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我在下面的代码中使用 getView() 方法。我正在尝试遍历对象列表并获取它们的索引。在下面的代码中，我使用了一个 while 循环来执行此操作。但是，我没有得到预期的结果。我的列表包含 30 个对象，称为项目。我正在使用 while 循环并通过以下方法调用索引：items.get(j)和items.indexOf(j). 我没有得到与列表中的索引相对应的整数，而是得到 -1 的索引或内存地址。大小为 30 的列表如何获得 -1 索引？请在下面查看我的代码。

问题1：如何打印出列表中每个对象的索引。

问题2：这种奇怪的行为是否与getview回收listview有关的内存泄漏？

package com.convention.notification.app;

import java.util.Iterator;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class NewsRowAdapter extends ArrayAdapter<Item> {

    private Activity activity;
    private List<Item> items;
    private Item objBean;
    private int row;
    private List<Integer> disable;
    View view ;

    public NewsRowAdapter(Activity act, int resource, List<Item> arrayList, List<Integer> disableList) {
        super(act, resource, arrayList);
        this.activity = act;
        this.row = resource;
        this.items = arrayList;
        this.disable=disableList;

        System.out.println("results of delete list a:"+disable.toString()); 

    }

     public long getItemId(int position){
           return position;
        }

        public Item getItem(int position){
             return null;
           }



            @Override
            public View getView(final int position, View convertView, ViewGroup parent) {
                View view = convertView;
                ViewHolder holder;
                if (view == null) {
                    LayoutInflater inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                    view = inflater.inflate(row, null);

                    long id=getItemId(position);
                    //System.out.println(" at position "+position);


                     int j=0; 
                     System.out.println("item size at  "+items.size());
                        while (j< items.size())
                        {
                                System.out.println("while loop items.get(index): " +items.get(j) );
                                System.out.println( "while loop item.indexOf(index): "+items.indexOf(j) );
                                j++;
                        }

                    try{



                            //  System.out.println("item size at  "+items.size());

                                    for(int k =0;k< items.size();k++){

                                //      System.out.println("item index at "+items.get(k));
                                //      System.out.println("value of index "+k);

//                                      if(id == disable.get(k)){
//                                          view.setBackgroundColor(Color.YELLOW);
//                                          //System.out.println("background set to yellow at disable list "+disable.get(j));
//                                      //  System.out.println("background set to yellow at id "+id);
//                                          break;
//                                      } else {
//                                          view.setBackgroundColor(Color.WHITE);
//                                      //  System.out.println("background set to white at position "+position);
//                                      }
//                                  

                                    }


                                //}
                    }catch(IndexOutOfBoundsException e){

                    //System.out.println(" crash");
                    }




                    //ViewHolder is a custom class that gets TextViews by name: tvName, tvCity, tvBDate, tvGender, tvAge;
                    holder = new ViewHolder();

                    /* setTag Sets the tag associated with this view. A tag can be used to
                     *  mark a view in its hierarchy and does not have to be unique 
                     *  within the hierarchy. Tags can also be used to store data within
                     *   a view without resorting to another data structure.

        */
                    view.setTag(holder);
                } else {

                    //the Object stored in this view as a tag
                    holder = (ViewHolder) view.getTag();
                }

                if ((items == null) || ((position + 1) > items.size()))
                    return view;

                objBean = items.get(position);


        holder.tv_event_name = (TextView) view.findViewById(R.id.tv_event_name);
        holder.tv_event_date = (TextView) view.findViewById(R.id.tv_event_date);
        holder.tv_event_start = (TextView) view.findViewById(R.id.tv_event_start);
        holder.tv_event_end = (TextView) view.findViewById(R.id.tv_event_end);
        holder.tv_event_location = (TextView) view.findViewById(R.id.tv_event_location);


        if (holder.tv_event_name != null && null != objBean.getName()
                && objBean.getName().trim().length() > 0) {
            holder.tv_event_name.setText(Html.fromHtml(objBean.getName()));

        }
        if (holder.tv_event_date != null && null != objBean.getDate()
                && objBean.getDate().trim().length() > 0) {
            holder.tv_event_date.setText(Html.fromHtml(objBean.getDate()));
        }
        if (holder.tv_event_start != null && null != objBean.getStartTime()
                && objBean.getStartTime().trim().length() > 0) {
            holder.tv_event_start.setText(Html.fromHtml(objBean.getStartTime()));
        }
        if (holder.tv_event_end != null && null != objBean.getEndTime()
                && objBean.getEndTime().trim().length() > 0) {
            holder.tv_event_end.setText(Html.fromHtml(objBean.getEndTime()));
        }
        if (holder.tv_event_location != null && null != objBean.getLocation ()
                && objBean.getLocation ().trim().length() > 0) {
            holder.tv_event_location.setText(Html.fromHtml(objBean.getLocation ()));

        }


        return view;
    }

    public class ViewHolder {
        public TextView 
        tv_event_name,
        tv_event_date,
        tv_event_start,
        tv_event_end,
        tv_event_location
        /*tv_event_delete_flag*/;


    }


}

Logcat：请注意，此 logcat 输出在一次启动中重复大约 5 到 7 次。我在这里缩短了它。

06-11 19:58:17.471: I/AndroidRuntime(1347): NOTE: attach of thread 'Binder Thread #3' failed
06-11 19:58:18.541: I/ActivityManager(60): Displayed com.convention.notification.app/.DataView: +1s161ms
06-11 19:58:20.471: I/System.out(1355): item disalbed is at postion :1
06-11 19:58:20.471: I/System.out(1355): item disalbed is at postion :6
06-11 19:58:20.471: I/System.out(1355): item disalbed is at postion :14
06-11 19:58:20.471: I/System.out(1355): item disalbed is at postion :15
06-11 19:58:20.471: I/System.out(1355): item disalbed is at postion :18
06-11 19:58:20.471: I/System.out(1355): results of delete list :[1, 6, 14, 15, 18]
06-11 19:58:20.481: I/System.out(1355): results of delete list a:[1, 6, 14, 15, 18]
06-11 19:58:20.481: I/System.out(1355):  set adapaer to list view called;
06-11 19:58:20.581: I/System.out(1355): item size at  30
06-11 19:58:20.581: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574210
06-11 19:58:20.581: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.581: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574488
06-11 19:58:20.581: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.581: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@405744e0
06-11 19:58:20.631: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.631: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574538
06-11 19:58:20.631: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.631: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574590
06-11 19:58:20.631: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.631: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@405745e8
06-11 19:58:20.642: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.642: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574640
06-11 19:58:20.642: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.642: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574698
06-11 19:58:20.642: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.642: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@405746f0
06-11 19:58:20.642: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.642: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574748
06-11 19:58:20.671: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.671: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@405747c0
06-11 19:58:20.671: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.681: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574818
06-11 19:58:20.681: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.681: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574870
06-11 19:58:20.681: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.681: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574928
06-11 19:58:20.681: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.721: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574980
06-11 19:58:20.721: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.721: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@405749d8
06-11 19:58:20.721: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.731: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574a30
06-11 19:58:20.731: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.731: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574a88
06-11 19:58:20.731: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.731: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574ae0
06-11 19:58:20.761: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.761: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574bb8
06-11 19:58:20.761: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.761: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574c30
06-11 19:58:20.761: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.761: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574c88
06-11 19:58:20.761: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.771: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574ce0
06-11 19:58:20.781: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.781: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574d38
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.811: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574d90
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.811: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574de8
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.811: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574e40
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.811: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574e98
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.811: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40574fa8
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
06-11 19:58:20.811: I/System.out(1355): while loop items.get(index): com.convention.notification.app.Item@40575000
06-11 19:58:20.811: I/System.out(1355): while loop item.indexOf(index): -1
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2 回答 2

0

该indexOf函数接受一个对象，并且应该是与列表相同类型的对象。items.indexOf(items.get(index))正确的语法也是如此。有关详细信息，请参阅http://docs.oracle.com/javase/7/docs/api/java/util/List.html#indexOf%28java.lang.Object%29

于 2012-06-11T20:33:34.820 回答
0

函数 items.get() 在找不到您要求的字符串值时返回 -1。因此，当直接与函数 indexOf 结合使用时，这可能会很危险，因为 -1 是无效索引。我建议您使用不同的编码技术ListIterator。它很常见，因为它简单且安全。这是一个简短的示例，使用您的对象项目：

Iterator it = items.iterator();
while (it.hasNext()) {
   System.out.println(it.next());
}

看看它看起来多么简单和安全。迭代器在数据填充/更新后随时调用，而不是在更新过程中。您可以从 Internet 上找到许多示例。

于 2012-06-11T22:17:14.843 回答