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社区首页 >问答首页 >Json BaseAdapter

问Json BaseAdapter
EN

Stack Overflow用户
提问于 2014-01-15 00:16:29
回答 3查看 324关注 0票数 0

我尝试从url中解析json并显示项目listview(图片和文本)。我有一个有问题的适配器在listview上添加相同的项。在我的URl上，我有20个项目，一开始似乎很好，但是当我尝试滚动列表时，记录是相同的(更具体地说，记录最初是列表)可能我的问题是BaseAdapter，这是我的代码

代码语言：javascript
复制
private LayoutInflater inflater;
private Activity activity;
public ArrayList<HashMap<String, String>> data;
public ViewHolder holder;

public ImageLoader imageLoader;
HashMap<String, String> itemList;
private int screenSize;
MainActivity main;

public BRIgeAdapter(Activity a, ArrayList<HashMap<String, String>> d,
        int screenSize) {
    this.activity = a;
    this.data = d;
    this.screenSize = screenSize;
    inflater = (LayoutInflater) activity
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    imageLoader = new ImageLoader(activity.getApplicationContext());
}

public int getCount() {
    return data.size();
}

public Object getItem(int position) {
    return data.get(position);
}

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

@Override
public int getViewTypeCount() {
    return data.size();
}

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

    if (convertView == null) {
        holder = new ViewHolder();
        main = new MainActivity();
        convertView = inflater.inflate(R.layout.list_row, parent, false);

        holder.journal = (TextView) convertView
                .findViewById(R.id.smalljournal);
        holder.statId = (TextView) convertView
                .findViewById(R.id.smallstatID);

        holder.smallDescription1 = (TextView) convertView
                .findViewById(R.id.smallDescription1);
        holder.DateTime = (TextView) convertView
                .findViewById(R.id.smallDateTime);
        holder.thumb_image = (ImageView) convertView
                .findViewById(R.id.smallthumb);
        holder.title = (TextView) convertView.findViewById(R.id.smalltitle);
        holder.description = (TextView) convertView
                .findViewById(R.id.smallDescription);

        convertView.setTag(holder);
        itemList = data.get(position);


        holder.journal.setText(itemList.get(MainActivity.KEY_journal));
        // holder.DateTime.setText(itemList.get(MainActivity.KEY_pubDate));
        holder.statId.setText(itemList.get(MainActivity.KEY_statID));
        holder.smallDescription1.setText(itemList
                .get(MainActivity.KEY_description));
        holder.journal.setTypeface(MainActivity.tf2);

        String titleString = itemList.get(MainActivity.KEY_title);

        Calendar cal = new GregorianCalendar(2013, 11, 20);
        DateFormat df = new SimpleDateFormat("dd.MM.yyyy");

        // DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

        String date = df.format(cal.getTime());

        String DateTime = itemList.get(MainActivity.KEY_pubDate);
        DateTime = date;

        holder.DateTime.setText(DateTime);

        holder.thumb_image.setScaleType(ScaleType.FIT_XY);

        holder.title.setText(titleString);
        holder.title.setTypeface(MainActivity.tf2);

        holder.title.setLineSpacing(2, 1.2f);
        holder.description.setLineSpacing(2, 1.2f);

        if (screenSize == Configuration.SCREENLAYOUT_SIZE_NORMAL)
            holder.description.setVisibility(View.INVISIBLE);
        else
            holder.description.setText(itemList
                    .get(MainActivity.KEY_description));

        holder.description.setTypeface(MainActivity.tf2);
        imageLoader.DisplayImage(itemList.get(MainActivity.KEY_image),
                holder.thumb_image);

    }
    return convertView;
}

static class ViewHolder {
    public TextView journal, title, description, smallDescription1,
            DateTime, statId;
    ImageView thumb_image;
}

如果有人知道如何解决我的问题，请帮助我，谢谢

android
json
baseadapter
EN

回答 3

Stack Overflow用户

发布于 2014-01-15 00:30:35

创建holder时出现问题..

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

代码语言：javascript
复制
if (convertView == null) {
    holder = new ViewHolder();
    main = new MainActivity();
    convertView = inflater.inflate(R.layout.list_row, parent, false);

    holder.journal = (TextView) convertView
            .findViewById(R.id.smalljournal);
    holder.statId = (TextView) convertView
            .findViewById(R.id.smallstatID);

    holder.smallDescription1 = (TextView) convertView
            .findViewById(R.id.smallDescription1);
    holder.DateTime = (TextView) convertView
            .findViewById(R.id.smallDateTime);
    holder.thumb_image = (ImageView) convertView
            .findViewById(R.id.smallthumb);
    holder.title = (TextView) convertView.findViewById(R.id.smalltitle);
    holder.description = (TextView) convertView
            .findViewById(R.id.smallDescription);

    convertView.setTag(holder);

}else{ holder=convertview.getTag()；} itemList =data.get(位置)；

代码语言：javascript
复制
    holder.journal.setText(itemList.get(MainActivity.KEY_journal));
    // holder.DateTime.setText(itemList.get(MainActivity.KEY_pubDate));
    holder.statId.setText(itemList.get(MainActivity.KEY_statID));
    holder.smallDescription1.setText(itemList
            .get(MainActivity.KEY_description));
    holder.journal.setTypeface(MainActivity.tf2);

    String titleString = itemList.get(MainActivity.KEY_title);

    Calendar cal = new GregorianCalendar(2013, 11, 20);
    DateFormat df = new SimpleDateFormat("dd.MM.yyyy");

    // DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

    String date = df.format(cal.getTime());

    String DateTime = itemList.get(MainActivity.KEY_pubDate);
    DateTime = date;

    holder.DateTime.setText(DateTime);

    holder.thumb_image.setScaleType(ScaleType.FIT_XY);

    holder.title.setText(titleString);
    holder.title.setTypeface(MainActivity.tf2);

    holder.title.setLineSpacing(2, 1.2f);
    holder.description.setLineSpacing(2, 1.2f);

    if (screenSize == Configuration.SCREENLAYOUT_SIZE_NORMAL)
        holder.description.setVisibility(View.INVISIBLE);
    else
        holder.description.setText(itemList
                .get(MainActivity.KEY_description));

    holder.description.setTypeface(MainActivity.tf2);
    imageLoader.DisplayImage(itemList.get(MainActivity.KEY_image),
            holder.thumb_image);

}
return convertView;

}

票数 0
EN

Stack Overflow用户

发布于 2014-01-15 00:32:46

我认为您的问题出在您的getView方法上。

代码语言：javascript
复制
@Override
public View getView(int position, View convertView, ViewGroup parent) {

if (convertView == null) {
    holder = new ViewHolder();
    main = new MainActivity();
    convertView = inflater.inflate(R.layout.list_row, parent, false);

    holder.journal = (TextView) convertView
            .findViewById(R.id.smalljournal);
    holder.statId = (TextView) convertView
            .findViewById(R.id.smallstatID);

    holder.smallDescription1 = (TextView) convertView
            .findViewById(R.id.smallDescription1);
    holder.DateTime = (TextView) convertView
            .findViewById(R.id.smallDateTime);
    holder.thumb_image = (ImageView) convertView
            .findViewById(R.id.smallthumb);
    holder.title = (TextView) convertView.findViewById(R.id.smalltitle);
    holder.description = (TextView) convertView
            .findViewById(R.id.smallDescription);

    convertView.setTag(holder);

 }

    ViewHolder holder = (ViewHolder ) convertView.getTag()

    itemList = data.get(position);


    holder.journal.setText(itemList.get(MainActivity.KEY_journal));
    // holder.DateTime.setText(itemList.get(MainActivity.KEY_pubDate));
    holder.statId.setText(itemList.get(MainActivity.KEY_statID));
    holder.smallDescription1.setText(itemList
            .get(MainActivity.KEY_description));
    holder.journal.setTypeface(MainActivity.tf2);

    String titleString = itemList.get(MainActivity.KEY_title);

    Calendar cal = new GregorianCalendar(2013, 11, 20);
    DateFormat df = new SimpleDateFormat("dd.MM.yyyy");

    // DateFormat df = new SimpleDateFormat("yyyy-MM-dd");

    String date = df.format(cal.getTime());

    String DateTime = itemList.get(MainActivity.KEY_pubDate);
    DateTime = date;

    holder.DateTime.setText(DateTime);

    holder.thumb_image.setScaleType(ScaleType.FIT_XY);

    holder.title.setText(titleString);
    holder.title.setTypeface(MainActivity.tf2);

    holder.title.setLineSpacing(2, 1.2f);
    holder.description.setLineSpacing(2, 1.2f);

    if (screenSize == Configuration.SCREENLAYOUT_SIZE_NORMAL)
        holder.description.setVisibility(View.INVISIBLE);
    else
        holder.description.setText(itemList
                .get(MainActivity.KEY_description));

    holder.description.setTypeface(MainActivity.tf2);
    imageLoader.DisplayImage(itemList.get(MainActivity.KEY_image),
            holder.thumb_image);

}
return convertView;
}

另外，如果MainActivity确实是安卓活动，请不要为列表中的每一项都实例化它

票数 0
EN

Stack Overflow用户

发布于 2014-01-15 02:04:07

您的问题出在您的getView()函数上，因为您说的是if (convertView==null)，并且您在那里做了所有的工作，但是如果convertview不为null，所有内容看起来都很相似，所以您应该添加else条件，我希望它能给您一些启发

票数 0
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/21118356

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