Android: 如何为对象编写自定义数组适配器

Question

我正在尝试制作可用于对象“数据”的自定义数组适配器

 public class theAdapter extends ArrayAdapter {
private ArrayList <listToDo> list;
public theAdapter(Context context, ArrayList<listToDo>list) {
    super(context, R.layout.my_layout, list);
    this.list = list;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater =  LayoutInflater.from(getContext());
    View view =  inflater.inflate(R.layout.my_layout,parent,false);
    listToDo activity = (listToDo) getItem(position);
    TextView theTextView = (TextView) view.findViewById(R.id.textView);
    theTextView.setText(activity.things);
    CheckBox checkBox = (CheckBox) view.findViewById(R.id.checkbox);
    checkBox.setChecked(activity.checked);
    return view;
}

}

然而，这一次又一次地打印出同样的东西。例如，如果 ArrayList 有 1,2,3,4,5。（这不是我拥有的确切对象）它打印出 5、5、5、5、5。

编辑--------------------------------

        protected void dataRead (){
        File f = new File( Environment.getExternalStorageDirectory(),"user.txt");
        listToDo original = new listToDo ();
        try {
        FileInputStream fis = new FileInputStream(f);
        InputStreamReader temp = new InputStreamReader(fis);
        BufferedReader bis = new BufferedReader(temp);
        String activity;
        while ((activity = bis.readLine()) != null){
            String[] parts = activity.split("\t");
            original.things = parts[0];
            if (parts[1] == "1"){
                original.checked=true;
            }
            else{
                original.checked=false;
            }
            data.add(original);
            Log.v(TAG, original.things);
        }
            for (int i =0; i < data.size(); i++){
                Log.d(TAG,data.get(i).things);
            }
        bis.close();
    }
    catch  (Exception e) {
    }
     }

Answer 1

说明：您当前创建列表项的方式只会创建一个名为 "original" 的 listToDo 并在每次循环期间更改其中的值。同样在循环中，您再次添加相同的 original 对象，无论您在 user.txt 中有多少行。因此，让我们将 listToDo 实例创建移动到循环中，这样它将在每个循环中创建一个名为 original 的新 listTodo class 对象，设置一些值（选中和事物），然后添加到 data 列表

protected void dataRead (){
    File f = new File( Environment.getExternalStorageDirectory(),"user.txt");
    try {
        FileInputStream fis = new FileInputStream(f);
        InputStreamReader temp = new InputStreamReader(fis);
        BufferedReader bis = new BufferedReader(temp);
        String activity;
        while ((activity = bis.readLine()) != null){
            listToDo original = new listToDo ();
            String[] parts = activity.split("\t");
            original.things = parts[0];
            if ("1".equals(parts[1])) {
                original.checked=true;
            }
            else{
                original.checked=false;
            }
            data.add(original);
            Log.v(TAG, original.things);
        }
        for (int i =0; i < data.size(); i++){
            Log.d(TAG,data.get(i).things);
        }
        bis.close();
    }
    catch  (Exception e) {
    }
}

此外，我认为您的适配器 class 有点不对劲。

public class theAdapter extends ArrayAdapter<listToDo> {

    public theAdapter(Context context, ArrayList<listToDo> list) {
        super(context, R.layout.my_layout, list);
    }

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

        listToDo activity = (listToDo) getItem(position);

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

        TextView theTextView = (TextView) convertView.findViewById(R.id.textView);
        theTextView.setText(activity.things);
        CheckBox checkBox = (CheckBox) convertView.findViewById(R.id.checkbox);
        checkBox.setChecked(activity.checked);
        return convertView;
    }
}

这里有一个完整的教程以防万一： https://github.com/codepath/android_guides/wiki/Using-an-ArrayAdapter-with-ListView

Android: 如何为对象编写自定义数组适配器

Android: How to write customize array adapter for objects

android

object

android-arrayadapter

android-listview