Java Android微调器不显示所选文本
我将数据从firestore数据库拉入ArrayList,然后将这些对象加载到微调器中。当我打开微调器进行选择时,所有对象都会正确显示,但当从微调器中选择对象时,微调器将保持空白且不显示任何文本。我已经尝试添加Java Android微调器不显示所选文本,java,android,firebase,spinner,Java,Android,Firebase,Spinner,我将数据从firestore数据库拉入ArrayList,然后将这些对象加载到微调器中。当我打开微调器进行选择时,所有对象都会正确显示,但当从微调器中选择对象时,微调器将保持空白且不显示任何文本。我已经尝试添加adapter.notifyDataSetChanged()
adapter.notifyDataSetChanged()我也尝试过改变文本的颜色,正如我在别处看到的那样,但这两种解决方案都不起作用
这是我的java文件:
public class AdminEditor extends AppCompatActivity {
FirebaseFirestore db;
CollectionReference usersRef;
ArrayList<UserItem> users;
Spinner spinnerUser;
Button btnGetData;
TextView txtTest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_admin_editor);
//Set up FireStore and references
db = FirebaseFirestore.getInstance();
usersRef = db.collection("users");
//Set up resources
txtTest = findViewById(R.id.txtTest);
spinnerUser = findViewById(R.id.spinnerUser);
btnGetData = findViewById(R.id.btnGetData);
users = new ArrayList<UserItem>();
loadUsers();
updateSpinner();
}
public void loadUsers() {
usersRef.get()//Get entire users collection
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
@Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
for (QueryDocumentSnapshot documentSnapshot : queryDocumentSnapshots) {
users.add((UserItem)documentSnapshot.toObject(UserItem.class));//Add each user from the collection to the arraylist
}
}
});
}
//To fill spinners with data
public void updateSpinner() {
ArrayAdapter<UserItem> adapter = new ArrayAdapter<UserItem>(this, android.R.layout.simple_spinner_item, users);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerUser.setAdapter(adapter);
spinnerUser.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
UserItem user = (UserItem) parent.getSelectedItem();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
}
公共类AdminEditor扩展AppCompative活动{
FirebaseFirestore数据库;
收集参考用户sref;
ArrayList用户;
纺纱机;
按钮btnGetData;
TextView-txtTest;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u admin\u编辑器);
//设置FireStore和引用
db=FirebaseFirestore.getInstance();
usersRef=db.collection(“用户”);
//建立资源
txtTest=findViewById(R.id.txtTest);
spinnerUser=findViewById(R.id.spinnerUser);
btnGetData=findViewById(R.id.btnGetData);
users=newarraylist();
loadUsers();
updateSpiner();
}
公共void loadUsers(){
usersRef.get()//获取整个用户集合
.addOnSuccessListener(新的OnSuccessListener(){
@凌驾
成功时公共无效(QuerySnapshot QueryDocumentSnapshot){
用于(QueryDocumentSnapshot文档快照:QueryDocumentSnapshot){
users.add((UserItem)documentSnapshot.toObject(UserItem.class));//将集合中的每个用户添加到arraylist
}
}
});
}
//用数据填充微调器
public void updateSpiner(){
ArrayAdapter=新的ArrayAdapter(这是android.R.layout.simple\u微调器\u项,用户);
setDropDownViewResource(android.R.layout.simple\u微调器\u下拉菜单\u项);
喷丝头用户设置适配器(适配器);
spinnerUser.setOnItemSelectedListener(新AdapterView.OnItemSelectedListener()){
@凌驾
已选择公共视图(AdapterView父视图、视图视图、整型位置、长id){
UserItem user=(UserItem)parent.getSelectedItem();
}
@凌驾
未选择公共无效(AdapterView父级){
}
});
}
}
以下是xml文件:
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".AdminEditor">
<Spinner
android:id="@+id/spinnerUser"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="128dp"
android:spinnerMode="dropdown"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/btnGetData"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="28dp"
android:text="Get Data"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/spinnerUser" />
<TextView
android:id="@+id/txtTest"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/btnGetData" />
</androidx.constraintlayout.widget.ConstraintLayout>```
Thanks for your help
```
谢谢你的帮助
只要用户完全从Firebase接收到,就更新您的微调器,因此将对UpdateSpiner()
的调用转移到usersRef.get().addOnSuccessListener
中,并将其从onCreate()
方法中删除
public void loadUsers() {
usersRef.get()//Get entire users collection
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
@Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
for (QueryDocumentSnapshot documentSnapshot : queryDocumentSnapshots) {
users.add((UserItem)documentSnapshot.toObject(UserItem.class));//Add each user from the collection to the arraylist
}
updateSpinner();
}
});
public void loadUsers(){
usersRef.get()//获取整个用户集合
.addOnSuccessListener(新的OnSuccessListener(){
@凌驾
成功时公共无效(QuerySnapshot QueryDocumentSnapshot){
用于(QueryDocumentSnapshot文档快照:QueryDocumentSnapshot){
users.add((UserItem)documentSnapshot.toObject(UserItem.class));//将集合中的每个用户添加到arraylist
}
updateSpiner();
}
});
只要用户完全从Firebase接收到,就更新您的微调器,因此将对UpdateSpiner()
的调用转移到usersRef.get().addOnSuccessListener
中,并将其从onCreate()
方法中删除
public void loadUsers() {
usersRef.get()//Get entire users collection
.addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
@Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
for (QueryDocumentSnapshot documentSnapshot : queryDocumentSnapshots) {
users.add((UserItem)documentSnapshot.toObject(UserItem.class));//Add each user from the collection to the arraylist
}
updateSpinner();
}
});
public void loadUsers(){
usersRef.get()//获取整个用户集合
.addOnSuccessListener(新的OnSuccessListener(){
@凌驾
成功时公共无效(QuerySnapshot QueryDocumentSnapshot){
用于(QueryDocumentSnapshot文档快照:QueryDocumentSnapshot){
users.add((UserItem)documentSnapshot.toObject(UserItem.class));//将集合中的每个用户添加到arraylist
}
updateSpiner();
}
});
谢谢你的帮助,效果很好。真不敢相信我被困了2个小时。谢谢你的帮助,效果很好。真不敢相信我被困了2个小时。