Question

我想从单选按钮获取文本但我收到错误

java.lang.NullPointerException：尝试调用虚方法＆＃39; int android.widget.RadioGroup.getCheckedRadioButtonId（）＆＃39;在空对象引用上

请告诉我如何从单选按钮获取文本并删除def reduce[T[_]: Traversable, O: Monoid]: T[O] => O = { to => // This forces the compiler to pass in the correct implicits val accumulate_ = accumulate[T, O, O] accumulate_(a => a)(to) }。

这是代码

NullPointerException

这里是logcat

public class BookActivity extends AppCompatActivity  {

    EditText editText4;
    EditText editText6;
    RadioGroup time;
    Button book;
    RadioButton radioButton;

    //RadioButton radioButton, radioButton2, radioButton3, radioButton4, radioButton5, radioButton6, radioButton7, radioButton8, radioButton9;
    Context context = this;
    UserDbHelper userDbHelper;
    SQLiteDatabase sqLiteDatabase;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.book);

        editText4 = (EditText) findViewById(R.id.editText4);
        editText6 = (EditText) findViewById(R.id.editText6);
        time=(RadioGroup)findViewById(R.id.time);
        book=(Button)findViewById(R.id.book);

        addListenerOnButton();
    }


    public void addListenerOnButton() {
        time = (RadioGroup) findViewById(R.id.radio);
        book = (Button) findViewById(R.id.book);

        book.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                // get selected radio button from radioGroup
                int selectedId = time.getCheckedRadioButtonId();

                // find the radiobutton by returned id
                radioButton = (RadioButton) findViewById(selectedId);
                if (radioButton != null) {
                    String pname = editText4.getText().toString();
                    String rtime = radioButton.getText().toString();

                    userDbHelper = new UserDbHelper(context);
                    sqLiteDatabase = userDbHelper.getWritableDatabase();
                    userDbHelper.addInformations(pname, rtime, sqLiteDatabase);
                    Toast.makeText(BookActivity.this, "Data Saved", Toast.LENGTH_LONG).show();
                    userDbHelper.close();
                }

                //Toast.makeText(BookActivity.this,radioButton.getText(), Toast.LENGTH_SHORT).show();
            }
        });
    }
}

Answer 1

问题可能出在RadioGroup Time Varaible上因为首先将id设置为R.id.time并在addListener函数中将id更改为R.id.radio.check，即在xml中正确的RadioGroup Id。当然有这个帮助。谢谢

我想从单选按钮获取文本并将其存储在sqlite数据库中但我收到错误

1 个答案: