0
我想表现出一个TextView如何获得火力数据库中的TextView
package com.example.u_ahm.firebase;
enter code hereimport android.os.StrictMode;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.database.ChildEventListener;
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.GenericTypeIndicator;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
public class MainActivity extends AppCompatActivity {
private DatabaseReference mDatabase;
EditText etID, etName, etAddress, etSeats, etNumber;
Button addbtn,delbtn ,upbtn , showbtn;
TextView txt;
int id = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mDatabase = FirebaseDatabase.getInstance().getReference().child("College");
init();
}
private void init() {
etID = (EditText) findViewById(R.id.idText);
etName = (EditText) findViewById(R.id.nameText);
etAddress = (EditText) findViewById(R.id.addText);
etSeats = (EditText) findViewById(R.id.seatsText);
etNumber = (EditText) findViewById(R.id.numText);
addbtn = (Button) findViewById(R.id.insertBtn);
delbtn = (Button) findViewById(R.id.delBtn);
upbtn = (Button) findViewById(R.id.updateBtn);
showbtn = (Button) findViewById(R.id.showBtn);
addbtn.setOnClickListener(dbButtonsListener);
delbtn.setOnClickListener(dbButtonsListener);
upbtn.setOnClickListener(dbButtonsListener);
showbtn.setOnClickListener(dbButtonsListener);
txt = (TextView) findViewById(R.id.textView2);
}
private View.OnClickListener dbButtonsListener = new View.OnClickListener() {
@Override
public void onClick(final View v) {
switch (v.getId()){
case R.id.insertBtn:
String name = etName.getText().toString().trim();
String address = etAddress.getText().toString().trim();
String seats = etSeats.getText().toString().trim();
String number = etNumber.getText().toString().trim();
HashMap<String,String> map = new HashMap<String, String>();
map.put("Name",name);
map.put("Address",address);
map.put("Seats",seats);
map.put("Numbers",number);
mDatabase.child(Integer.toString(id)).setValue(map).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if(task.isComplete()){
Toast.makeText(MainActivity.this,"Data inserted",Toast.LENGTH_SHORT).show();
id++;
}
}
});
break;
case R.id.delBtn:
break;
case R.id.updateBtn:
break;
case R.id.showBtn:
mDatabase.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot snapshot : dataSnapshot.getChildren()){
College college = snapshot.getValue(College.class);
String string = txt.getText() + "\nName: " + college.getName()+ "\n Address : " + college.getAddress() +
"\n No. of Seats: " + college.getSeats() + "\n Numbers: " + college.getNumbers();
txt.setText(string);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
break;
}
}
};
}
我的数据，这是我的数据库
College
1
Address:
"Gulshan e Iqbal"
Name:
"Ideal"
Numbers:
"560"
Seats:
"150"
2
Address:
"Gulshan e Iqbal"
Name:
"Ideal"
Numbers:
"560"
Seats:
"150"
3
Address:
"Gulshan e Iqbal"
Name:
"Ideal"
Numbers:
"560"
Seats:
"150"
目前我收到此错误 com.google.firebase .database.DatabaseException：在反序列化时期望映射，但得到一个类java.util.ArrayList
请参阅https://firebase.google.com/docs/database/android/read-and-write – AlwaysConfused
请添加数据库的结构。 –