12

我有一个应用程序，它有一个 Spinner，我想用一些数字（4、8、12、16）填充它。我在 strings.xml 中使用上述项目创建了一个整数数组对象，将 Spinner 的条目设置为整数数组，当我运行应用程序时，我得到：

04-19 23:38:48.016: ERROR/AndroidRuntime(10193): java.lang.NullPointerException
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:355)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.ArrayAdapter.getView(ArrayAdapter.java:323)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:198)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.View.measure(View.java:7965)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:2989)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:888)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:350)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:278)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.View.measure(View.java:7965)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:2989)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.View.measure(View.java:7965)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:464)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:278)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.View.measure(View.java:7965)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:2989)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.View.measure(View.java:7965)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.ViewRoot.performTraversals(ViewRoot.java:763)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1632)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.os.Looper.loop(Looper.java:123)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at android.app.ActivityThread.main(ActivityThread.java:4310)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at java.lang.reflect.Method.invokeNative(Native Method)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at java.lang.reflect.Method.invoke(Method.java:521)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-19 23:38:48.016: ERROR/AndroidRuntime(10193):     at dalvik.system.NativeStart.main(Native Method)

一旦我将数组更改为字符串数组，它就可以正常工作。这是正常的吗？我意识到我可以（并且将会）将字符串数组值转换为 int，但我必须这样做似乎很奇怪。

谢谢！

编辑：有人吗？任何事物？

4

2 回答 2

25

不支持您尝试执行的操作。

你可能有一些看起来像这样的代码：

ArrayAdapter adapter = ArrayAdapter.createFromResource(this,
    R.array.numbers, android.R.layout.simple_spinner_item);

这当然是调用以下内容：

/**
 * Creates a new ArrayAdapter from external resources. The content of the array
 * is obtained through {@link android.content.res.Resources#getTextArray(int)}.
 *
 * @param context The application's environment.
 * @param textArrayResId The identifier of the array to use as the data source.
 * @param textViewResId The identifier of the layout used to create views.
 *
 * @return An ArrayAdapter<CharSequence>.
 */
public static ArrayAdapter<CharSequence> createFromResource(Context context,
        int textArrayResId, int textViewResId) {
    CharSequence[] strings = context.getResources().getTextArray(textArrayResId);
    return new ArrayAdapter<CharSequence>(context, textViewResId, strings);
}

调用getTextArray返回一个包含空对象的数组，而不是整数数组中值的字符串表示形式。深入挖掘揭示了问题的根源在于一种方法AssetManager：

/**
 * Retrieve the text array associated with a particular resource
 * identifier.
 * @param id Resource id of the string array
 */
/*package*/ final CharSequence[] getResourceTextArray(final int id) {
    int[] rawInfoArray = getArrayStringInfo(id);
    int rawInfoArrayLen = rawInfoArray.length;
    final int infoArrayLen = rawInfoArrayLen / 2;
    int block;
    int index;
    CharSequence[] retArray = new CharSequence[infoArrayLen];
    for (int i = 0, j = 0; i < rawInfoArrayLen; i = i + 2, j++) {
        block = rawInfoArray[i];
        index = rawInfoArray[i + 1];
        retArray[j] = index >= 0 ? mStringBlocks[block].get(index) : null;
    }
    return retArray;
}

此代码假定您提供了字符串数组的资源 id，因此无法从整数数组中正确提取值。

于 2010-05-21T05:00:59.633 回答
2

要克服这个问题，只需在您的 int 值周围加上引号

<array name="spinner_value">
    <item>"18"</item>
    <item>"8"</item>
</array>
于 2012-04-13T14:22:21.613 回答