBufferDuration=532000, 
2020-09-02 19:49:43.773 4485-4485/com.aam.mkc W/Looper: Slow Looper: doFrame is 1614ms late because of 2 msg, msg 1 took 1500ms (late=1ms h=android.view.Choreographer$FrameHandler c=android.view.Choreographer$FrameDisplayEventReceiver), msg 2 took 213ms (late=1442ms h=android.view.ViewRootImpl$ViewRootHandler c=androidx.appcompat.app.AppCompatDelegateImpl$2)
2020-09-02 19:49:45.276 4485-4485/com.aam.mkc W/com.aam.mkc: Verification of void com.aam.mkc.Members.onViewCreated(android.view.View, android.os.Bundle) took 147.234ms
2020-09-02 19:49:45.311 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->getTransitionAlpha()F (light greylist, linking)
2020-09-02 19:49:45.312 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->setTransitionAlpha(F)V (light greylist, linking)
2020-09-02 19:49:45.313 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->setAnimationMatrix(Landroid/graphics/Matrix;)V (light greylist, linking)
2020-09-02 19:49:45.313 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->transformMatrixToGlobal(Landroid/graphics/Matrix;)V (light greylist, linking)
2020-09-02 19:49:45.313 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->transformMatrixToLocal(Landroid/graphics/Matrix;)V (light greylist, linking)
2020-09-02 19:49:45.314 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->setLeftTopRightBottom(IIII)V (light greylist, linking)
2020-09-02 19:49:45.314 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/View;->setTransitionVisibility(I)V (dark greylist, linking)
2020-09-02 19:49:45.618 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden field Landroid/view/View;->mViewFlags:I (light greylist, reflection)
2020-09-02 19:49:45.621 4485-4485/com.aam.mkc W/com.aam.mkc: Accessing hidden method Landroid/view/ViewGroup;->suppressLayout(Z)V (light greylist, linking)
2020-09-02 19:49:45.750 4485-4485/com.aam.mkc W/Looper: Slow Looper: doFrame is 353ms late because of 2 msg, msg 2 took 343ms (late=26ms h=android.view.ViewRootImpl$ViewRootHandler c=android.view.View$PerformClick)
2020-09-02 19:49:47.285 4485-4485/com.aam.mkc W/Looper: Slow Looper: doFrame is 363ms late because of 3 msg, msg 1 took 288ms (late=353ms h=android.view.Choreographer$FrameHandler c=android.view.Choreographer$FrameDisplayEventReceiver), msg 3 took 237ms (late=474ms h=android.os.Handler c=androidx.fragment.app.FragmentManagerImpl$2)
2020-09-02 19:49:47.287 4485-4485/com.aam.mkc I/Choreographer: Skipped 75 frames!  The application may be doing too much work on its main thread.
2020-09-02 19:49:47.289 4485-4541/com.aam.mkc I/OpenGLRenderer: Davey! duration=1647ms; Flags=0, IntendedVsync=145691179814869, Vsync=145691529814855, OldestInputEvent=9223372036854775807, NewestInputEvent=0, HandleInputStart=145691542530932, AnimationStart=145691542851244, PerformTraversalsStart=145691553275202, DrawStart=145692737066660, SyncQueued=145692816829889, SyncStart=145692816994681, IssueDrawCommandsStart=145692817545775, SwapBuffers=145692825474681, FrameCompleted=145692827469681, DequeueBufferDuration=448000, QueueBufferDuration=1030000, 
2020-09-02 19:49:47.340 4485-4541/com.aam.mkc I/OpenGLRenderer: Davey! duration=1314ms; Flags=0, IntendedVsync=145691564245589, Vsync=145692814245539, OldestInputEvent=9223372036854775807, NewestInputEvent=0, HandleInputStart=145692827001087, AnimationStart=145692827080775, PerformTraversalsStart=145692863948952, DrawStart=145692866082077, SyncQueued=145692874263379, SyncStart=145692874452546, IssueDrawCommandsStart=145692874733119, SwapBuffers=145692877656556, FrameCompleted=145692878947702, DequeueBufferDuration=361000, QueueBufferDuration=636000, 
2020-09-02 19:49:47.340 4485-4485/com.aam.mkc W/Looper: Slow Looper: doFrame is 1261ms late because of 1 msg, msg 1 took 1275ms (late=363ms h=android.view.Choreographer$FrameHandler c=android.view.Choreographer$FrameDisplayEventReceiver)
2020-09-02 19:49:47.402 4485-4559/com.aam.mkc D/NetworkSecurityConfig: No Network Security Config specified, using platform default
2020-09-02 19:49:52.470 4485-4485/com.aam.mkc D/Members: Fill User Array.   //why only one iteration

如果还有其他事情要通知，请通知。 这是我要访问用户的数组列表的类。

package com.aam.mkc;

import android.content.Context;
import android.net.Uri;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;

public class MembersListViewAdapter extends BaseAdapter {

    Context context;
    ArrayList<User> usersArray;

    public MembersListViewAdapter(Context context, ArrayList<User> usersArray) {
        this.context = context;
        this.usersArray = usersArray;
    }

    @Override
    public int getCount() {
        return (usersArray.size() == 0)?70:usersArray.size();   //here shows arraylist size is 0
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater = LayoutInflater.from(context);
        convertView = inflater.inflate(R.layout.members_single_listview, parent, false);


        ImageView profileImg = (ImageView) convertView.findViewById(R.id.member_user_profile_img);
        TextView name = (TextView) convertView.findViewById(R.id.tv_members_profile_name);
        TextView roll = (TextView) convertView.findViewById(R.id.tv_members_roll);

//        profileImg.setImageURI(images[position]);
//        name.setText(names[position]);
//        roll.setText(rolls[position]);

        return convertView;
    }
}

1 个答案:

答案 0 :(得分：0)

使用特定的ISP时，某些firebase服务器已关闭，甚至在使用Vodafone网络时，我的实时数据库也无法访问，您应该检查一下您是否认为自己没有错。 https://status.firebase.google.com/incident/Realtime%20Database/20008

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