问题：
Firebase数据库未从Firebase数据库引用中提取数据
越信鸥
一切正常，但DatabaseReference无法获取数据，这就像是忽略了我的代码运行，就像我的internet无法运行一样，请帮助我，我是这个社区的新手，下面是我的代码和图片。
以前它是工作的，但由于我只是更改了一些代码，使只有currentVersion>=vCode，这样即使数据库中的值是
firebase数据库映像
mainactivity.java
public class MainActivity extends AppCompatActivity {
TextView appName;
FirebaseUser firebaseUser;
String currentVersionName;
long currentVersionCode;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
appName = findViewById(R.id.appName);
currentVersionName = BuildConfig.VERSION_NAME;
currentVersionCode = BuildConfig.VERSION_CODE;
animateAppName();
netConn();
FirebaseAuth.getInstance();
}
public void applyScreenChange(){
String sharedPerfId = "MyAppPref";
SharedPreferences sharedPreferences = getSharedPreferences(sharedPerfId,0);
boolean isAdvertiserLoggedIn = sharedPreferences.getBoolean("isAdvertiserLoggedIn",false);
boolean isCreatorLoggedIn = sharedPreferences.getBoolean("isCreatorLoggedIn",false);
if (isAdvertiserLoggedIn){
skipSetupToAdvertiser();
}
else if (isCreatorLoggedIn){
skipSetupToCreator();
}
else {
newActivity();
}
}
public void animateAppName(){
appName.setTranslationY(-1000f);
appName.animate().translationYBy(1000f).setDuration(500);
}
public void netConn(){
ConnectivityManager connectivityManager = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
assert connectivityManager != null;
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
if(networkInfo == null || !networkInfo.isConnected() || !networkInfo.isAvailable()){
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("No Internet Connection");
alertDialog.setMessage("Connect to Network and Then try again");
alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "Exit", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
MainActivity.super.onBackPressed();
}
});
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Retry", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
netConn();
}
});
alertDialog.setCanceledOnTouchOutside(false);
alertDialog.show();
}else {
// Check older version
// applyScreenChange();
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Version");
databaseReference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
String vName = (String) snapshot.child("latestVersionName").getValue();
long vCode = (long) snapshot.child("latestVersionCode").getValue();
if (currentVersionName.equals(vName) && currentVersionCode >= vCode){
applyScreenChange();
// TODO: 16-08-2020 add condition to open app if version is higher
}else {
Toast.makeText(MainActivity.this, "Old Version", Toast.LENGTH_SHORT).show();
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("You're on Older Version");
alertDialog.setMessage("This Version is no more supported, Kindly update your App to Continue");
alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "Exit", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
MainActivity.super.onBackPressed();
}
});
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Update", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
// startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.app_link))));
Toast.makeText(MainActivity.this, "Kindly Search Sponso on PlayStore and Update", Toast.LENGTH_SHORT).show();
finish();
}
});
alertDialog.setCanceledOnTouchOutside(false);
alertDialog.show();
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
}
}
public void newActivity(){
Intent intent = new Intent(MainActivity.this, AdvertiserCreatorChooser.class);
startActivity(intent);
finish();
}
public void skipSetupToAdvertiser(){
firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
if (firebaseUser!=null) {
Intent intent = new Intent(MainActivity.this, AdvertiserHome.class);
startActivity(intent);
finish();
}else{
Intent intent = new Intent(MainActivity.this, AdvertiserLoginRegister.class);
startActivity(intent);
finish();
}
}
public void skipSetupToCreator(){
firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
if (firebaseUser!=null) {
Intent intent = new Intent(MainActivity.this, CreatorHome.class);
startActivity(intent);
finish();
}else {
Intent intent = new Intent(MainActivity.this, CreatorLoginRegister.class);
startActivity(intent);
finish();
}
}
}
manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.webroose.sponso">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<application
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:allowBackup="true"
android:theme="@style/AppTheme">
<activity android:name=".Advertiser.AdvertiserCampaignUpdate"/>
<activity android:name=".Advertiser.ui.main.AdvertiserSettings" />
<activity android:name=".Creator.CreatorRecentlyChat" />
<activity android:name=".Advertiser.AdvertiserRecentlyChat" />
<activity android:name=".Advertiser.AdvertiserChatActivity" />
<activity android:name=".Creator.CreatorChatActivity" />
<meta-data
android:name="com.google.android.gms.ads.APPLICATION_ID"
android:value="@string/app_id" />
<activity android:name=".Creator.CreatorUserDetails" />
<activity android:name=".Creator.CreatorList" />
<activity android:name=".Common.AboutUs" />
<activity
android:name=".AdvertiserHome"
android:label="@string/title_activity_advertiser_home"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Advertiser.AdvertiserLoginRegister"
android:label="@string/title_activity_advertiser_login_register"
android:theme="@style/AppTheme.NoActionBar" />
<activity android:name=".Common.PrivacyPolicy" />
<activity android:name=".Common.ChangePassword" />
<activity android:name=".Creator.CreatorSettings" />
<activity android:name=".Common.ChangeEmail" />
<activity android:name=".Advertiser.AdvertiserUserDetails" />
<activity android:name=".Advertiser.AdvertiserList" />
<activity
android:name=".CreatorHome"
android:label="@string/title_activity_creator_home"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Creator.CreatorLoginRegister"
android:label="@string/title_activity_creator_login_register"
android:theme="@style/AppTheme.NoActionBar" />
<activity android:name=".AdvertiserCreatorChooser" />
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="preloaded_fonts"
android:resource="@array/preloaded_fonts" />
</application>
</manifest>
依赖关系
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
implementation 'com.google.android.material:material:1.2.0'
implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
implementation 'com.google.firebase:firebase-database:19.4.0'
implementation 'androidx.legacy:legacy-support-v4:1.0.0'
implementation 'androidx.navigation:navigation-fragment:2.3.0'
implementation 'androidx.navigation:navigation-ui:2.3.0'
testImplementation 'junit:junit:4.13'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
implementation 'com.google.firebase:firebase-auth:19.3.2'
implementation 'com.google.firebase:firebase-database:19.4.0'
implementation 'com.firebaseui:firebase-ui-database:6.2.0'
implementation 'com.google.android.gms:play-services-ads:19.3.0'
implementation 'com.android.support:multidex:2.0.0'
implementation 'com.google.firebase:firebase-analytics:17.5.0'
implementation 'com.google.firebase:firebase-messaging:20.2.4'
implementation 'com.facebook.android:audience-network-sdk:5.10.1'
}
共有2个答案
鲜于子琪
而实际问题是Firebase数据库
用firebase数据库检查下面的图像
郑胡媚
将databaseReference databaseReference=FirebaseDatabase.GetInstance（）.GetReference（“Version”）；
更改为databaseReference databaseReference=FirebaseDatabase.GetInstance（）.GetReference（）.Child（“Version”）；
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