从onCreate调用addPreferencesFromResource时在PreferenceFragment中使用onCreateView产生奇怪的错误 [英] Strange Error using onCreateView in PreferenceFragment when calling addPreferencesFromResource from onCreate

问题描述

我正在尝试将ImageView添加到首选项片段中，以显示颜色设置的预览.我正在通过onCreateView方法访问imageview的实例以设置测试颜色，它将显示.但是，它仅在我未在onCreate方法中调用addPreferencesFromResource的情况下有效-这是一个问题，因为必须添加首选项.另外，如果我保留对addPreferencesFromResource的调用，但删除整个onCreateView方法，则程序将运行(没有可更新的imageview的情况).

I'm trying to add an ImageView to a preference fragment in order to show a preview of a color setting. I'm accessing the instance of the imageview via the onCreateView method toset the test color, and it will display. However it only works if I don't call addPreferencesFromResource in the onCreate method - which is a problem since the preferences must be added. Also if I leave the call to addPreferencesFromResource, but remove the entire onCreateView method the program will run (albiet without the updatable imageview).

两种情况下的错误均是内容具有ID属性为'android.R.id.list'的视图，而该属性不是ListView类"

The error in both cases is "Content has view with id attribute 'android.R.id.list' that is not a ListView class"

我试图从onCreate访问imageview，但是到那时布局项膨胀了，我似乎无法访问所显示的实际实例.

I have tried to access the imageview from onCreate, but by then the layout items are inflated and I can't seem to access the actual instance that is displayed.

LogCat错误:

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

以下是带有内联片段的PreferenceActivity:

Here the PreferenceActivity with inline Fragment:

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

Here is the preference definition in pref_widget_colors

<?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>

这是在layout_pref_row.xml中包含imageview的布局

Here is the layout containing the imageview in layout_pref_row.xml

<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，但我在项目的任何地方都没有使用ListView或ListFragment.这几乎就像是一个Android错误.任何建议将不胜感激.

Despite the error I am not using a ListView or a ListFragment anywhere in my project. This almost seems like an android bug. Any suggestion would be appreciated.

推荐答案

为PreferenceActivity或PreferenceFragment创建自定义布局时，您必须必须提供ID为 ListView 的 android.R.id.list (偏好设置所在的位置).

When you create a custom layot for a PreferenceActivity or a PreferenceFragment you must supply a ListView with id android.R.id.list where the Preferences go to.

<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>

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