Question

我之前提出的问题get the value from a method in another class可以理解，因为它的重复，但我仍然无法找到解决问题的方法。如果有人帮忙，我将不胜感激。我进步了一点，但这还不够。首先，我目前的代码：

MainActivity.java

public class MainActivity extends AppCompatActivity
            implements CalFragment.OnDateSelected{

    private TextView mTextMessage;
    String date = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault()).format(new Date());

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.navigation_home:
                    mTextMessage.setText(R.string.menu_home);
                    return true;
                case R.id.navigation_dashboard:
                    //mTextMessage.setText(date);
                    showDateDialog();
                    mTextMessage.setText(date);
                    return true;
                case R.id.navigation_notifications:
                    mTextMessage.setText(R.string.menu_location);
                    return true;
            }
            return false;
        }
    };


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

        mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
    }

    public void showDateDialog() {
    DialogFragment CalFragment = new CalFragment();
    CalFragment.show(getSupportFragmentManager(), "timePicker");
    //date = "Hello";
    }
}

和

CalFragment.java

public class CalFragment extends DialogFragment
        implements DatePickerDialog.OnDateSetListener {
    OnDateSelected mcallback;
    public interface OnDateSelected {
        public void NewStrDate(String strDate);
    }
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current date as the default date in the picker
        final Calendar c = Calendar.getInstance();
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DAY_OF_MONTH);

        // Create a new instance of DatePickerDialog and return it
        return new DatePickerDialog(getActivity(), this, year, month, day);
    }

    public void onDateSet(DatePicker view, int year, int month, int day) {
        // Do something with the date chosen by the user
        SimpleDateFormat dateFormatter = new SimpleDateFormat("MM-dd-yyyy");
        Date d = new Date(year, month, day);
        String strDate = dateFormatter.format(d);
    }
}

我想提供从CalFragment到ShowDate对话的日期，但它不起作用。在目前的状态下，它显示implements中的MainActivity声明是错误的。我正在阅读一些java教程，但它只是我的第二天。所以请多多帮助。

从其他课程重新获得价值

0 个答案: