从onCreate调用addPreferencesFromResource时在PreferenceFragment中使用onCreateView的奇怪错误

Question

我正在尝试将ImageView添加到首选项片段,以显示颜色设置的预览.我正在通过onCreateView方法访问imageview的实例来设置测试颜色,它将显示.但是它只有在我没有在onCreate方法中调用addPreferencesFromResource时才有效 - 这是一个问题,因为必须添加首选项.此外,如果我将调用留给addPreferencesFromResource,但删除整个onCreateView方法,程序将运行(没有可更新的imageview的albiet).

两种情况下的错误都是"内容具有id属性的视图'android.R.id.list',而不是ListView类"

我试图从onCreate访问imageview,但到那时布局项目被夸大了,我似乎无法访问显示的实际实例.

LogCat出错:

04-11 00:42:43.619: E/AndroidRuntime(5362): FATAL EXCEPTION: main
04-11 00:42:43.619: E/AndroidRuntime(5362): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.signalwidget/com.example.android.signalwidget.SignalWidgetConfigure}: java.lang.RuntimeException: Content has view with id attribute 'android.R.id.list' that is not a ListView class

这里是带有内联片段的PreferenceActivity:

public class SigConfigure extends PreferenceActivity {

private static int prefs=R.xml.pref_widget_colors;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //getFragmentManager().beginTransaction().replace(android.R.id.content, new ColorsFragment()).commit();

}

@Override
public void onBuildHeaders(List<Header> target) {
    loadHeadersFromResource(R.xml.pref_headers, target);
}

public static class ColorsFragment extends PreferenceFragment {


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

        addPreferencesFromResource(SignalWidgetConfigure.prefs);


    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        super.onCreateView(inflater, container, savedInstanceState);

        //just testing to see if the imageview can be accessed.
        View v = inflater.inflate(R.layout.layout_pref_row, container, false);
        ImageView iv = (ImageView) v.findViewById(R.id.color_preview);
        iv.setBackgroundColor(Color.CYAN);

        return v;
    }


}}

这是pref_widget_colors中的首选项定义

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <Preference
        android:key="wifi_signal_color"
        android:title="WiFi Signal Color" >
        <intent
            android:action="android.intent.action.VIEW"
             android:targetClass="com.example.android.signalwidget.colorpicker.PickerActivity"
            android:targetPackage="com.example.android.signalwidget" />
    </Preference>
    <Preference
        android:key="cell_signal_color"
        android:title="Cell Signal Color" >
        <intent
            android:action="android.intent.action.VIEW"
            android:targetClass="com.example.android.signalwidget.colorpicker.PickerActivity"
            android:targetPackage="com.example.android.signalwidget" />
    </Preference>

</PreferenceScreen>

以下是layout_pref_row.xml中包含imageview的布局

<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:orientation="vertical" >

    <ImageView
        android:id="@+id/color_preview"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_marginTop="5dp"
        android:background="#aaa" />
</LinearLayout>

尽管有错误,我在项目的任何地方都没有使用ListView或ListFragment.这几乎看起来像一个机器人的bug.任何建议将不胜感激.

Answer 1

当您为PreferenceActivity或PreferenceFragment创建自定义layot时,您必须提供一个ID为android.R.id.list的ListView,其中Preferences将转到.

<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:orientation="vertical" >

    <ImageView
        android:id="@+id/color_preview"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_marginTop="5dp"
        android:background="#aaaaaa" />

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="5dp" />

</LinearLayout>