java - 如何将 EditText 值从方法传递到同一 Activity 中 SQLiteOpenHelper 类的 Insert 函数？

Question

我有一个微调器，它在 onItemSelected 方法中选择分支值并存储在 EditText 中。但是我需要将编辑文本（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，我无法恰当地提出问题。

注册.java

public 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();
            }
        });

        Spinner spinner=findViewById(R.id.semester);

        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.semester,android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);
    }

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);

    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
        String text=adapterView.getItemAtPosition(i).toString();
        EditText branch= (EditText)findViewById(R.id.branch);
        String text2=adapterView.getSelectedItem().toString();
        branch.setText(text2);
        Toast.makeText(adapterView.getContext(),text,Toast.LENGTH_SHORT).show();

    }

    @Override
    public void onNothingSelected(AdapterView<?> adapterView) {

    }


    public void open_login(View view){
        startActivity(new Intent(getApplicationContext(),login.class));
    }
}

我需要将 Editext 值从branch.setText(text2);上面String branch= _txtbranch.getText().toString();定义的public void onclick. 但它说不能

解析符号 branch.getText().toString; 因为它在另一个函数中声明。

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。

标签： javaandroid-studioandroid-sqlite

Answer 1

我建议进行以下更改：-

• 将微调器、适配器和 _txtbranch 声明为类变量
• 将视图（微调器和 _txtbranch）与其他视图一起设置
• 可选地，没有对 onItemSelected 或 onNothingSelected 的覆盖，而是在按钮的 onclick 中检索所选项目（因此不需要分支 EditText）。

以下代码包括上述内容，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，以上是原则代码，尚未运行或测试，因此包含一些错误。