[英]How to get specific data from ROOM database when an item is selected in Spinner in Android
我有一个学生实体,它包含学生姓名、学生手机号码。 我正在使用学生姓名添加学生记录,我在添加新记录时从微调器中选择学生姓名。 所以我的问题是当我选择学生姓名时,我想在我的微调器下方的 textview 中获取该特定学生的手机号码。
这就是我在微调器中获取所有名称的方式
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);
}
});
}
这是我的微调适配器
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++ ){
}
}
}
如何获取所选学生姓名的手机号码? 谢谢 !
简单,亲爱的,只需使用您的视图模型类对象(studentViewModel)来获取这样的实时数据实例-
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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