我正在创建一个Android应用程序，用户登录并输入食物点击添加的名称并将其添加到他们的冰箱。我有登录工作，我有添加，编辑，删除功能。我不确定如何确保添加的数据仅添加到登录用户冰箱。 有人可以帮忙吗？
添加食物代码：
public class addFood extends AppCompatActivity {
//we will use these constants later to pass the artist name and id to another activity
public static final String FOOD_NAME = "net.simplifiedcoding.firebasedatabaseexample.artistname";
public static final String FOOD_ID = "net.simplifiedcoding.firebasedatabaseexample.artistid";
//view objects
EditText editTextName;
Spinner spinnerCategory;
Button buttonAddFood;
ListView listViewFoods;
Button buttonScan;
Button buttonSearch;
//a list to store all the foods from firebase database
List<Food> foods;
//our database reference object
DatabaseReference databaseFoods;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_food);
//getting the reference of artists node
databaseFoods = FirebaseDatabase.getInstance().getReference("foods");
//getting views
editTextName = (EditText) findViewById(R.id.editTextName);
spinnerCategory = (Spinner) findViewById(R.id.spinnerCategories);
listViewFoods = (ListView) findViewById(R.id.listViewFoods);
buttonScan = (Button) findViewById(R.id.buttonScan);
buttonSearch = (Button) findViewById(R.id.buttonSearch);
buttonAddFood = (Button) findViewById(R.id.buttonAddFood);
//list to store artists
foods = new ArrayList<>();
//adding an onclicklistener to button
buttonAddFood.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//calling the method addArtist()
//the method is defined below
//this method is actually performing the write operation
addFood();
}
});
buttonScan.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(addFood.this, BarcodeDetect.class);
//starting the activity with intent
startActivity(intent);
}
});
buttonSearch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(addFood.this, SearchBar.class);
//starting the activity with intent
startActivity(intent);
}
});
//attaching listener to listview
listViewFoods.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
//getting the selected artist
Food food = foods.get(i);
//creating an intent
Intent intent = new Intent(getApplicationContext(), nutritionalInfo.class);
//putting artist name and id to intent
intent.putExtra(FOOD_ID, food.getFoodId());
intent.putExtra(FOOD_NAME, food.getFoodName());
//starting the activity with intent
startActivity(intent);
}
});
listViewFoods.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l) {
Food food = foods.get(i);
showUpdateDeleteDialog(food.getFoodId(), food.getFoodName());
return true;
}
});
}
protected void onStart() {
super.onStart();
//attaching value event listener
databaseFoods.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
//clearing the previous artist list
foods.clear();
//iterating through all the nodes
for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
//getting artist
Food food = postSnapshot.getValue(Food.class);
//adding artist to the list
foods.add(food);
}
//creating adapter
FoodList foodAdapter = new FoodList(addFood.this, foods);
//attaching adapter to the listview
listViewFoods.setAdapter(foodAdapter);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
/*
* This method is saving a new artist to the
* Firebase Realtime Database
* */
private void addFood() {
//getting the values to save
String name = editTextName.getText().toString().trim();
String category = spinnerCategory.getSelectedItem().toString();
//checking if the value is provided
if (!TextUtils.isEmpty(name)) {
//getting a unique id using push().getKey() method
//it will create a unique id and we will use it as the Primary Key for our Artist
String id = databaseFoods.push().getKey();
//creating an Artist Object
Food food = new Food(id, name, category);
//Saving the Artist
databaseFoods.child(id).setValue(food);
//setting edittext to blank again
editTextName.setText("");
//displaying a success toast
Toast.makeText(this, "food added", Toast.LENGTH_LONG).show();
} else {
//if the value is not given displaying a toast
Toast.makeText(this, "Please enter a food", Toast.LENGTH_LONG).show();
}
}
private boolean updateFood(String id, String name, String category) {
//getting the specified artist reference
DatabaseReference dR = FirebaseDatabase.getInstance().getReference("foods").child(id);
//updating artist
Food food = new Food(id, name, category);
dR.setValue(food);
Toast.makeText(getApplicationContext(), "Food Updated", Toast.LENGTH_LONG).show();
return true;
}
private void showUpdateDeleteDialog(final String foodId, String foodName) {
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
LayoutInflater inflater = getLayoutInflater();
final View dialogView = inflater.inflate(R.layout.update_dialog, null);
dialogBuilder.setView(dialogView);
final EditText editTextName = (EditText) dialogView.findViewById(R.id.editTextName);
final Spinner spinnerCategory = (Spinner) dialogView.findViewById(R.id.spinnerCategories);
final Button buttonUpdate = (Button) dialogView.findViewById(R.id.buttonUpdateFood);
final Button buttonDelete = (Button) dialogView.findViewById(R.id.buttonDeleteFood);
dialogBuilder.setTitle(foodName);
final AlertDialog b = dialogBuilder.create();
b.show();
buttonUpdate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String name = editTextName.getText().toString().trim();
String category = spinnerCategory.getSelectedItem().toString();
if (!TextUtils.isEmpty(name)) {
updateFood(foodId, name, category);
b.dismiss();
}
}
});
buttonDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
deleteFood(foodId);
b.dismiss();
}
});
}
private boolean deleteFood(String id) {
//getting the specified artist reference
DatabaseReference dR = FirebaseDatabase.getInstance().getReference("foods").child(id);
//removing artist
dR.removeValue();
//getting the tracks reference for the specified artist
DatabaseReference drNutritions = FirebaseDatabase.getInstance().getReference("nutritions").child(id);
//removing all tracks
drNutritions.removeValue();
Toast.makeText(getApplicationContext(), "Food Deleted", Toast.LENGTH_LONG).show();
return true;
}
}
数据库架构
{
"foods":{
"-L30jqWgsXDUOsTlLgEE":{
"bestBefore":"22/03/2018",
"foodCategory":"Fruit",
"foodId":"-L30jqWgsXDUOsTlLgEE",
"foodName":"Banana"
},
"-L30js70gQ2tjCBA9aCJ":{
...
},
"-L30js70gQ2tjCBA9aCJ":{
...
}
},
"nutritions":{
"-L30jqWgsXDUOsTlLgEE":{
"calories":"50",
"id":"-L30jqWgsXDUOsTlLgEE",
"rating":0
},
"-L30js70gQ2tjCBA9aCJ":{
...
},
"-L30js70gQ2tjCBA9aCJ":{
...
}
}
}
答案 0 :(得分：0)
我建议您更改结构，为每个用户提供不同的食物清单。像这样：
{
"foods":{
"user1":{
"-L30jqWgsXDUOsTlLgEE":{
"bestBefore":"22/03/2018",
"foodCategory":"Fruit",
"foodId":"-L30jqWgsXDUOsTlLgEE",
"foodName":"Banana"
},
"-L30js70gQ2tjCBA9aCJ":{
...
},
"-L30jtpi1OCPPXrhbmqP":{
...
}
},
"user2":{
"-L30js70gQ2tjCBA9aCJ":{
"bestBefore":"22/03/2018",
"foodCategory":"Fruit",
"foodId":"-L30js70gQ2tjCBA9aCJ",
"foodName":"Apple"
},
"-L30jtpi1OCPPXrhbmqP":{
...
}
}
}
}
其中“user1”和“user2”是2个不同用户的ID。您可以在addFood活动中从Firebase Auth获取此内容：
public class addFood extends AppCompatActivity {
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
...
然后在从uid方法中读取数据时使用此onCreate：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_food);
//getting the reference of artists node
databaseFoods = FirebaseDatabase.getInstance().getReference("foods").child(uid);
...
}
并且不要忘记分别更新updateFood和deleteFood方法：
private boolean updateFood(String id, String name, String category) {
//getting the specified artist reference
DatabaseReference dR = FirebaseDatabase.getInstance().getReference("foods").child(uid).child(id);
//updating artist
Food food = new Food(id, name, category);
dR.setValue(food);
Toast.makeText(getApplicationContext(), "Food Updated", Toast.LENGTH_LONG).show();
return true;
}
private boolean deleteFood(String id) {
//getting the specified artist reference
DatabaseReference dR = FirebaseDatabase.getInstance().getReference("foods").child(uid).child(id);
//removing artist
dR.removeValue();
//getting the tracks reference for the specified artist
DatabaseReference drNutritions = FirebaseDatabase.getInstance().getReference("nutritions").child(id);
//removing all tracks
drNutritions.removeValue();
Toast.makeText(getApplicationContext(), "Food Deleted", Toast.LENGTH_LONG).show();
return true;
}