java - 在 TypedArray#getTextArray() 期间抛出异常

Question

这是我第一次创建自定义 View ，我试图通过 XML 用条目填充它——以类似于 Spinner 的方式。我显然在这里做错了什么，但我在 Spinner 之后设计了我的方法，所以我看不出哪里出了问题。

为了解释这段代码的 Intent ，我正在创建一个自定义首选项列表。 MultiChooserOption 是一个允许用户从选项列表中选择多项的项目。 TextOption 简单地定义将在列表中显示的 View ，即 - 有一个标题和一些其他元素，对于 TextOption 的子类，其他元素将是文本而不是小部件(复选框等)。

下面是对我构建它的方式以及我的 logcat 输出有任何影响的所有内容的来源。

属性.xml

<resources>

    <attr name="caption" format="string" />
    <attr name="options" format="reference" />

    <declare-styleable name="TextOption">
        <attr name="caption" />
        <attr name="text" format="string" />
    </declare-styleable>
    <declare-styleable name="MultiChooserOption">
        <attr name="options" />
    </declare-styleable>

</resources>

MultiChooserOption.java

public class MultiChooserOption extends TextOption<CharSequence> {

    public static final String TAG = MultiChooserOption.class.getSimpleName();

    private List<CharSequence> options;
    private MultiChoiceListView<CharSequence> choiceView;

    public MultiChooserOption(Context context) {

        super( context );
    }

    public MultiChooserOption(Context context, AttributeSet attrs) {

        super( context, attrs );
        initOptions( attrs );
    }

    private void initOptions( AttributeSet attrs ) {

        TypedArray attributesArray = getContext().obtainStyledAttributes( attrs, R.styleable.TextOption, 0, 0 );

        try {
            // this line is where things go wrong
            CharSequence[] optionsArray = attributesArray.getTextArray( R.styleable.MultiChooserOption_options );
            setOptions( Arrays.asList( optionsArray ) );
        }
        catch (NotFoundException e) {
            Log.e( TAG, e.getMessage(), e );
        }
        finally {
            attributesArray.recycle();
        }
    }
}

文本选项.java

public abstract class TextOption<T> extends LinearLayout {

    public static final String TAG = TextOption.class.getSimpleName();

    private TextView captionTextView;
    private TextView valueTextView;

    private String caption;
    private String value;

    public TextOption(Context context) {

        super( context );
        init();
    }

    public TextOption(Context context, AttributeSet attrs) {

        super( context, attrs );

        TypedArray attributesArray = context.obtainStyledAttributes( attrs, R.styleable.TextOption, 0, 0 );
        try {
            setCaption( attributesArray.getString( R.styleable.TextOption_caption ) );
            setValue( attributesArray.getString( R.styleable.TextOption_text ) );
        }
        finally {
            attributesArray.recycle();
        }

        init();
    }
}

options_fragment.xml

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:custom="http://schemas.android.com/apk/res/com.mypackage"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <com.mypackage.view.MultiChooserOption
            android:id="@+id/multichooser"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            custom:caption="@string/multichooser_caption"
            custom:options="@array/multichooser_options" />

    </LinearLayout>

</ScrollView>

数组.xml

<resources>

    <string-array name="multichooser_options">
        <item>@string/option1</item>
        <item>@string/option2</item>
        <item>@string/option3</item>
        <item>@string/option4</item>
        <item>@string/option5</item>
        <item>@string/option6</item>
    </string-array>

</resources>

字符串.xml

<resources>
    <string name="multichooser_caption">MultiChooser</string>
    <string name="option1">option 1</string>
    <string name="option2">option 2</string>
    <string name="option3">option 3</string>
    <string name="option4">option 4</string>
    <string name="option5">option 5</string>
    <string name="option6">option 6</string>
</resources>

OptionsFragment.java

public class OptionsFragment extends RoboSherlockFragment {

    public static final String TAG = OptionsFragment.class.getSimpleName();

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

        View view = inflater.inflate( R.layout.options_fragment, container, false );
        return view;
    }
}

日志输出

09-18 20:52:36.940: E/AndroidRuntime(4237): FATAL EXCEPTION: main
09-18 20:52:36.940: E/AndroidRuntime(4237): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mypackage/com.mypackage.ui.OptionsActivity}: android.view.InflateException: Binary XML file line #44: Error inflating class com.mypackage.view.MultiChooserOption
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.os.Looper.loop(Looper.java:137)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.ActivityThread.main(ActivityThread.java:5041)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at java.lang.reflect.Method.invokeNative(Native Method)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at java.lang.reflect.Method.invoke(Method.java:511)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at dalvik.system.NativeStart.main(Native Method)
09-18 20:52:36.940: E/AndroidRuntime(4237): Caused by: android.view.InflateException: Binary XML file line #44: Error inflating class com.mypackage.view.MultiChooserOption
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.createView(LayoutInflater.java:613)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.rInflate(LayoutInflater.java:749)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at com.mypackage.ui.OptionsFragment.onCreateView(OptionsFragment.java:27)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.support.v4.app.Fragment.performCreateView(Fragment.java:1460)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:911)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:551)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at com.github.rtyley.android.sherlock.roboguice.activity.RoboSherlockFragmentActivity.onStart(RoboSherlockFragmentActivity.java:46)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1164)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.Activity.performStart(Activity.java:5114)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153)
09-18 20:52:36.940: E/AndroidRuntime(4237):     ... 11 more
09-18 20:52:36.940: E/AndroidRuntime(4237): Caused by: java.lang.reflect.InvocationTargetException
09-18 20:52:36.940: E/AndroidRuntime(4237):     at java.lang.reflect.Constructor.constructNative(Native Method)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.view.LayoutInflater.createView(LayoutInflater.java:587)
09-18 20:52:36.940: E/AndroidRuntime(4237):     ... 27 more
09-18 20:52:36.940: E/AndroidRuntime(4237): Caused by: java.lang.NullPointerException
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.content.res.AssetManager.getResourceTextArray(AssetManager.java:214)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.content.res.Resources.getTextArray(Resources.java:427)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at android.content.res.TypedArray.getTextArray(TypedArray.java:628)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at com.mypackage.view.MultiChooserOption.initOptions(MultiChooserOption.java:42)
09-18 20:52:36.940: E/AndroidRuntime(4237):     at com.mypackage.view.MultiChooserOption.<init>(MultiChooserOption.java:32)
09-18 20:52:36.940: E/AndroidRuntime(4237):     ... 30 more

因此，当 MultiChooserOption 中的行 CharSequence[] optionsArray = attributesArray.getTextArray( R.styleable.MultiChooserOption_options ); 执行时，将抛出异常，整个 shebang 崩溃。据我所知，我会尽可能多地关注 Spinner。

请帮助我了解我在这里做错了什么。

Answer 1

好吧，现在我觉得自己很傻。

扩展父 View 时，获取父 View 的样式属性不是一个好主意。

TypedArray attributesArray = getContext().obtainStyledAttributes( attrs, R.styleable.TextOption, 0, 0 );

应该是

TypedArray attributesArray = getContext().obtainStyledAttributes( attrs, R.styleable.MultiChooserOption, 0, 0 );