无法在此日期和月份方法中正确获取 return - Android Studio

Question

我一直在摆弄我创建的这个方法，但无法让它发挥作用。
我得到的字符串无法转换为 int 或需要一个 return，但是我无法在 return 语句中输入 monthString 变量，因为它超出了序数方法的范围并且不能找到变量。

import android.app.DatePickerDialog;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;

import java.util.Calendar;

/**
 * Created by avi31 on 31/01/2018.
 */


import android.app.DatePickerDialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.DatePicker;
import android.widget.TextView;
import android.widget.Toast;

import java.util.Calendar;

public class ProfileSettings extends AppCompatActivity {

    private static final String TAG = "Profile_Settings";


    private DatePickerDialog.OnDateSetListener mDateSetListener;
    private TextView mDisplayDate;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_settings);
        mDisplayDate = (TextView) findViewById(R.id.tvDate);

        mDisplayDate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Calendar cal = Calendar.getInstance();
                int year = cal.get(Calendar.YEAR);
                int month = cal.get(Calendar.MONTH);
                int day = cal.get(Calendar.DAY_OF_MONTH);

                DatePickerDialog dialog = new DatePickerDialog(
                        ProfileSettings.this,
                        android.R.style.Theme_Holo_Light_Panel,
                        mDateSetListener,
                        year, month, day);
                dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                dialog.show();
            }
        });


        mDateSetListener = new DatePickerDialog.OnDateSetListener() {
            @Override
            public void onDateSet(DatePicker datePicker, int year, int month, int day) {
                month = month + 1;
                Log.w(TAG, "Date of Birth: " + day + "/" + month + "/" + year);

                String date = day + "/" + month + "/" + year;
                mDisplayDate.setText(date);
                Toast.makeText(ProfileSettings.this, date, Toast.LENGTH_LONG).show();
                ordinal(day, month, year);
            }


            String ordinal(int day, int month, int year) {
                String[] day1 = new String[]{"th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th"};

                String monthString = "Default";

                switch (day % 100) {
                    case 11:
                    case 12:
                    case 13:

                        switch (month) {
                            case 1:  monthString = "January";
                                break;
                            case 2:  monthString = "February";
                                break;
                            case 3:  monthString = "March";
                                break;
                            case 4:  monthString = "April";
                                break;
                            case 5:  monthString = "May";
                                break;
                            case 6:  monthString = "June";
                                break;
                            case 7:  monthString = "July";
                                break;
                            case 8:  monthString = "August";
                                break;
                            case 9:  monthString = "September";
                                break;
                            case 10: monthString = "October";
                                break;
                            case 11: monthString = "November";
                                break;
                            case 12: monthString = "December";
                                break;



                        }



                }
                Log.w(TAG, day + "" + day1[day % 10] + " " + monthString + " " + year);
                return day + monthString + year;
            }


            public void buttonClicked(View view) {
                if (view.getId() == R.id.btn_exit) {
                    finish();
                    Log.w(TAG, "Exit back to previous activity");
                }
            }
        };


    }

Answer 1

您正在 case13 中声明变量 month 字符串，就在第二个 switch 语句之前，移动并初始化第一个 switch 语句之外的 monthString 变量。

Answer 2

String monthString; 是在 switch 语句中定义的，因此范围有限。把它移到外面就可以了。

将它移到您定义 day1 数组的行之后。

Answer 3

String ordinal(int day, int month, int year) {
        String[] day1 = new String[]{"th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th"};

        String monthString = ""; //declare here

        switch (day % 100) {
            case 11:
            case 12:
            case 13:
                Log.w(TAG, day + "th");

                switch (month) {
                    case 1:  monthString = "January";
                        break;
                    case 2:  monthString = "February";
                        break;
                    case 3:  monthString = "March";
                        break;
                    case 4:  monthString = "April";
                        break;
                    case 5:  monthString = "May";
                        break;
                    case 6:  monthString = "June";
                        break;
                    case 7:  monthString = "July";
                        break;
                    case 8:  monthString = "August";
                        break;
                    case 9:  monthString = "September";
                        break;
                    case 10: monthString = "October";
                        break;
                    case 11: monthString = "November";
                        break;
                    case 12: monthString = "December";
                        break;
                }
                break; //you're missing this break after the case
        }
        return day + monthString;
    }

无法在此日期和月份方法中正确获取 return - Android Studio

Cannot get return right in this date and month method - Android Studio

java

android

switch-statement

android-date

ordinal