[英]How to get specific data from ROOM database when an item is selected in Spinner in Android
我有一個學生實體,它包含學生姓名、學生手機號碼。 我正在使用學生姓名添加學生記錄,我在添加新記錄時從微調器中選擇學生姓名。 所以我的問題是當我選擇學生姓名時,我想在我的微調器下方的 textview 中獲取該特定學生的手機號碼。
這就是我在微調器中獲取所有名稱的方式
private void loadSpinnerData() {
studentViewModel = ViewModelProviders.of(this).get(StudentViewModel.class);
studentViewModel.getAllStudents().observe(this, new Observer<List<Student>>() {
@Override
public void onChanged(List<Student> students) {
String[] nameLists = new String[students.size()];
for (i = 0; i < students.size(); i++) {
nameLists[i] = students.get(i).getStudentName() + " " + students.get(i).getStudentFatherName() +
" " + students.get(i).getStudentSurname();
}
ArrayAdapter<String> studentNames = new ArrayAdapter<>(getApplicationContext(), android.R.layout.simple_spinner_dropdown_item, nameLists);
studentNames.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
selectStudentName.setAdapter(studentNames);
}
});
}
這是我的微調適配器
selectStudentName.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(final AdapterView<?> adapterView, View view, final int position, long l) {
if ( position == -1 ) {
Toast.makeText(AddRecord.this, "No record is selected", Toast.LENGTH_SHORT).show();
} else {
String name = adapterView.getItemAtPosition(position).toString();
Toast.makeText(AddRecord.this, name + " is selected", Toast.LENGTH_SHORT).show();
for (int i = 0; i < adapterView.getCount(); i++ ){
}
}
}
如何獲取所選學生姓名的手機號碼? 謝謝 !
簡單,親愛的,只需使用您的視圖模型類對象(studentViewModel)來獲取這樣的實時數據實例-
selectStudentName.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(final AdapterView<?> adapterView, View view, final int position, long l) {
if ( position == -1 ) {
Toast.makeText(AddRecord.this, "No record is selected", Toast.LENGTH_SHORT).show();
} else {
String studentMobileNumber = studentViewModel.getAllStudents().getValue().get(position).getMobileNumber()
}
}
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