Android 如何在Firebase中更新数据?
我正在尝试更新数据库中产品的数量。每当我添加或扣除数量时,更改仅反映在我的应用程序上,而不会在Firebase中更新!任何帮助都将不胜感激 以下是应用程序的图片:Android 如何在Firebase中更新数据?,android,firebase,firebase-realtime-database,Android,Firebase,Firebase Realtime Database,我正在尝试更新数据库中产品的数量。每当我添加或扣除数量时,更改仅反映在我的应用程序上,而不会在Firebase中更新!任何帮助都将不胜感激 以下是应用程序的图片: public class Edit extends AppCompatActivity { String myKey = null; private Button removebutton, plus, minus; private int counterValue; protected void onCreate(Bundle
public class Edit extends AppCompatActivity {
String myKey = null;
private Button removebutton, plus, minus;
private int counterValue;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit);
removebutton = (Button) findViewById(R.id.item_detail_delete);
plus = (Button) findViewById(R.id.item_quantity_add);
minus = (Button) findViewById(R.id.item_quantity_remove);
final DatabaseReference database;
myKey = getIntent().getExtras().getString("value");
database = FirebaseDatabase.getInstance().getReference().child("All Barcodes");
database.child(myKey).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
TextView Barcode=(TextView) findViewById(R.id.Barcode);
TextView Pname=(TextView) findViewById(R.id.Pname);
TextView EntryDate=(TextView) findViewById(R.id.EntryDate);
TextView ExpiryDate=(TextView) findViewById(R.id.ExpiryDate);
final TextView Quantity=(TextView) findViewById(R.id.Quantity);
String barcode = (String) dataSnapshot.child("barcode").getValue();
String pname = (String) dataSnapshot.child("pname").getValue();
String date = (String) dataSnapshot.child("date").getValue();
String expiration = (String) dataSnapshot.child("expiration").getValue();
String quantity = (String) dataSnapshot.child("quantity").getValue();
Barcode.setText(barcode);
Pname.setText(pname);
EntryDate.setText(date);
ExpiryDate.setText(expiration);
Quantity.setText(quantity);
counterValue = Integer.valueOf(quantity);
plus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue ++;
Quantity.setText(String.valueOf(counterValue));
}
});
minus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue --;
Quantity.setText(String.valueOf(counterValue));
}
});
}
@Override
public void onCancelled(DatabaseError databaseError) {
System.out.println("The read failed: " + databaseError.getMessage());
}
});
removebutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
database.child(myKey).removeValue();
Intent intent = new Intent(Edit.this,Inventory.class);
startActivity(intent);
}
});
}
数据库图片:
这是我的代码:
public class Edit extends AppCompatActivity {
String myKey = null;
private Button removebutton, plus, minus;
private int counterValue;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit);
removebutton = (Button) findViewById(R.id.item_detail_delete);
plus = (Button) findViewById(R.id.item_quantity_add);
minus = (Button) findViewById(R.id.item_quantity_remove);
final DatabaseReference database;
myKey = getIntent().getExtras().getString("value");
database = FirebaseDatabase.getInstance().getReference().child("All Barcodes");
database.child(myKey).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
TextView Barcode=(TextView) findViewById(R.id.Barcode);
TextView Pname=(TextView) findViewById(R.id.Pname);
TextView EntryDate=(TextView) findViewById(R.id.EntryDate);
TextView ExpiryDate=(TextView) findViewById(R.id.ExpiryDate);
final TextView Quantity=(TextView) findViewById(R.id.Quantity);
String barcode = (String) dataSnapshot.child("barcode").getValue();
String pname = (String) dataSnapshot.child("pname").getValue();
String date = (String) dataSnapshot.child("date").getValue();
String expiration = (String) dataSnapshot.child("expiration").getValue();
String quantity = (String) dataSnapshot.child("quantity").getValue();
Barcode.setText(barcode);
Pname.setText(pname);
EntryDate.setText(date);
ExpiryDate.setText(expiration);
Quantity.setText(quantity);
counterValue = Integer.valueOf(quantity);
plus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue ++;
Quantity.setText(String.valueOf(counterValue));
}
});
minus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue --;
Quantity.setText(String.valueOf(counterValue));
}
});
}
@Override
public void onCancelled(DatabaseError databaseError) {
System.out.println("The read failed: " + databaseError.getMessage());
}
});
removebutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
database.child(myKey).removeValue();
Intent intent = new Intent(Edit.this,Inventory.class);
startActivity(intent);
}
});
}
您应该自己更新数据库中的相关字段:
plus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue++;
Quantity.setText(String.valueOf(counterValue));
database.child(myKey).child("quantity").setValue(String.valueOf(counterValue));
}
});
minus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue--;
Quantity.setText(String.valueOf(counterValue));
database.child(myKey).child("quantity").setValue(String.valueOf(counterValue));
}
});
您应该自己更新数据库中的相关字段:
plus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue++;
Quantity.setText(String.valueOf(counterValue));
database.child(myKey).child("quantity").setValue(String.valueOf(counterValue));
}
});
minus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
counterValue--;
Quantity.setText(String.valueOf(counterValue));
database.child(myKey).child("quantity").setValue(String.valueOf(counterValue));
}
});
最简单的方法是将“保持同步”设置为true,如下所示:
DatabaseReference scoresRef = FirebaseDatabase.getInstance().getReference("scores");
scoresRef.keepSynced(true);
这来自firebase文档
最简单的方法是将“保持同步”设置为true,如下所示:
DatabaseReference scoresRef = FirebaseDatabase.getInstance().getReference("scores");
scoresRef.keepSynced(true);
这来自firebase文档
谢谢你,穆罕默德!我已经尝试了更新的代码!但我认为保存在数据库中的数量定义为字符串。但是代码在我的数据库中将数量保存为整数,从而导致崩溃。java.lang.ClassCastException在这种情况下,您可以将
setValue(counterValue)
更改为setValue(String.valueOf(counterValue))
,就像我刚才在回答中所做的那样。谢谢,Mehmed!我已经尝试了更新的代码!但我认为保存在数据库中的数量定义为字符串。但是代码在我的数据库中将数量保存为整数,从而导致崩溃。java.lang.ClassCastException在这种情况下,您可以将setValue(counterValue)
更改为setValue(String.valueOf(counterValue))
。