android 如何在自定义适配器的特定位置添加文本

Question

我正在创建 android 应用程序来填充 GPS co-ordinates 列表，用户使用这样的自定义适配器输入

SELECTION         LAT        LONG         DISTANCE
-------------------------------------------------
  checkbox1    123.4546     456.48751      Text
  checkbox2    123.4546     456.48751      Text
  checkbox3    123.4546     456.48751      Text
  checkbox4    123.4546     456.48751      Text

如果用户选择 check-box 1 那么我必须找到从 check-box 1 lat long 到 check-box 2,check-box 3,check-box-4 经纬度。这里我需要在 Text 各自位置的字段中显示结果文本，但在这里我只在最后一个位置得到结果，谁能告诉我如何实现它，仅供参考：[! [在此处输入图片描述][2]][2] 本sc将为您详细解释。如果我检查一个值，它只更新最后一个值的结果，但我需要更新并显示整个数据的结果这是我的代码

check_locations.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {

                latitude_string = location.getLatitude();
                longitude_string = location.getLongitude();
                baseLat_double = Double.parseDouble(latitude_string);
                baseLong_double = Double.parseDouble(longitude_string);
                location_a = new Location("Base position");
                location_a.setLatitude(Double.parseDouble(latitude_string));
                location_a.setLongitude(Double.parseDouble(longitude_string));
                location_b = new Location("End position");
                for (int i = 0; i < objects.size(); i++) {
                    finalLat_double = Double.parseDouble(objects.get(i).getLatitude());
                    finalLong_double = Double.parseDouble(objects.get(i).getLongitude());
                    location_b.setLatitude(finalLat_double);
                    location_b.setLongitude(finalLong_double);
                    distance = location_a.distanceTo(location_b);
                    distance = distance * 1.609344;
                    objects.get(i).setDistance(String.valueOf(distance));
                    }
                notifyDataSetChanged();
                distance_text.setText(location.getDistance());

            }
        }
    });


    return locations_row;
}

Answer 1

检查您的 xml 布局，确保您的行 ID 是唯一的并且您正在正确使用 distance_text Textview 对象。也许需要在 for 循环中刷新对象？

对我来说，你的这段代码有点难读，但是你在哪里使用你的 ViewGroup parent 和 View convertView？来自

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

对于我的快速概览，您只获得 (TextView) locations_row.findViewById(R.id.txt_distance); 的 1 个实例，这是您视图中的最后一个位置。确保它根据需要刷新。

Answer 2

像这样修改你的getView()方法

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

    final View locations_row = LayoutInflater.from(context).inflate(R.layout.layout_adapter_list_details, null);
    final Locations_modle location = (Locations_modle) objects.get(position);
    TextView text_cust_name = (TextView) locations_row.findViewById(R.id.txt_cust_name_heading);
    TextView latitude = (TextView) locations_row.findViewById(R.id.txt_latitude);
    latitude.setText(location.getLatitude());
    TextView longitude = (TextView) locations_row.findViewById(R.id.txt_longitude);
    TextView distance_text = (TextView) locations_row.findViewById(R.id.txt_distance);
    if (StringUtils.isEmpty(location.getDistance()))
        distance_text.setText("DISTANCE");
    longitude.setText(location.getLongitude());
    text_cust_name.setText(location.getLocationName());
    CheckBox check_locations = (CheckBox) locations_row.findViewById(R.id.check_locations);
    check_locations.setTag(position);

    if (position == selectedPostion) {
        check_locations.setChecked(true);
    } else {
        check_locations.setChecked(false);
    }
    check_locations.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {

                selectedPostion = (int) buttonView.getTag();

                latitude_string = objects.get(selectedPostion).getLatitude();
                longitude_string = objects.get(selectedPostion).getLongitude();

                baseLat_double = Double.parseDouble(latitude_string);
                baseLong_double = Double.parseDouble(longitude_string);

                location_a = new Location("Base position");
                location_a.setLatitude(Double.parseDouble(latitude_string));
                location_a.setLongitude(Double.parseDouble(longitude_string));

                location_b = new Location("End position");


                for (int i = 0; i < objects.size(); i++) {
                    finalLat_double = Double.parseDouble(objects.get(i).getLatitude());
                    finalLong_double = Double.parseDouble(objects.get(i).getLongitude());
                    location_b.setLatitude(finalLat_double);
                    location_b.setLongitude(finalLong_double);
                    distance = location_a.distanceTo(location_b);
                    distance = distance * 1.609344;
                    objects.get(i).setDistance(distance);
                }
                Locations_Adapter.this.notifyDataSetChanged();
            }
        }
    });

    return locations_row;
}

Answer 3

您夸大了 locations_row 的普遍看法。这将每次创建一个新项目。您需要重用现有项目。我的意思是：

    if (convertView == null) {
        convertView = LayoutInflater.from(context).inflate(R.layout.layout_adapter_list_details, parent, false);
        holder = new ViewHolder(convertView);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

您甚至没有使用任何 View convertView 或 final ViewGroup parent 因此，从搜索列表视图适配器的 ViewHolder 模式开始。

android 如何在自定义适配器的特定位置添加文本

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