具有多个行视图的自定义SimpleCursorAdapter

时间：2011-08-17 07:46:36

标签： android

我是java和android编程的新手。所以我的项目是一次巨大的学习经历。我正在使用一个cursorloader从数据库中检索数据，然后将该数据分配给自定义适配器。我想要做的是获取数据并根据数据是什么，将其分配给某个行布局。

将有大约6-12种不同的布局。数据包含不同类型的设备，例如灯，调光器，恒温器等。每种类型的设备都与类别编号相关联。灯的类别为3，调光器的类别编号为2.我想检查该类别，并根据编号将其分配给某个行布局。怎么会这样做呢？我正在尝试创建一个自定义simplecursoradapter。这是我到目前为止所发生的事情，但它崩溃了。

public class DeviceAdapter extends SimpleCursorAdapter {
    private LayoutInflater mInflater;
    private ViewHolder holder;
    private LightViewHolder lightholder;
    private TempViewHolder tempholder;

    public DeviceAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
        super(context, layout, c, from, to);
        this.mInflater = LayoutInflater.from(context);
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {

        if (cursor.getString(4).equals("17")) {;
            tempholder = (TempViewHolder)view.getTag();
            tempholder.name.setText(cursor.getString(1));
            tempholder.temp.setText(cursor.getString(10));
            tempholder.tempImage.setImageResource(R.drawable.thermometer);
        } else if (cursor.getString(4).equals("3")) {
            lightholder = (LightViewHolder)view.getTag();
            lightholder.name.setText(cursor.getString(1));
            lightholder.status.setText(cursor.getString(10));
            lightholder.lightImage.setImageResource(R.drawable.light_on);
        } else {
            holder = (ViewHolder)view.getTag();
            holder.name.setText(cursor.getString(1));
            holder.status.setText(cursor.getString(2));
        }
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        if (cursor.getString(4).equals("17")) {
            View view = mInflater.inflate(R.layout.temperature_device_list_item, null); 
            tempholder = new TempViewHolder();
            tempholder.name = (TextView)view.findViewById(R.id.devicename);
            tempholder.temp = (TextView)view.findViewById(R.id.temp);
            tempholder.tempImage = (ImageView)view.findViewById(R.id.tempImage);
            view.setTag(tempholder);
            return view;
        } else if (cursor.getString(4).equals("3")) {
            View view = mInflater.inflate(R.layout.light_list_item, null); 
            lightholder = new LightViewHolder();
            lightholder.name = (TextView)view.findViewById(R.id.devicename);
            lightholder.status = (TextView)view.findViewById(R.id.status);
            lightholder.lightImage = (ImageView)view.findViewById(R.id.deviceImage);
            view.setTag(lightholder);
            return view;
        } else {
            View view = mInflater.inflate(R.layout.device_list_item, null); 
            holder = new ViewHolder();
            holder.name = (TextView)view.findViewById(R.id.devicename);
            holder.status = (TextView)view.findViewById(R.id.status);
            view.setTag(holder);
            return view;
        }
    }


    private static class LightViewHolder {
        TextView name;
        TextView status;
        ImageView lightImage;
    }

    private static class TempViewHolder {
        TextView name;
        TextView temp;
        ImageView tempImage;
    }

    private static class ViewHolder {
        TextView name;
        TextView status;
    }

}

这看起来不错吗？记住，我是所有这一切的新手，并且很难找到一些好的例子。大多数代码示例都在调用getView，我读到你应该使用bindView和newView。

我的应用程序有一个房间片段和一个包含设备列表的片段。单击一个房间时会发生崩溃，列表将显示设备。如果我去点击另一个房间，应用程序将崩溃，我得到以下内容：

08-17 03:41:07.033: ERROR/AndroidRuntime(7210): FATAL EXCEPTION: main
08-17 03:41:07.033: ERROR/AndroidRuntime(7210): java.lang.ClassCastException: com.garrettpower.powerha.listadapters.listview.DeviceAdapter$LightViewHolder cannot be cast to com.garrettpower.powerha.listadapters.listview.DeviceAdapter$ViewHolder
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at com.garrettpower.powerha.listadapters.listview.DeviceAdapter.bindView(DeviceAdapter.java:42)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.CursorAdapter.getView(CursorAdapter.java:251)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.AbsListView.obtainView(AbsListView.java:1949)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.ListView.makeAndAddView(ListView.java:1756)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.ListView.fillSpecific(ListView.java:1302)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.ListView.layoutChildren(ListView.java:1587)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.AbsListView.onLayout(AbsListView.java:1800)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1542)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1403)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.LinearLayout.onLayout(LinearLayout.java:1314)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.View.layout(View.java:9588)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewGroup.layout(ViewGroup.java:3877)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewRoot.performTraversals(ViewRoot.java:1288)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.view.ViewRoot.handleMessage(ViewRoot.java:2046)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.os.Looper.loop(Looper.java:132)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at android.app.ActivityThread.main(ActivityThread.java:4123)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at java.lang.reflect.Method.invokeNative(Native Method)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at java.lang.reflect.Method.invoke(Method.java:491)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
08-17 03:41:07.033: ERROR/AndroidRuntime(7210):     at dalvik.system.NativeStart.main(Native Method)

1 个答案:

答案 0 :(得分：0)

我知道这已经很老了，但万一有人从谷歌或其他地方遇到过这种情况。

问题是bindView试图将TempViewHolder强制转换为ViewHolder - 这两个都是在适配器中定义的自定义内部类，并且因为它们是不同的，所以它们不能是从一个人转到另一个人。

永远假设非常重要ListView在convertView中为您提供与您需要的视图类型相同的视图类型。

至少这是堆栈跟踪显示的内容。可能还有其他问题，但修复将揭示下一个问题。

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