如何将 EditText 值从方法传递到同一 Activity 中 SQLiteOpenHelper

Question

我有一个微调器，它选择分支值并将其存储在 onItemSelected 方法的 EditText 中。但我需要将编辑文本（分支）中显示的值预先分配给同一活动中的 SqliteDatabase 插入操作方法。抱歉，我无法适当地提出问题。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();            }        });我需要将 Editext 值从branch.setText(text2);上面String branch= _txtbranch.getText().toString();定义的传递到public void onclick. 但它说不能解析符号branch.getText().toString; 因为它是在另一个函数中声明的。如果我在全局范围内声明它，则该getItemSlelected方法会显示错误并且应用程序崩溃。请帮忙

Answer 1

我建议进行以下更改：-

• 将 spinner、adapter 和 _txtbranch 声明为类变量

• 设置视图（spinner 和 _txtbranch）以及其他视图

• 可以选择不覆盖 onItemSelected 或 onNothingSelected，而是在按钮的 onclick 中检索所选项目（因此不需要分支 EditText）。

以下代码包含上述内容，但请参阅注释：-

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));

    }

}

请注意，以上是原则上的代码，尚未运行或测试，因此包含一些错误。