In this android programming source code example, we are going to check if data exist in Android Firebase Database
You can copy and adopt this source code example to your android project without reinventing the wheel.
Below is a step by step source code to check if data exist in Android Firebase Database.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="15dp" android:background="#CACACA"> <TextView android:id="@+id/title" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="title" android:textSize="20sp" android:layout_marginTop="90dp"/> <View android:id="@+id/view1" android:layout_width="match_parent" android:layout_height="2sp" android:layout_below="@id/title" android:background="@color/colorAccent"/> <TextView android:id="@+id/body" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="body" android:textSize="30sp" android:layout_below="@id/view1"/> </RelativeLayout>
MainActivity.java
import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.widget.TextView; import android.widget.Toast; import com.google.firebase.database.DataSnapshot; import com.google.firebase.database.DatabaseError; import com.google.firebase.database.DatabaseReference; import com.google.firebase.database.FirebaseDatabase; import com.google.firebase.database.Query; import com.google.firebase.database.ValueEventListener; public class FirebaseActivity11 extends AppCompatActivity { private TextView title; private TextView body; private DatabaseReference mDatabase; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_firebase11); title = (TextView)findViewById(R.id.title); body = (TextView)findViewById(R.id.body); mDatabase = FirebaseDatabase.getInstance().getReference().child("AndroidView"); Query query = mDatabase.orderByChild("title"); query.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { if(dataSnapshot.exists()){ for(DataSnapshot readData: dataSnapshot.getChildren()){ Data data = readData.getValue(Data.class); title.setText(data.getTitle()); body.setText(data.getContent()); } }else{ Toast.makeText(FirebaseActivity11.this,"Data Empty",Toast.LENGTH_LONG).show(); } } @Override public void onCancelled(DatabaseError databaseError) { Toast.makeText(FirebaseActivity11.this,databaseError.getMessage(),Toast.LENGTH_LONG).show(); } }); } }
Data.java
app/build.gradle
implementation 'com.google.firebase:firebase-core:16.0.9' implementation 'com.google.firebase:firebase-database:17.0.0'
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