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我试图用火力地堡数据库,但现在面临非法状态异常非法状态异常火力地堡数据库
默认FirebaseApp没有在这个过程中com。示例初始化。 请确保先调用FirebaseApp.initializeApp(Context)。
我创建了一个Utility类,可以从任何地方实例化。我在Application和Activity(onCreate)级别都尝试过,结果是一样的。
public class FirebaseUtils {
private static final String TAG = FirebaseUtils.class.getSimpleName();
private static FirebaseDatabase mFirebaseDatabase;
private static DatabaseReference mDbReference;
// listeners
private static OnFirebaseValueListener mFirebaseValueListener;
/**
* Method is used to set callback to listen to value changes in Firebase DB
*
* @param listener
*/
public static void onFirebaseValueListener(OnFirebaseValueListener listener) {
mFirebaseValueListener = listener;
}
/**
* Constructor
*/
public FirebaseUtils(Context context) {
FirebaseApp.initializeApp(context);
mFirebaseDatabase = FirebaseDatabase.getInstance();
mDbReference = mFirebaseDatabase.getReference();
}
/**
* Method is used to add a list of values to Firebase DB
*
* @param alHistory
*/
public static void addValues(List<?> alHistory) {
if (!FrameworkUtils.checkIfNull(mDbReference)) {
// set value
mDbReference.setValue(alHistory);
mDbReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.i(TAG, "<onDataChange> successful!");
if (!FrameworkUtils.checkIfNull(mFirebaseValueListener)) {
mFirebaseValueListener.onDataChange(dataSnapshot);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
if (!FrameworkUtils.checkIfNull(databaseError) && !FrameworkUtils.isStringEmpty(databaseError.getMessage())) {
Log.i(TAG, "<onCancelled> error: " + databaseError.getMessage());
if (!FrameworkUtils.checkIfNull(mFirebaseValueListener)) {
mFirebaseValueListener.onCancelled(databaseError);
}
}
}
});
}
}
/**
* Method is used to retrieve a list of values from Firebase DB
*/
public static void retrieveValues() {
mDbReference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.i(TAG, "<onDataChange> successful!");
if (!FrameworkUtils.checkIfNull(mFirebaseValueListener)) {
mFirebaseValueListener.onDataChange(dataSnapshot);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
if (!FrameworkUtils.checkIfNull(databaseError) && !FrameworkUtils.isStringEmpty(databaseError.getMessage())) {
Log.i(TAG, "<onCancelled> error: " + databaseError.getMessage());
if (!FrameworkUtils.checkIfNull(mFirebaseValueListener)) {
mFirebaseValueListener.onCancelled(databaseError);
}
}
}
});
}
}
我实例化这样
// instantiate FirebaseUtils
new FirebaseUtils(this);
我在gradle这个加了我所有的依赖
dependencies {
compile 'com.google.firebase:firebase-database:10.2.1'
}
我在清单
上网权限<uses-permission android:name="android.permission.INTERNET" />
有一些安装的种类我失踪的Firebase?