适配器

Question

我有一个自定义适配器，当点击时，所有返回的位置都是正确的，除了第二个位置，它应该是1但是0（与第一个元素相同）。我试过使用v.getTag（）而不是直接使用位置，但它仍然给我相同的结果。适配器上的一小部分背景：我的ConnectedDeviceActivity将“All”，“No Connected Device”或设备名称发送到适配器。基于单击的项目，它调用AnalysisActivity，它显示与所单击项目相关的数据的图形。这是我的代码：

import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class AnalysisAdapter extends ArrayAdapter{

    private List appliance = new ArrayList<>();
    private List animation = new ArrayList<>();

    private String[] lookupName = {"heater", "dishwasher", "charger", "fridge"};

    private Context c;

    public AnalysisAdapter(Context context, int resource)
    {
        super(context, resource);
        this.c = context;
    }

    public void add(String newAppliance)
    {
        if(newAppliance.equals("All") || newAppliance.equals("No Connected Device"))
        {
            Log.d("Adapter", newAppliance + " added with position " + -1);

            appliance.add(newAppliance);
            animation.add(-1);

            super.add(newAppliance);
        }
        else
        {
            int position = 0;

            for (int i = 0; i < lookupName.length; i++)
            {
                if (lookupName[i].equals(newAppliance))
                {
                    position = i;
                    i = lookupName.length;
                }
            }

            Log.d("Adapter", newAppliance + " added with position " + position);

            appliance.add(newAppliance);
            animation.add(position);

            super.add(newAppliance);
        }
    }

    public boolean isAlreadyInList(String testAppliance) { return this.appliance.contains(testAppliance);}

    static class RowHolder
    {
        TextView APPLIANCE;
        ImageView ANIMATION;
    }

    @Override
    public int getCount()
    {
        return this.appliance.size();
    }

    @Override
    public Object getItem(int position)
    {
        return this.appliance.get(position);
    }

    public void remove(String removeAppliance)
    {
        int removePosition = appliance.indexOf(removeAppliance);
        appliance.remove(removeAppliance);
        animation.remove(removePosition);
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row;
        row = convertView;
        RowHolder holder;

        final int currentPosition = position;

        //Inflate row
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.analysis_item, parent, false);

            holder = new RowHolder();

            holder.APPLIANCE = (TextView) row.findViewById(R.id.analysis_item_text);
            holder.ANIMATION = (ImageView) row.findViewById(R.id.animation_item_image);

            holder.APPLIANCE.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    for(int i = 0; i < appliance.size(); i ++)
                        Log.d("Adapter", "All appliance in order: " + appliance.get(i));

                    Log.d("Adapter", appliance.get(currentPosition) + " send to analysis with position " + currentPosition );

                    Intent intent= new Intent(c, AnalysisActivity.class);
                    intent.putExtra("DEVICENAME", (String) appliance.get(currentPosition));
                    intent.putExtra("STARTINGACTIVITY", "ConnectedDeviceActivity");
                    c.startActivity(intent);

                }
            });

            row.setTag(holder);
        } else
            holder = (RowHolder) row.getTag();

        //Display name
        String EM = (String) getItem(position);

        holder.APPLIANCE.setText(EM);

        int deviceID = (int) animation.get(position);


        if (deviceID == 0) //heater
            holder.ANIMATION.setBackgroundColor(Color.GREEN);
        else if (deviceID == 1) //dishwasher
            holder.ANIMATION.setBackgroundColor(Color.YELLOW);
        else if (deviceID == 2) //charger
            holder.ANIMATION.setBackgroundColor(Color.RED);
        else if (deviceID == 3)//fridge
            holder.ANIMATION.setBackgroundColor(Color.BLUE);

        return row;
    }
}

单击列表中的第二个元素时，日志显示以下内容（位置应为1）。结果显示我的设备列表是正确的，但点击的项目标记为0.其余的位置是正确的。也可能有必要提一下，适配器的元素是由ConnectedDeviceActivity中的侦听器添加的，它从在线数据库中获取信息。

D/DailyAdapter: All appliance in order: All
D/DailyAdapter: All appliance in order: charger
D/DailyAdapter: All appliance in order: dishwasher
D/DailyAdapter: All appliance in order: fridge
D/DailyAdapter: All appliance in order: heater
D/DailyAdapter: All send to analysis with position 0

在我的第二次尝试中，我在持有者之后添加了第一行，并使用了index而不是currentPosition。日志保持不变

holder.APPLIANCE.setTag(position);

int index = (int) v.getTag();

Log.d("Adapter", appliance.get(index) + " send to analysis with position " + index);

这是单击第3个元素时的日志（位置2）：

D/Adapter: All appliance in order: All
D/Adapter: All appliance in order: charger
D/Adapter: All appliance in order: dishwasher
D/Adapter: All appliance in order: fridge
D/Adapter: All appliance in order: heater
D/Adapter: dishwasher send to analysis with position 2

Answer 1

如果您必须获取列表中单击行的单击位置，则很容易获得它。改变这一行

int index = (int) v.getTag();

带

int index = position;

您正在使用此方法获取视图的位置 -

getView(int position, View convertView, ViewGroup parent)

只需将此位置用作行的位置。

此外，您需要知道 getView 方法中的 convertView 是什么，如果您检查 if（convertView == null），它何时变为null 在适配器代码中。 See the details here

Answer 2

请注意，您正在此行中显示索引。

Log.d（＆＃34; Adapter＆＃34;，appliance.get（currentPosition）+＆＃34;发送到位置分析＆＃34; + index）;

您的索引仅在此处更新一次

int index =（int）v.getTag（）;

因为当 convertView == null true 时， v.setTag（）只设置一次（位置始终为0）这里）

现在，这是v.imp -

所有这些代码都保存在此

中

row.setTag（保持器）;

并像这样检索 -

holder =（RowHolder）row.getTag（）;

所以无论你点击哪一行，它总是会打印0。

你可以打印位置或 currentPosition 或更新每一行的索引。