Question

这里我试图在XML和JAVA中使用Spinner。具体来说，我做了一个程序，显示关于茶，风格，flava，顶部选择的Toast。在进行此步骤之前，我确实检查了该程序的另一个更简单版本，此时一切运行顺利。然而，它是如此令人困惑。事实上，我没有经验足以找出问题所在。请帮助一个新手，代码可能会有点长，我会非常，非常感谢

package com.example.second_spinner;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast; 

public class Second_Spinner extends Activity {
    private String tea_message = "";
    private String style_message = "";
    private String flava_message = "";
    private String moreLove_message = "";
    private String message = getString(R.string.message);
    private int maximum_flava = 4;
    private ArrayList<String> alreadyFlava = new ArrayList<String>();
    private ArrayList<String> alreadyLove = new ArrayList<String>();


    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);;
        setContentView(R.layout.activity_second__spinner);

        Spinner spinner1 = (Spinner) findViewById(R.id.spinner1);
        Spinner spinner2 = (Spinner) findViewById(R.id.spinner2);

        spinner1.setOnItemSelectedListener(new MilkTea());
        spinner2.setOnItemSelectedListener(new MilkTea());

        Spinner spinner3 = (Spinner) findViewById(R.id.spinner3);
        Spinner spinner4 = (Spinner) findViewById(R.id.spinner4);

        List<String> flava = getFlava();
        ArrayAdapter<String> spinnerAdapter1 = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,flava);
        spinnerAdapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner3.setAdapter(spinnerAdapter1);
        spinner3.setOnItemSelectedListener(new MilkTea());

        List<String> moreLove = getMoreLove();
        ArrayAdapter<String> spinnerAdapter2 = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,moreLove);
        spinnerAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner4.setAdapter(spinnerAdapter2);
        spinner4.setOnItemSelectedListener(new MilkTea());
    }



    private class MilkTea implements OnItemSelectedListener {
        private boolean isFirst;

        public void onItemSelected(AdapterView<?> spinner, View selectedView, int selectedIndex, long id) {
            if (isFirst == false) {
                isFirst = true;
            }
            else {
                switch (selectedView.getId()) {

                    case (R.id.spinner1) :
                        tea_message = spinner.getItemAtPosition(selectedIndex).toString();
                        break;

                    case (R.id.spinner2) :
                        style_message = spinner.getItemAtPosition(selectedIndex).toString();
                        break;

                    case (R.id.spinner3) :
                        if (maximum_flava > 0) {
                            if (alreadyFlava.isEmpty()) {
                                flava_message = spinner.getItemAtPosition(selectedIndex).toString();
                                alreadyFlava.add(flava_message);
                                maximum_flava--;
                            }
                            else {
                                boolean sign = true;
                                String temp = spinner.getItemAtPosition(selectedIndex).toString();
                                for (int i = 0; i < alreadyFlava.size(); i++)
                                    if (temp.equals(alreadyFlava.get(i))) {
                                        sign = false;
                                        break;
                                    }
                                if (sign == true) {
                                    flava_message += ","+temp;
                                    alreadyFlava.add(flava_message);
                                    maximum_flava--;
                                }
                            }
                        }   
                        break;

                    case (R.id.spinner4) :
                        if (alreadyLove.isEmpty()) {
                            moreLove_message = spinner.getItemAtPosition(selectedIndex).toString();
                            alreadyFlava.add(flava_message);
                        }
                        else {
                            boolean sign = true;
                            String temp = spinner.getItemAtPosition(selectedIndex).toString();
                            for (int i = 0; i < alreadyLove.size(); i++)
                                if (temp.equals(alreadyLove.get(i))) {
                                    sign = false;
                                    break;
                                }
                            if (sign == true) {
                                moreLove_message += ","+temp;
                                alreadyLove.add(moreLove_message);
                            }
                        }
                        break;
                }
                message = String.format(message, tea_message, style_message, flava_message, moreLove_message);
                Toast.makeText(getBaseContext(), message, Toast.LENGTH_SHORT).show();
            }
        }

        public void onNothingSelected(AdapterView<?> spinner) {

        }
    }



    private List<String> getFlava() {
        String[] flava = {
                "No, I'm good", "Honeydew", "Blood Orange", "Red Guava", "Kumquat", "Lychee", "Longan", "Blackberry",
                "Pineapple", "Mango", "Passion Fruit", "Taro", "Strawberry", "Coconut"
        };
        List<String> flava_list = Arrays.asList(flava);
        return flava_list;
    }



    private List<String> getMoreLove() {
        String[] moreLove = {
                "Not Today","Aloe Vera","Black Pearls", "Coffee Jelly","White Pearls","Grass Jelly","Passion Jelly",
                "Coconut Jelly","Lychee Jelly","Strawberry Jelly","Manga Jelly","Manga Stars"
        };
        List<String> moreLove_list = Arrays.asList(moreLove);
        return moreLove_list;
    }


}

Answer 1

private String message = getString(R.string.message);

您过早地访问资源。您无法在活动构建时访问资源，例如初始化成员变量时。您需要等到活动生命周期中的onCreate()。将getString()移到那里。

通常，要了解出错的地方，请参阅logcat中的异常堆栈跟踪。也包括在你的问题中。见Unfortunately MyApp has stopped. How can I solve this?

在这种情况下我的代码有什么问题导致＆＃34;程序意外停止＆＃34;？

1 个答案: