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我是android开发的新手。我注册了 Udacity 课程，我到了必须使用服装 arrayAdapter 来显示数据（文本）的列表视图的地方，我掌握了大部分内容，但我在显示数据时遇到了问题，即：当我启动我的活动时，listView 显示最后一项在可能的数组列表上，我几乎尝试了所有东西，但它们对我没有任何作用

我的数据

/**
 * Displays text to the user.
 */
public class Numbers {


    //First we Set the Stat of our Class :

    // English Translation
    public static String englishTranslation;

    //Tamazight Translation
    public static String tamazightTranslation;

    /**
     * Create a new Numbers Object :
     *
     * @param englishTranslation   is for ENGLISH NUMBERS
     * @param tamazightTranslation is for TAMAZIGHT NUMBERS
     */

    //Constructor
    public Numbers(String englishTranslation, String tamazightTranslation) {


        this.englishTranslation = englishTranslation;
        this.tamazightTranslation = tamazightTranslation;

    }

    //Getter
    public static String getEnglishTranslation() {
        return englishTranslation;
    }


    public static String getTamazightTranslation() {
        return tamazightTranslation;
    }


}


我的数组列表：

public class ActivityNumbers extends AppCompatActivity {

    //Add English numbers to The ARRAYList
    ArrayList<Numbers> englishNumbers = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_numbers);



        englishNumbers.add(new Numbers("One", "Yan"));
        englishNumbers.add(new Numbers("Two", "Sin"));
        englishNumbers.add(new Numbers("Three", "Krad"));
        englishNumbers.add(new Numbers("Four", "Koz"));
        englishNumbers.add(new Numbers("Five", "Smos"));
        englishNumbers.add(new Numbers("Six", "Sdis"));
        englishNumbers.add(new Numbers("Seven", "Sa"));
        englishNumbers.add(new Numbers("Eight", "Tam"));
        englishNumbers.add(new Numbers("Nine", "Tza"));
        englishNumbers.add(new Numbers("Ten", "Mraw"));

        //EnglishNumbers.remove(0);
        //EnglishNumbers.size();
        // EnglishNumbers.get(1);
        //Create a NEW TV object




        /**Creating an ArrayAdapter (DATA HOLDER)
         @param Context / the ACTIVITY concerned
         @param Android.R.layout : an XML layout file contains TextView predefined by Android
         @param Items to display */


        NumbersAdapter itemsAdapter = new NumbersAdapter (this, englishNumbers);

        // Linking the ListView object to a Variable
        ListView numbersListView = (ListView) findViewById(R.id.list);
        //Calling setAdapter Method on numbersListView with "itemsAdapter
        numbersListView.setAdapter(itemsAdapter);


    }


}


我的适配器：

public class NumbersAdapter extends ArrayAdapter<Numbers> {

    public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) {
        super(context, 0, englishNumbers);
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        View listItemView = convertView;
        if (listItemView == null) {
            listItemView = LayoutInflater.from(getContext()).inflate(R.layout.listitem, parent, false);
        }

        Numbers numbers = getItem(position);


        System.out.println(position);

        TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
        TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);


        tamazight_item.setText(numbers.getEnglishTranslation());
        System.out.println(numbers.getEnglishTranslation());

        english_item.setText(numbers.getTamazightTranslation());

        System.out.println(numbers.getTamazightTranslation());


        return listItemView;

    }
}
4

4 回答 4

1

试试这个方法

Context context; 
ArrayList<Numbers> englishNumbers;

public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) 
{
  this.context=context;
  this.englishNumbers=englishNumbers;
}

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    convertView= LayoutInflater.from(context).inflate(R.layout.listitem,parent,false);

    TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
    TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);


    tamazight_item.setText(englishNumbers.get(position).getEnglishTranslation());
    english_item.setText(englishNumbers.get(position).getTamazightTranslation());

    return convertView;
}

并且不要忘记让 NumbersAdapter 扩展 BaseAdapter

于 2019-02-07T12:02:00.777 回答
0

您的tamazightTranslation和englishTranslation属性在Numbers类上是静态的，这意味着它们是类属性。从变量和吸气剂中删除static，你应该没问题。在此处查看类属性和实例属性之间的区别https://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html

于 2019-02-07T11:47:02.980 回答
0

我已经改变了你的模型类和适配器类请按照这个它会工作

 public class Numbers {
    //First we Set the Stat of our Class :

    // English Translation
    private String englishTranslation;

    //Tamazight Translation
    private  String tamazightTranslation;

    public String getEnglishTranslation() {
        return englishTranslation;
    }

    public void setEnglishTranslation(String englishTranslation) {
        this.englishTranslation = englishTranslation;
    }

    public String getTamazightTranslation() {
        return tamazightTranslation;
    }

    public void setTamazightTranslation(String tamazightTranslation) {
        this.tamazightTranslation = tamazightTranslation;
    }
}


适配器类

    public class NumbersAdapter extends ArrayAdapter<Numbers> {
     private Context mContext;
     private ArrayList<Numbers>list;
     public NumbersAdapter(Context context, ArrayList<Numbers> englishNumbers) {
      super(context, 0, englishNumbers);
      this.mContext=context;
      this.list = englishNumbers;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        View listItemView = convertView;
        if (listItemView == null) {
            listItemView = LayoutInflater.from(mContext).inflate(R.layout.listitem, parent, false);
        }

        Numbers numbers = list.get(position);


        System.out.println(position);

        TextView tamazight_item = (TextView) listItemView.findViewById(R.id.tamazight_item);
        TextView english_item = (TextView) listItemView.findViewById(R.id.english_item);


        tamazight_item.setText(numbers.getEnglishTranslation());
        System.out.println(numbers.getEnglishTranslation());

        english_item.setText(numbers.getTamazightTranslation());

        System.out.println(numbers.getTamazightTranslation());


        return listItemView;

    }
}
于 2019-02-07T12:06:22.497 回答
0

如果它在您的列表视图中显示最后一项，可能有几个原因。

  1. 您需要getCount()在 ArrayAdapter 中覆盖以获得列表的大小。它可能会解决问题。

  2. 确保列表视图未在 xml 布局中的滚动视图内声明。如果是，请使用nestedscrollview 或其他方式正确处理它。

如果它在列表视图的所有行中显示相同的数据，那么它可能是

  1. 在您的情况下，您需要删除static属性前面的关键字，static这意味着属性或方法属于 Number 类，而不是属于您的 Number 类对象的实例。基本上，应该是这个原因。
于 2019-02-07T22:21:44.753 回答