Question

如果这是一个简单的错误，我还没有在列表中使用过，所以请原谅我。我试图在用户想要查看他/她当前位置时动态更新列表。当用户点击按钮时，将获取当前位置（lat和lon）并将其插入列表中。我的清单没有得到更新。它甚至没有显示ArrayList之内的数据。

这是我在onCreate()

中声明我的列表的方式

listView        = (ListView)findViewById(R.id.list);
adapter = new CustomList(StartCalc.this, 0, 0);        
listView.setAdapter(adapter);

将lat和lon添加到arraylist

CustomList.lat.add(_CURLAT);
CustomList.lon.add(_CURLON);
adapter.notifyDataSetChanged();

我的CustomList类

public class CustomList extends ArrayAdapter<String>{


int _COUNT;
public static ArrayList<Double> lat = new ArrayList<Double>();
public static ArrayList<Double> lon = new ArrayList<Double>();
public static ArrayList<Double> ele = new ArrayList<Double>();
public static ArrayList<Double> dis = new ArrayList<Double>();

private final Activity context;

TextView location_list_textViewNO;
TextView location_list_lat;
TextView location_list_lon;
TextView location_list_ele;
TextView location_list_dis;


public CustomList(Activity context, int resource, int textViewResourceId) {
    super(context, R.layout.location_list, textViewResourceId);
    // TODO Auto-generated constructor stub
    this.context = context;
    this._COUNT  = textViewResourceId;

    lat.add(2.333);
    lon.add(5.03333);
    ele.add(5.77777777);
    dis.add(7.2222);    

}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    LayoutInflater inflater = context.getLayoutInflater();
    View rowView= inflater.inflate(R.layout.location_list, null, true);

    location_list_textViewNO = (TextView) rowView.findViewById(R.id.location_list_textViewNO);
    location_list_lat = (TextView) rowView.findViewById(R.id.location_list_lat);
    location_list_lon = (TextView) rowView.findViewById(R.id.location_list_lon);
    location_list_ele = (TextView) rowView.findViewById(R.id.location_list_ele);
    location_list_dis = (TextView) rowView.findViewById(R.id.location_list_dis);

    location_list_textViewNO.setText("A");
    location_list_lat.setText("LAT: " + lat.get(position));
    location_list_lon.setText("LON: " + lon.get(position));
    location_list_ele.setText("ELE: " + ele.get(position));
    location_list_dis.setText("DIS: " + dis.get(position)); 

    return rowView;
}

}

提前致谢

Answer 1

尝试拨打

listview.notifyDataSetChanged();

添加lat / long后

还要更改您的适配器，如下所示：

public class CustomList extends ArrayAdapter<Double>{//Set Double as data type


int _COUNT;
public static ArrayList<Double> lat = new ArrayList<Double>();
public static ArrayList<Double> lon = new ArrayList<Double>();
public static ArrayList<Double> ele = new ArrayList<Double>();
public static ArrayList<Double> dis = new ArrayList<Double>();

private final Activity context;

TextView location_list_textViewNO;
TextView location_list_lat;
TextView location_list_lon;
TextView location_list_ele;
TextView location_list_dis;


public CustomList(Activity context, int resource, int textViewResourceId) {
    super(context, R.layout.location_list, textViewResourceId,lat);//<---- Set one of the list as the 4th argument of super constructor 
    // TODO Auto-generated constructor stub
    this.context = context;
    this._COUNT  = textViewResourceId;

    lat.add(2.333);
    lon.add(5.03333);
    ele.add(5.77777777);
    dis.add(7.2222);    

}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    LayoutInflater inflater = context.getLayoutInflater();
    View rowView= inflater.inflate(R.layout.location_list, null, true);

    location_list_textViewNO = (TextView) rowView.findViewById(R.id.location_list_textViewNO);
    location_list_lat = (TextView) rowView.findViewById(R.id.location_list_lat);
    location_list_lon = (TextView) rowView.findViewById(R.id.location_list_lon);
    location_list_ele = (TextView) rowView.findViewById(R.id.location_list_ele);
    location_list_dis = (TextView) rowView.findViewById(R.id.location_list_dis);

    location_list_textViewNO.setText("A");
    location_list_lat.setText("LAT: " + lat.get(position));
    location_list_lon.setText("LON: " + lon.get(position));
    location_list_ele.setText("ELE: " + ele.get(position));
    location_list_dis.setText("DIS: " + dis.get(position)); 

    return rowView;
}

}

Answer 2

更新yout listview内容，您需要通知更改为适配器的数据集。尝试拨打

adapter.notifyDataSetChanged();

后

CustomList.lat.add（_CURLAT）; CustomList.lon.add（_CURLON）;

希望这有帮助。

尝试在适配器构造函数中传递'lat'和'lon'的默认值。像这样，

public CustomList(Activity context, int resource, int textViewResourceId,Double lat_val = 2.333, Double lon_val = 5.03333) {
super(context, R.layout.location_list, textViewResourceId,lat);//<---- Set one of the list as the 4th argument of super constructor 
// TODO Auto-generated constructor stub
this.context = context;
this._COUNT  = textViewResourceId;

lat.add(lat_val);
lon.add(lon_val);
ele.add(5.77777777);
dis.add(7.2222);

}

Answer 3

试试这个..

剪切以下行

public static ArrayList<Double> lat = new ArrayList<Double>();
public static ArrayList<Double> lon = new ArrayList<Double>();
public static ArrayList<Double> ele = new ArrayList<Double>();
public static ArrayList<Double> dis = new ArrayList<Double>();

并粘贴到 MainActivity

因为每次刷新适合启动再次的适配器

以及您在CustomList内添加错误的项目也会在MainActivity中添加这些项目。

列表没有得到更新

3 个答案: