我有一個微調器，它選擇分支值并將其存儲在 onItemSelected 方法的 EditText 中。但我需要將編輯文本（分支）中顯示的值預先分配給同一活動中的 SqliteDatabase 插入操作方法。抱歉，我無法適當地提出問題。register.javapublic class register extends AppCompatActivity implements AdapterView.OnItemSelectedListener { SQLiteOpenHelper openHelper; SQLiteDatabase db; Button _btnsignup; EditText _txtFname, _txtLname, _txtpass, _txtemail, _txtrollno; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.register); openHelper=new DatabaseHelper(this); _btnsignup= findViewById(R.id.btn_signup); _txtFname=findViewById(R.id.fname); _txtLname=findViewById(R.id.lname); _txtpass=findViewById(R.id.password); _txtemail=findViewById(R.id.email); _txtrollno=findViewById(R.id.rollno); _btnsignup.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { db=openHelper.getWritableDatabase(); String fname=_txtFname.getText().toString(); String Lname= _txtLname.getText().toString(); String pwd= _txtpass.getText().toString(); String email= _txtemail.getText().toString(); String rollno= _txtrollno.getText().toString(); insertdata(Fname, Lname, pwd,email,rollno); Toast.makeText(getApplicationContext(), "Registered Succesfully", Toast.LENGTH_LONG).show(); } });我需要將 Editext 值從branch.setText(text2);上面String branch= _txtbranch.getText().toString();定義的傳遞到public void onclick. 但它說不能解析符號branch.getText().toString; 因為它是在另一個函數中聲明的。如果我在全局范圍內聲明它，則該getItemSlelected方法會顯示錯誤并且應用程序崩潰。請幫忙
1 回答
慕俠2389804
TA貢獻1719條經驗 獲得超6個贊
我建議進行以下更改：-
將 spinner、adapter 和 _txtbranch 聲明為類變量
設置視圖（spinner 和 _txtbranch）以及其他視圖
可以選擇不覆蓋 onItemSelected 或 onNothingSelected，而是在按鈕的 onclick 中檢索所選項目（因此不需要分支 EditText）。
以下代碼包含上述內容，但請參閱注釋：-
public class register extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
SQLiteOpenHelper openHelper;
SQLiteDatabase db;
Button _btnsignup;
Spinner spinner; //<<<<<<<<<< DECLARED HERE
ArrayAdapter<CharSequence> adapter; //<<<<<<<<<< DECLARED HERE
EditText _txtFname, _txtLname, _txtpass, _txtemail, _txtrollno, _txtbranch /* <<<<<<<<<< CHANGED to add _txtbranch>>>>>>>> */;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.register);
openHelper=new DatabaseHelper(this);
_btnsignup= findViewById(R.id.btn_signup);
_txtFname=findViewById(R.id.fname);
_txtLname=findViewById(R.id.lname);
_txtpass=findViewById(R.id.password);
_txtemail=findViewById(R.id.email);
_txtrollno=findViewById(R.id.rollno);
_txtbranch=findViewById(R.id.branch); /* <<<<<<<<<< ADDED >>>>>>>>>> Alternately not needed if getting item directly from spinner*/
spinner=findViewById(R.id.semester); /*<<<<<<<<<<< MOVED TO HERE spinner defined as a class variable */
_btnsignup.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
db=openHelper.getWritableDatabase();
String fname=_txtFname.getText().toString();
String Lname= _txtLname.getText().toString();
String pwd= _txtpass.getText().toString();
String email= _txtemail.getText().toString();
String rollno= _txtrollno.getText().toString();
String branch = _txtbranch.getText().toString(); // code wanted BUT not needed if value obtained directly from the spinner
//String branch = spinner.getSelectedItem().toString(); // ALTERNATIVE no need _txtbranch duplicating selected value
insertdata(Fname, Lname, pwd,email,rollno);
Toast.makeText(getApplicationContext(), "Registered Succesfully", Toast.LENGTH_LONG).show();
//Toast.makeText(view.getContext(),"Registered Succesfully", Toast.LENGTH_LONG).show(); // Alternative to previous line gets the context from the view
}
});
adapter = ArrayAdapter.createFromResource(this, R.array.semester,android.R.layout.simple_spinner_item); //<<<<<<<<<< CHANGED
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(this); //<<<<<<<<<< not really needed as selected item can be retrieved directly from spinner
}
public void insertdata( String Fname, String Lname, String pwd, String email, String rollno) {
ContentValues contentValues = new ContentValues();
contentValues.put(DatabaseHelper.COL_2, Fname);
contentValues.put(DatabaseHelper.COL_3, Lname);
contentValues.put(DatabaseHelper.COL_4, pwd);
contentValues.put(DatabaseHelper.COL_5, email);
contentValues.put(DatabaseHelper.COL_6, rollno);
long id = db.insert(DatabaseHelper.TABLE_NAME, null, contentValues);
}
// Not needed if retrieving value directly from spinner
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
String text=adapterView.getItemAtPosition(i).toString();
//branch= (EditText)findViewById(R.id.branch);
String text2=adapterView.getSelectedItem().toString();
_txtbranch.setText(text2);
Toast.makeText(adapterView.getContext(),text,Toast.LENGTH_SHORT).show();
}
// Not needed if retrieving value directly from spinner
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
public void open_login(View view){
startActivity(new Intent(getApplicationContext(),login.class));
}
}
請注意，以上是原則上的代碼，尚未運行或測試，因此包含一些錯誤。
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