unfortunately I have a problem which I can not solve. That's why I need your help. When a new user is added and the userActivity (KontakteActivity ) is open, the app crashes sometimes. Please let me know if I have forgotten something that is helpful for the problem solution
Here is the code of the userActivity:
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.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;
import com.bumptech.glide.Glide;
import com.bumptech.glide.load.engine.DiskCacheStrategy;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
public class KontakteActivity extends AppCompatActivity {
TextView kontakt_name,kontakt_email;
RecyclerView recyclerView;
FirebaseDatabase firebaseDatabase;
DatabaseReference mDatabaseReference;
public FirebaseRecyclerAdapter<FirebaseDB_helper,Kontakte_Viewholder> mFirebaseAdapter;
ProgressBar progressBar;
LinearLayoutManager linearLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_kontakte);
//DB
firebaseDatabase = FirebaseDatabase.getInstance();
mDatabaseReference = firebaseDatabase.getReference("Users");
mDatabaseReference.keepSynced(true);
//Views
progressBar = (ProgressBar)findViewById(R.id.progressBar_act_kontakte);
recyclerView = (RecyclerView)findViewById(R.id.recylerView_kontakte_act_kontakte);
linearLayoutManager = new LinearLayoutManager(KontakteActivity.this);
recyclerView.setLayoutManager(linearLayoutManager);
}
@Override
protected void onStart() {
super.onStart();
progressBar.setVisibility(ProgressBar.VISIBLE);
mFirebaseAdapter = new FirebaseRecyclerAdapter<FirebaseDB_helper, Kontakte_Viewholder>
(FirebaseDB_helper.class, R.layout.kontakte_card_view, Kontakte_Viewholder.class, mDatabaseReference) {
public void populateViewHolder(final Kontakte_Viewholder viewholder , FirebaseDB_helper model, final int position)
{
progressBar.setVisibility(View.INVISIBLE);
viewholder.Kontakt_Name(model.getName());
viewholder.Kontakt_Image(model.getImage_Url());
if (model.getEmail().equals(MainActivity.User_email))
{
viewholder.Layout_hide();
}else {
viewholder.Kontakt_Email(model.getEmail());
}
}
};
mFirebaseAdapter.notifyDataSetChanged();
recyclerView.setAdapter(mFirebaseAdapter);
}
// /*
public static class Kontakte_Viewholder extends RecyclerView.ViewHolder{
private final TextView kontakt_name,kontakt_email;
private final ImageView kontakt_image;
private final LinearLayout layout;
final LinearLayout.LayoutParams params;
public Kontakte_Viewholder(final View itemView) {
super(itemView);
kontakt_name=(TextView)itemView.findViewById(R.id.txt_name_kontakt_card);
kontakt_email=(TextView)itemView.findViewById(R.id.txtView_email_kontakt_card);
kontakt_image=(ImageView)itemView.findViewById(R.id.imageView_kontakt_card);
layout = (LinearLayout)itemView.findViewById(R.id.linearlayout_kontakt_card_view); //Probleeeeeem
params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);//erforderlich um ein LinearLayout anzupassen
}
private void Kontakt_Name(String name)
{
kontakt_name.setText(name);
}
private void Layout_hide()
{
params.height=0;
layout.setLayoutParams(params);
}
private void Kontakt_Email (String email)
{
kontakt_email.setText(email);
}
private void Kontakt_Image (String Url)
{
if (!Url.equals("Null")){
Glide.with(itemView.getContext())
.load(Url)
.crossFade()
.thumbnail(0.5f)
.placeholder(R.drawable.loading)
.diskCacheStrategy(DiskCacheStrategy.ALL)
.into(kontakt_image);
}
}
}//*/
}
Here is the crash report of Android Studio
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.zare.ma_firechat, PID: 9510
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at com.example.zare.ma_firechat.KontakteActivity$Kontakte_Viewholder.Kontakt_Image(KontakteActivity.java:129)
at com.example.zare.ma_firechat.KontakteActivity$Kontakte_Viewholder.access$100(KontakteActivity.java:94)
at com.example.zare.ma_firechat.KontakteActivity$1.populateViewHolder(KontakteActivity.java:74)
at com.example.zare.ma_firechat.KontakteActivity$1.populateViewHolder(KontakteActivity.java:61)
at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:184)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6356)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6389)
at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5335)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5598)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5440)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5436)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2224)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1551)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1511)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:595)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3583)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3025)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
at android.view.View.measure(View.java:19734)
at android.support.constraint.ConstraintLayout.onMeasure(ConstraintLayout.java:1028)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:19734)
