Question

我只是从原来的帖子中编辑了这篇帖子，因为我可以缩小问题的范围，但不想为此开篇额外的帖子。

我想要的 我有一个活动，其中我将房屋中的数据生成到数组中。然后在打开另一个活动时，应该使用数据来显示它。

我的问题 数据已正确生成，我可以在日志中看到要访问它之前生成的数据。在访问时，它仍然无法显示我的数据。

我的代码

Houses.java（我在其中生成房屋并使用下面已经给出的答案来获取我的数据）

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    ->getDefinition('scheb_two_factor.security.google_authenticator')
    ->setPublic(true);

BuyHousesActivity.java（此处应访问并显示数据）

public class Houses{

int[][] NewHouseProps = new int[20][10];
int[][] HouseProps;

public Houses(){
}

public ArrayList<Integer> getClasses()
{
    ArrayList<Integer> classes = new ArrayList<>();
    Log.d("Test","ID: "+3+" CLASS: "+NewHouseProps[3][0]);
    Log.d("Test","ID: "+4+" CLASS: "+NewHouseProps[4][0]);
    for(int id=0 ; id<=8; id++) {
        classes.add(NewHouseProps[id][0]);
        Log.d("getClasses","Classes: "+NewHouseProps[id][0]);
        Log.d("getClasses!!!!!!!!!", "List: "+classes.get(id));
    }

    return classes;
}

public void GenerateHouses(){
    Log.d("Generate Houses","!!");
    for(int id=0; id<=8; id++){
            Random r = new Random();
            int h_class, garage = 0, rooms = 0, furn = 0, balkon = 0, pool = 0;
            h_class = r.nextInt(4); //Klasse
            if(h_class == 0){
                rooms = r.nextInt(4)+1;
                balkon = r.nextInt(1);
            }else if(h_class == 1){
                rooms = r.nextInt(3)+3;
                garage = r.nextInt(1)+1;
                pool = r.nextInt(1);
                balkon = r.nextInt(2);
            }else if(h_class == 2){
                rooms = r.nextInt(3)+2;
                garage = r.nextInt(2)+2;
                pool = r.nextInt(1);
            }else if(h_class == 3){
                rooms = r.nextInt(8)+6;
                garage = r.nextInt(6)+4;
                pool = r.nextInt(1);
                balkon = r.nextInt(3);
            }
            furn = r.nextInt(1);

            int price = GenerateHousePrice(id, h_class, garage, rooms, furn, balkon, pool);
            NewHouseProps[id][0] = h_class;
            NewHouseProps[id][1] = price;
            NewHouseProps[id][2] = rooms;
            NewHouseProps[id][3] = furn;
            NewHouseProps[id][4] = balkon;
            NewHouseProps[id][5] = pool;
            NewHouseProps[id][6] = garage;
            Log.d("ID: ", Integer.toString(id));
            Log.d("CLASS: ",Integer.toString(NewHouseProps[id][0]));
            Log.d("PRICE: ", Integer.toString(NewHouseProps[id][1]));
    }

}

public int GenerateHousePrice(int id, int h_class, int garage, int rooms, int furn, int balkon, int pool){

    int price = 0, pricep = 0;
    Random r = new Random();
    if(h_class == 0){
        price = r.nextInt(150000)+50000; // 50 - 200 tausend
        price += rooms * 7500;
    }
    else if(h_class == 1){
        price = r.nextInt(165000)+85000; //85 - 250 tausend
        price += rooms * 12500;
    }
    else if(h_class == 2){
        price = r.nextInt(300000)+100000; //100 - 400 tausnd
        price += rooms * 20000;
    }
    else if(h_class == 3){
        price = r.nextInt(800000)+500000; // 500 - 1.3 Mill.
        price += rooms * 15000;
    }

    if(garage > 0){
        pricep += price*0.20;
        pricep += garage * 500;
    }
    if(furn == 1){
        pricep += price*0.25;
    }
    if(balkon > 0){
        pricep += price*0.1;
        pricep += balkon*500;
    }
    if(pool == 1){
        pricep += 20000;
    }
    price += pricep;
    return price;
}

我的日志 这些是我的日志的结果，它们与您在上面看到的位置相同： Generating Accessing

希望您能帮助我，告诉我我做错了什么和/或忘记了什么。

Answer 1

发生这种情况是因为您使用的是空列表。看。

在您的public static char[][] hashTable = { "".toCharArray(), "".toCharArray(), "abc".toCharArray(), "def".toCharArray(), "ghi".toCharArray(), "jkl".toCharArray(), "mno".toCharArray(), "pqrs".toCharArray(), "tuv".toCharArray(), "wxyz".toCharArray() };中，您致电：

FragmentBuyHouse

但是，当您实例化BuyHousesActivity bha = new BuyHousesActivity(); List<Integer> classes = bha.classes;时，它将初始化不包含任何数据的数组。看你的班级new BuyHouseActivity()

BuyHouseActivity

在实现中，您在方法List<Integer> classes = new ArrayList<>();中填充数组classes，但在安装该类时未调用该方法。这是因为在第46行出现错误。

您需要像使用Bundle一样通过参数传递数据。

解决方案2

您可以创建一个静态方法来返回类：

更改您的onCreate()：

BuyHousesActivity

您想获得像public class BuyHousesActivity extends FragmentActivity { List<Integer> classes = new ArrayList<>(); private ViewPager mPager; private PagerAdapter mPagerAdapter; @Override protected void onCreate(Bundle savedInstanceState) { // Houses h = new Houses(); //Activity where my Houses get generated super.onCreate(savedInstanceState); setContentView(R.layout.activity_buy_houses); Log.d("1. Step", "!!!!!!!!!!!!!!!!!!!!!!"); // for(int id=0; id<=8;id++){ // classes.add(h.NewHouseProps[id][0]); // Log.d("Klasse: ", Integer.toString(h.NewHouseProps[id][0])); // } // Log.d("2. Step", "!!!!!!!!!!!!!!!!!!!!!!"); /* classes.add(R.drawable.apartment); //Class 0 classes.add(R.drawable.townhouse); //Class 1 classes.add(R.drawable.bungalow); //Class 2 classes.add(R.drawable.villa); //Class 3 */ mPager = findViewById(R.id.vpPager); mPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager(), classes); mPager.setAdapter(mPagerAdapter); } public static ArrayList<Integer> getClasses() { Houses h = new Houses(); classes = new ArrayList<>(); for(int id=0 ; id<=8; id++) { classes.add(h.NewHouseProps[id][0]); } return classes; } @Override public void onBackPressed() { //ViewPager Last Page or Back if (mPager.getCurrentItem() == 0) { super.onBackPressed(); } else { mPager.setCurrentItem(mPager.getCurrentItem() - 1); } }

这样的类

FragmentBuyHouse

Android初学者// //我应该将变量填满后，为什么变量全为0？

1 个答案: