java My代码仅从数据库的第一个字段检索数据。请查看详细信息

11 月，3 周 Questions & Answers 116

我写了一些代码，从firebase数据库中检索数据

问题是，我的代码只从数据库中的第一个数据字段中检索数据，而不是从所有字段中检索数据

我想让它从我数据库的每个字段中检索数据

这是我的代码：

retrieveRef = new Firebase("https://appname.firebaseio.com/hDetails/");

retrieveRef.addChildEventListener(new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String s) {
        hDescription = (String) dataSnapshot.child("hDescription").getValue();
        hImage = (String) dataSnapshot.child("hImage").getValue();
        hLat = (String) dataSnapshot.child("hLat").getValue();
        hLng = (String) dataSnapshot.child("hLng").getValue();
        postedAtTime = (String) dataSnapshot.child("postedAtTime").getValue();
        postedBy = (String) dataSnapshot.child("postedBy").getValue();
        postedOnDate = (String) dataSnapshot.child("postedOnDate").getValue();
    }

    @Override
    public void onChildChanged(DataSnapshot dataSnapshot, String s) {

    }

    @Override
    public void onChildRemoved(DataSnapshot dataSnapshot) {

    }

    @Override
    public void onChildMoved(DataSnapshot dataSnapshot, String s) {

    }

    @Override
    public void onCancelled(FirebaseError firebaseError) {
        Toast.makeText(getBaseContext(), firebaseError.getMessage(),
                Toast.LENGTH_SHORT).show();
    }
});

以下是我的数据库的图片：

仅从最后一个字段检索数据，即每次f4452618-a073-4868-a9c6-050b055b4861

以下是build.gradle（模块：app）：

    apply plugin: 'com.安卓.application'

    安卓 {

        compileSdkVersion 23
        buildToolsVersion "23.0.2"
        defaultConfig {
            applicationId "com.abc.xyz"
            minSdkVersion 16
            targetSdkVersion 23
            versionCode 5
            versionName "0.4"
            multiDexEnabled true;
        }
        packagingOptions {
            exclude 'META-INF/LICENSE'
            exclude 'META-INF/LICENSE-FIREBASE.txt'
            exclude 'META-INF/NOTICE'
        }
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-安卓.txt'), 'proguard-rules.pro'
                signingConfig signingConfigs.config
            }
        }
    }

    dependencies {
        compile fileTree(dir: 'libs', include: ['*.jar'])
        testCompile 'junit:junit:4.12'
        compile 'com.安卓.support:appcompat-v7:23.4.0'
        compile 'com.安卓.support:design:23.4.0'
        compile 'com.安卓.support:cardview-v7:23.4.0'
        compile 'com.安卓.support:recyclerview-v7:23.4.0'
        compile 'com.firebase:firebase-client-安卓:2.3.1'
        compile 'com.firebaseui:firebase-ui:0.3.1'
        compile 'com.facebook.安卓:facebook-安卓-sdk:4.1.0'
        compile 'com.google.安卓.gms:play-services-maps:9.0.0'
        compile 'com.google.安卓.gms:play-services-plus:9.0.0'
        compile 'com.安卓.support:support-v4:23.4.0'
        compile 'com.squareup.picasso:picasso:2.5.2'
        compile 'com.google.安卓.gms:play-services-location:9.0.0'
        compile 'com.firebase:geofire:1.1.0'
        compile 'com.google.firebase:firebase-database:9.0.1'
        compile 'io.github.yavski:fab-speed-dial:1.0.4'
        compile 'com.google.gms:google-services:3.0.0'
    }

apply plugin: 'com.google.gms.google-services'

以下是buid.gradle（项目名称：projectname）：

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.安卓.tools.build:gradle:2.1.0'
        classpath 'com.google.gms:google-services:3.0.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

这里怎么了

请告诉我

抱歉，如果问题似乎格式不正确。我在这里还是个初学者

FirebaseDatabase database = FirebaseDatabase.getInstance(); DatabaseReference retrieveRef = database.getReference("hDetails"); final List<YourPOJO> pojoList = new ArrayList<>(); retrieveRef.addChildEventListener(new ChildEventListener() { @Override public void onChildAdded(DataSnapshot dataSnapshot, String s) { pojoList.clear(); for (DataSnapshot snapshot : dataSnapshot.getChildren()) { pojoList.add(snapshot.getValue(YourPOJO.class)); } } @Override public void onChildChanged(DataSnapshot dataSnapshot, String s) { } @Override public void onChildRemoved(DataSnapshot dataSnapshot) { } @Override public void onChildMoved(DataSnapshot dataSnapshot, String s) { } @Override public void onCancelled(FirebaseError firebaseError) { Toast.makeText(getBaseContext(), firebaseError.getMessage(), Toast.LENGTH_SHORT).show(); } });

dependencies { compile 'com.google.firebase:firebase-core:9.0.0' compile 'com.google.firebase:firebase-auth:9.0.0' compile 'com.google.firebase:firebase-database:9.0.0' } apply plugin: 'com.google.gms.google-services'

DatabaseReference root = FirebaseDatabase.getInstance(). getReferenceFromUrl("https://appname.firebaseio.com/hDetails/"); Query playlistQuery = root.orderByKey(); playlistQuery.addChildEventListener(new ChildEventListener() { @Override public void onChildAdded(DataSnapshot dataSnapshot, String s) { //Make sure you have a empty constructor to de-serialize it YourPOJO playlist = dataSnapshot.getValue(YourPOJO.class); playlist.getName(); // Depends on the field names playlist.getDetails(); .... } @Override public void onChildChanged(DataSnapshot dataSnapshot, String s) { } @Override public void onChildRemoved(DataSnapshot dataSnapshot) { } @Override public void onChildMoved(DataSnapshot dataSnapshot, String s) { } @Override public void onCancelled(DatabaseError databaseError) { } });

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java My代码仅从数据库的第一个字段检索数据。请查看详细信息

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