找出点击的元素的android系统中的ListView父 [英] Finding out the parent of clicked element in android ListView

问题描述

我建设我根据材料第一应用从的http：// javatechig .COM /视频/ JSON-提要阅读器功能于Android的。
一切正常的话，到目前为止，但我发现一个错误的ListView与元素，这是我不能管理由我自己来解决:(
我已经2个字段扩展list_row_layout.xml：

I'm building my first app based on material from http://javatechig.com/video/json-feed-reader-in-android. Everything goes ok so far, but I found one bug with ListView elements, which I can not manage to resolve by myself :( I have extended list_row_layout.xml by 2 fields:

    <Button
    android:layout_width="wrap_content"
    android:layout_height="20dp"
    android:text="komcie"
    android:textSize="11sp"
    android:id="@+id/loadComments"
    android:layout_gravity="center|bottom"
    android:background="#bbb"
    android:layout_marginLeft="5dp"
    android:enabled="true"
    android:clickable="true"
    android:onClick="clickedLoadComments"
    android:elegantTextHeight="true"
    android:layout_toRightOf="@id/thumbImage"
    android:layout_below="@+id/content"
    android:padding="1px" />    

<ListView
    android:id="@+id/comment_list"
    android:layout_toRightOf="@id/thumbImage"
    android:layout_below="@+id/content"
    android:paddingTop="5dp"
    android:layout_marginTop="0dp"
    android:paddingLeft="5dp"
    android:layout_width="fill_parent"
    android:layout_height="0dp"
    android:cacheColorHint="#00000000"
    android:dividerHeight="1dp"
    android:focusable="false"
    android:listSelector="@drawable/list_selector_flatcolor"
    android:visibility="invisible" />

Button.android:onClick=clickedLoadComments功能加载的Json与元素融入的ListView / comment_list。它的工作原理相当精细。但是，如果有比屏幕上（〜8元）有一个bug可以显示更多的元素。 从点击的元素评论加载到在ListView每8个元素。
有些code：

Button.android:onClick="clickedLoadComments" function load Json with elements into ListView/comment_list. It works quite fine. But if there are more elements than could be displayed on screen (~8 elements) there is a bug. Comments from clicked element are loaded into every 8th element in a ListView. Some code:

    public void clickedLoadComments(View v)
{
    try {
        View parent = (View)v.getParent();
        ViewHolder t = (ViewHolder) parent.getTag();

        if( parent != null ) {
            this.loadCommentsForLeaf(parent);
        }
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }
}   

protected void loadCommentsForLeaf( View view )
{
    String tmpUrl = "http://some.url.com/Ajax/LoadComments?lid=" + this.currentLeafInUse;


    JSONObject commentsJson = this.getJSONFromUrl(tmpUrl);
    this.parseJsonComments(commentsJson);

    if( commentsJson != null )
        this.updateCommentList(view);
}   

public void updateCommentList( View view) {
    commentListView = (ListView) view.findViewById(R.id.comment_list);
    commentListView.setVisibility(View.VISIBLE);

CommentListAdapter cla = new CommentListAdapter(this, this.commentList.get(this.currentLeafInUse));
    commentListView.setAdapter(cla);



        // Set list height.
    ViewGroup.LayoutParams params = commentListView.getLayoutParams();
    params.height = setListViewHeightBasedOnItems(commentListView) + 20;
    commentListView.setLayoutParams(params);
    commentListView.requestLayout();

}   

CustomListAdapter.java code是大多相同，一个在教程。

CustomListAdapter.java code is mostly the same as the one in tutorial.

我真的AP preciate帮助，因为我花了很多时间想出来与不是成功：（

I would really appreciate help as I have spent many hours figuring it out with not success :(

推荐答案

这只是一个猜测。你可以发表您的适配器code和你的 parseJsonComments 此外，如果这是行不通的。

This is just a guess. You might post your Adapter code and your parseJsonComments also if this does not work.

的原因：

您所描述的，由于回收和意见的回用可能造成的问题。就拿从 http://android.amberfog.com

The problem you are describing might be caused due to the recycling and the reusage of Views. Take a look at this image from http://android.amberfog.com

正如你所看到的1项是重复使用，滚动后变成了8项。

As you can see the 1. items is reused and becomes the 8. item after scrolling.

让我们假设第1项具有 OnClickListener 这将更新项目的文本。
例如我们设置为点击文本后 OnClickListener 被触发。

Let's assume that Item 1 has an OnClickListener which updates a Text of the item. For example we set the text to "clicked" after the OnClickListener is triggered.

由于第1项被重新创造8项，第8项也将显示文本点击。

Because item 1 is reused to create item 8, item 8 will also display the text "clicked".

解决方案：

的常用方法是保存列表中的所有国家/内容（或其他），并更新getView调用一切。所以，如果你想更新文本：

The usual way is to save all states/content in a List(or whatever) and update everything in the getView call. So if you want to update text:

public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    ...
    holder.textView.setText(jsonTexts[position]);
    ...

    return convertView;
}

如果你想更新项目刚刚更新您的适配器持有的内容/一个JSONObjects列表（等），并调用 notifyDataSetChanged 。

public void updateCommentList(JSONObject commentsJson, int position) {
     // does not exist you might create something 
     //like that in your Adapter class
     commentListAdapter.updateItem(commentsJson,position); 
     commentListAdapter.notifyDataSetChanged();
}

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