高效的适配器具有java.lang.ClassCastException吗? [英] Efficient adapter has java.lang.ClassCastException?

问题描述

观看此处之后，我尝试实现自己的高效适配器，

After watching here I try to implement my own efficient adapter,

我的ViewHolder类几乎相同:

My ViewHolder class almost same:

static class ViewHolder {
        ImageButton button;
        TextView txtView;
    }

getView方法如下:

getView method look like:

private void getView(...) {

    if(convertView == null) {
        convertView = LayoutInflater.from(
                parent.getContext()).inflate(R.layout.linear_container,
                        parent, false);

        holder = new ViewHolder();
        convertView.setTag(holder);
    } else {
        // erro line
        holder = (ViewHolder) convertView.getTag();
    }

    LinearLayout llCustomImgViewContainer = (LinearLayout) convertView
            .findViewById(R.id.llContainer);
    llCustomImgViewContainer.setTag(viewPosition);

    return converView;
}

但是这里一旦开始绘制新视图，就会给我错误

but here once new view started to draw, it give me error

D/AndroidRuntime(748):关闭VM W/dalvikvm(748):threadid = 1:线程以未捕获的异常退出(group = 0x412a4300) E/AndroidRuntime(748):致命异常:主要 E/AndroidRuntime(748): java.lang.ClassCastException:java.lang.Integer无法转换为com.droid.test.widget.customListView $ CustomBaseAdapter $ ViewHolder

D/AndroidRuntime( 748): Shutting down VM W/dalvikvm( 748): threadid=1: thread exiting with uncaught exception (group=0x412a4300) E/AndroidRuntime( 748): FATAL EXCEPTION: main E/AndroidRuntime( 748): java.lang.ClassCastException: java.lang.Integer cannot be cast to com.droid.test.widget.customListView$CustomBaseAdapter$ViewHolder

有人知道这是怎么回事吗?

any one have idea what is wrong here?

推荐答案

似乎一开始就是

convertView.setTag(holder);

您要设置与此视图关联的标签(是holder)，但稍后使用

line you are setting the tag(which is holder) associated with this view but later with

llCustomImgViewContainer.setTag(viewPosition);

您正在将viewPosition设置为标签.然后可能在

you are setting viewPosition as a tag. Then probably in

holder = (ViewHolder) convertView.getTag();

您的代码尝试将Integer转换为ViewHolder并引发java.lang.ClassCastException.

your code trying to cast Integer to ViewHolder and throws a java.lang.ClassCastException.

如果我没记错，这就是"linear_container"布局的结构

If I'm not wrong and this is the structure of the "linear_container" layout

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/llContainer">

    <!-- some views -->

</LinearLayout>

视图从

LayoutInflater.from(parent.getContext()).inflate(R.layout.linear_container,parent,false);

和从

convertView.findViewById(R.id.llContainer);

应该相同.

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