小编Sah*_*ana的帖子

我正在使用firebase从数据库中检索数据

Map<String, String> map = dataSnapshot.getValue(Map.class);

获取值,但它显示错误

E/AndroidRuntime: FATAL EXCEPTION: main
                                                                 Process: com.rana.sahaj.myyu, PID: 13179
                                                                 com.google.firebase.database.DatabaseException: Class java.util.Map has generic type parameters, please use GenericTypeIndicator instead
                                                                     at com.google.android.gms.internal.zzaix.zzb(Unknown Source)
                                                                     at com.google.android.gms.internal.zzaix.zza(Unknown Source)
                                                                     at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
                                                                     at com.rana.sahaj.myyu.profile.Profile$2.onDataChange(Profile.java:158)
                                                                     at com.google.android.gms.internal.zzafp.zza(Unknown Source)
                                                                     at com.google.android.gms.internal.zzagp.zzSu(Unknown Source)
                                                                     at com.google.android.gms.internal.zzags$1.run(Unknown Source)
                                                                     at android.os.Handler.handleCallback(Handler.java:733)
                                                                     at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                     at android.os.Looper.loop(Looper.java:136)
                                                                     at android.app.ActivityThread.main(ActivityThread.java:5052)
                                                                     at java.lang.reflect.Method.invokeNative(Native Method)
                                                                     at java.lang.reflect.Method.invoke(Method.java:515)
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
                                                                     at dalvik.system.NativeStart.main(Native Method)

这是代码

 DatabaseReference profileRef=mFirebaseRef.child(EEmail);
    profileRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

    -->     Map<String, …

将Realm升级1.1.0为2.0.2.我在处理对象时遇到此错误.在早期版本中,它工作正常.

io.realm.exceptions.RealmException:'RealmNoticeModelClass'有一个主键,改为使用'createObject(Class,Object)'.

E/AndroidRuntime: FATAL EXCEPTION: main
                                                                 Process: com.rana.sahaj.myyu, PID: 20202
                                                                 io.realm.exceptions.RealmException: 'RealmNoticeModelClass' has a primary key, use 'createObject(Class<E>, Object)' instead.
                                                                     at io.realm.Realm.createObjectInternal(Realm.java:821)
                                                                     at io.realm.Realm.createObject(Realm.java:802)
                                                                     at com.rana.sahaj.myyu.notice.NoticeOnItemSelectedActivity$1$2.onSuccess(NoticeOnItemSelectedActivity.java:162)
                                                                     at com.rana.sahaj.myyu.notice.NoticeOnItemSelectedActivity$1$2.onSuccess(NoticeOnItemSelectedActivity.java:156)
                                                                     at com.google.android.gms.tasks.zze$1.run(Unknown Source)
                                                                     at android.os.Handler.handleCallback(Handler.java:733)
                                                                     at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                     at android.os.Looper.loop(Looper.java:136)
                                                                     at android.app.ActivityThread.main(ActivityThread.java:5052)
                                                                     at java.lang.reflect.Method.invokeNative(Native Method)
                                                                     at java.lang.reflect.Method.invoke(Method.java:515)
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
                                                                     at dalvik.system.NativeStart.main(Native Method)

代码是

 realm.beginTransaction();
                    RealmNoticeModelClass realmNoticeModelClass = realm.createObject(RealmNoticeModelClass.class);
                    realmNoticeModelClass.setDocUrl(DocUrl1);
                    realmNoticeModelClass.setHashname(heading);
                    realmNoticeModelClass.setContent(contentString);
                    realmNoticeModelClass.setTime(getIntent().getExtras().getString("notice_time"));
                    realmNoticeModelClass.setPicurl(picUrlName);
                    realmNoticeModelClass.setUserPic(getIntent().getExtras().getString("image_user_notice"));
                    realmNoticeModelClass.setPdfUrl(PdfUrl);
                    realmNoticeModelClass.setPicOffline(SnapshotKey);
                    realmNoticeModelClass.setMetaType(null);
                    realmNoticeModelClass.setTimeStamp(SnapshotKey);
                    realm.commitTransaction();

n RealmNoticeModelClass

public class RealmNoticeModelClass extends RealmObject { …

我想知道如果新的firebase数据库添加了这个功能,因为我在我的项目中需要它.

结构看起来像这样..

并设置RecyclerView反转对我不起作用,因为这会导致它从底部开始.

解

所以,这是我能想到的最好的解决方案.现在.

正如@Frank所说这可能是重复但我最初在他的帮助下解决了它.

所以我们能做的就是让timeStamp为负,即-20164846476589

然后用一些更高的值减去它,如999999999999999L(现在我们不会超过offcourse)然后我们得到的将是新时间戳的最低降序值

并且数据将在Firebase中自动降序

即

 String NewDescTimeStamp= String.valueOf((9999999999999L+(-1 * PreviousTimestamp)));

 mFirebaseRef.child(NewDescTimeStamp).setValue(true);

我目前正在使用firebase RecyclerView帮助添加朋友,如果用户点击ADD按钮,他将被添加到数据库n中,需要永久删除所需的项目..所以,如何通过firebase模型实现它因为我们没有任何数据列表要删除..

这是代码

 @Override
public void onStart(){
    super.onStart();
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
    EmailPref=prefs.getString("EmailPref", EmailPref);
    if(EmailPref!=null){

        final Firebase ref = new Firebase(constants.FIREBASE_URL+"rootssahaj/authGplus");


        FirebaseRecyclerAdapter<FriendsData,FriendsViewHolder> adapter=new FirebaseRecyclerAdapter<FriendsData, FriendsViewHolder>(
                         FriendsData.class,
                         R.layout.chat_view_list,
                          FriendsViewHolder.class,
                         ref

                    ) {
            @TargetApi(Build.VERSION_CODES.KITKAT)
            @Override
            protected void populateViewHolder(FriendsViewHolder friendsViewHolder, FriendsData s, int position) {
                String key = this.getRef(position).getKey();
                Log.e("SahajLOG", "String Keyyy " + key + " n EmailPref" + EmailPref);

                if (!Objects.equals(key, EmailPref)) {
                    friendsViewHolder.mName.setText(s.getUserNAME());
                    Picasso.with(context).load(s.getPicurl()).transform(new CircleTransform()).into(friendsViewHolder.mImageProfile);


                    String keylocal = key;
                    Log.e("pavan", "Populate AddF key" + keylocal+" " + position);
                    SharedPreferences prefs …

我最近在一个项目中使用了 Google Flutter。并且想知道我们是否可以在小部件动画中应用运动模糊。它只是使动画更加逼真和舒缓。我找不到任何可用的资源。

有没有人试过？

Firebase目前已推出Firebase功能以添加服务器端代码

Firebase功能

我想知道当数据库发生一些变化时,是否可以通过这些函数调用FCM通知.