EfficientAdapter和项目的抢夺文字点击 [英] EfficientAdapter and grabbing text of item clicked

问题描述

有关EfficientAdapter什么code，我需要onListItemClick下要使用获得所选项目的文本？
我想：

For EfficientAdapter What code I need to use under onListItemClick to get text of selected item? I tried:

str=(String) ((TextView)l.getItemAtPosition(position)).getText()

但是，这不仅带来了CastException，因为它取了的LinearLayout视图持有的TextView和ImageView的（见code <一个href=\"http://developer.android.com/intl/de/resources/samples/ApiDemos/src/com/example/android/apis/view/List14.html\"相对=nofollow>这里）

请帮帮忙！

有些code的：

public class Bookmarks extends ListActivity {
public static Typeface mFace;
public EfficientAdapter eff;

private static class EfficientAdapter extends BaseAdapter {
    private LayoutInflater mInflater;

    public EfficientAdapter(Context context) {
        mInflater = LayoutInflater.from(context);
    }

    public int getCount() {
        return DAT.length;
    }

    public Object getItem(int position) {
        return position;
    }

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

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.list_item_text, null);
            holder = new ViewHolder();
            holder.text = (TextView) convertView.findViewById(R.id.text);
            holder.text.setTypeface(mFace);

            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.text.setText(DAT[position]);

        return convertView;
    }

    static class ViewHolder {
        TextView text;
    }
}

public Object getItem(int position) { 
    return position; 
}

public void onResume(Bundle icicle) {
    eff.notifyDataSetChanged();
}

protected void onListItemClick(ListView l, View v, int position, long id) {
    //////////CRASHES on next line!!!!!!!!!!!!!!!!!!
TextView tv = (TextView) l.getItemAtPosition(position);
    String str = tv.getText().toString();

}


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    eff = (new EfficientAdapter(this));
    setListAdapter(eff);
    registerForContextMenu(getListView());
}

}

推荐答案

有没有真正足够的信息，在你的问题（见上面我的意见），但在这里的答案是一个猜测：

There isn't really enough information in your question (see my comment above), but here's a guess at an answer:

首先，的getText（）是的记载返回的CharSequence，而不是字符串。它的会返回一个字符串，但你不知道它。因此，这将是更加安全的写：

First, getText() is documented to return a CharSequence, not a String. It might return a String, but you don't know that it does. So it would be safer to write:

str = ((TextView)l.getItemAtPosition(position)).getText().toString()

第二，如果还是不行，请尝试打破这种说法，让你可以在异常是来自一个更好的想法。像这样的东西，也许，可能是更清晰的：

Second, if that doesn't work, try breaking down that statement so you can get a better idea of where the exception is coming from. Something like this, perhaps, might be clearer:

TextView tv = (TextView) l.getItemAtPosition(position);
str = tv.getText().toString();

修改根据您的更新：

1）如果你打算实施 onListItemClick ，要确保你通过调用基类开头的方法，如下图所示。

1) If you're going to implement onListItemClick, be sure that you begin the method by calling up to the base class, as shown below.

2）这里的问题：（我意识到这在一个不同的例子，我认为不会是现在有必要）复制和粘贴后：<一href=\"http://developer.android.com/reference/android/widget/AdapterView.html#getItemAtPosition%28int%29\"相对=nofollow> ListView.getItemAtPosition 不返回查看所有;它从你的适配器（一个光标，一个数组项，等等。）来获取返回的TextView一个项目，你需要使用 findViewById ，或者更好的是，你的ViewHolder。我的认为的这将工作：

2) Here's the problem: (I realized this after copying and pasting in a different example, which I think won't be necessary now): ListView.getItemAtPosition doesn't return a View at all; it returns an item from your Adapter (a Cursor, an array entry, whatever.) To get the TextView, you need to use findViewById, or better still, your ViewHolder. I think this will work:

protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);

    ViewHolder holder = (ViewHolder) v.getTag();
    TextView tv = holder.text;
    String str = tv.getText().toString();
}

如果你仍然有问题，请复制并粘贴你得到异常的回溯。

If you're still having problems, please copy and paste the traceback for the exception that you're getting.

这篇关于EfficientAdapter和项目的抢夺文字点击的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！