我无法在我的回收器视图上显示任何项目。我确定我的数据库连接很好。
但最后，它在回收器视图中什么都做不了，我不知道会发生什么，因为我只接触了 android 工作室 2 周。
这是我的数据库结构
Root
|
|__restaurant
|_____name
|_____1
|_____lat: "22.34554"
|_____long: "34.124253"
|_____name: "A"
|_____2
|_____lat: "24.34554"
|_____long: "35.124253"
|_____name: "B"
I want to show all restaurant name like A, B
这是我的活动(nearActivity.java(
package com.example.chanyuenpan.garretproject3;
import android.arch.lifecycle.LifecycleObserver;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.firebase.ui.database.ObservableSnapshotArray;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
public class nearActivity extends AppCompatActivity {
private restaurant restaurant;
private DatabaseReference myRef;
private RecyclerView recyclerView;
private static final String TAG = "FirebaseRecyclerAdapter";
Query query = FirebaseDatabase.getInstance()
.getReference()
.child("chats")
.limitToLast(50);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_near);
myRef = FirebaseDatabase.getInstance().getReference().child("Restaurant");
myRef.keepSynced(true);
recyclerView = (RecyclerView) findViewById(R.id.my_RevlerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
final FirebaseDatabase database = FirebaseDatabase.getInstance();
FirebaseRecyclerOptions<restaurant> options =
new FirebaseRecyclerOptions.Builder<restaurant>()
.setQuery(myRef, restaurant.class)
.build();
FirebaseRecyclerAdapter<restaurant, myViewHolder> adapter =
new FirebaseRecyclerAdapter<restaurant, myViewHolder>(options) {
@Override
protected void onBindViewHolder(@NonNull myViewHolder holder, int position, @NonNull restaurant model) {
holder.myTextView.setText(model.getName());
}
@Override
public myViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.activity_near, parent, false);
return new nearActivity.myViewHolder(view);
}
};
recyclerView.setAdapter(adapter);
}
public static class myViewHolder extends RecyclerView.ViewHolder{
public TextView myTextView;
public myViewHolder(View itemView){
super(itemView);
myTextView = itemView.findViewById(android.R.id.text1);
}
}
}
这是我的 xml (activity_near.xml(
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.chanyuenpan.garretproject3.nearActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/my_RevlerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>
这是我的餐厅.java(类(
package com.example.chanyuenpan.garretproject3;
import java.io.Serializable;
public class restaurant implements Serializable {
String mlat;
String mlogi;
String mname;
public restaurant(){}
public restaurant (String lat, String logi, String name){
mlat = lat;
mlogi = logi;
mname = name;
}
public String getlat() {
return mlat;
}
public void setLong(String logi) { mlogi = logi; }
public String getlogi(){
return mlogi;
}
public void setLat(String lat) { mlat = lat; }
public String getName(){
return mname;
}
public void setName(String name) { mname = name; }
}
这是我的build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
defaultConfig {
applicationId "com.example.chanyuenpan.garretproject3"
minSdkVersion 25
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'com.google.android.gms:play-services-maps:11.8.0'
implementation 'com.google.android.gms:play-services-location:11.8.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
compile 'com.google.firebase:firebase-core:11.8.0'
compile 'com.google.firebase:firebase-database:11.8.0'
compile 'com.google.firebase:firebase-storage:11.8.0'
compile 'com.google.firebase:firebase-auth:11.8.0'
compile 'com.android.support:cardview-v7:26.1.0'
compile 'com.android.support:recyclerview-v7:26.1.0'
compile 'com.firebaseui:firebase-ui-database:3.2.2'
compile 'com.firebaseui:firebase-ui:3.2.2'
compile 'com.firebaseui:firebase-ui-auth:3.2.2'
implementation 'com.firebaseui:firebase-ui-storage:3.2.2'
implementation 'com.firebaseui:firebase-ui-firestore:3.2.2'
implementation 'com.android.support:design:26.1.0'
}
apply plugin: 'com.google.gms.google-services'
有几点是错误的：
- 您的数据类应该使用一致的 getter 和 setter(因此
getlogi应getLong(并具有private字段。(另外，getlat应该是getLat.二传手看起来不错。 - 您传递到回收器选项生成器的查询不正确：它应该是
FirebaseDatabase.getInstance().getReference().child("restaurant").child("name").limitToLast(50);。我建议也摆脱不必要的name文件夹。 - 所有其他对 Firebase 数据库的引用都应移除，因为它们的大小写不正确，并且无助于填充回收器视图。
FirebaseRecyclerOptions构建器应包括对setLifecycleOwner(this)的调用。