我的 ArrayList 中的数据重复了数组最后输入的数据。这是什么原因？

Question

当我使用ArrayList自定义适配器在列表视图中列出图像时，代码没有显示任何错误。问题是，在使用代码时，只有我最后输入的数据在列表视图中显示。为什么不能查看之前输入的数据？我的活动课：public class SocialActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_social);        String json;        ImageView babu = (ImageView) findViewById(R.id.babu);        ListView lvsoc = (ListView) findViewById(R.id.list_social);        LinearLayout l1 = (LinearLayout) findViewById(R.id.layhead);        LayoutInflater inflater = null;        ArrayList<SubjectData> arrayList = new ArrayList<SubjectData>();        ArrayAdapter<SubjectData> a;        /*ArrayList<String> allcategory = new ArrayList<>();        ArrayList<String> allcategory1 = new ArrayList<>();        ArrayList<String> img = new ArrayList<>();        ArrayList<String> img1 = new ArrayList<>();*/        arrayList.add(new SubjectData("JAVA", "https://www.tutorialspoint.com/java/", "https://s18955.pcdn.co/wp-content/uploads/2017/11/Facebook-share-icon.png"));        arrayList.add(new SubjectData("Python", "https://www.tutorialspoint.com/python/", "https://www.tutorialspoint.com/python/images/python-mini.jpg"));        /*arrayList.add(new SubjectData("Javascript", "https://www.tutorialspoint.com/javascript/", "https://www.tutorialspoint.com/javascript/images/javascript-mini-logo.jpg"));        arrayList.add(new SubjectData("Cprogramming", "https://www.tutorialspoint.com/cprogramming/", "https://www.tutorialspoint.com/cprogramming/images/c-mini-logo.jpg"));        arrayList.add(new SubjectData("Cplusplus", "https://www.tutorialspoint.com/cplusplus/", "https://www.tutorialspoint.com/cplusplus/images/cpp-mini-logo.jpg"));

Answer 1

您SubjectData拥有所有静态字段。所以每个实例SubjectData都有相同的信息。

反而：

public class SubjectData {

    public String SubjectName;

    public String Link;

    public String Image;

    public SubjectData(String subjectName, String link, String image) {

        this.SubjectName = subjectName;

        this.Link = link;

        this.Image = image;

    }

}