将 BindingAdapter 与资源中的字符串数组结合使用

Question

我有一个几乎的简单想法：我想为具有数据绑定 API 和 BindingAdapter 的微调器生成一个适配器。这是我要使用的XML：

<Spinner
    android:id="@+id/country"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:value="@{address.country}"
    app:data="@{@array/countries}"
    app:keys="@{@array/iso_3166_2}"/>

这里的地址是一个简单的 class，它有一个名为 country 的字段，它是一个字符串，将包含一个 ISO-3166-2 字符串。为简单起见，值将是 "DE" 或 "US".

这是我的简化版 arrays.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="iso_3166_2">
        <item>DE</item>
        <item>US</item>
    </string-array>

    <string-array name="countries">
        <item>@string/country_DE</item>
        <item>@string/country_US</item>
    </string-array>
</resources>

对于绑定，我写了这个 BindingAdapter：

@BindingAdapter({"value", "data", "keys"})
public static void generateAdapter(Spinner spinner,
                                   String value,
                                   @ArrayRes int data,
                                   @ArrayRes int keys) {

}

当我尝试编译代码时出现此错误：

Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
java.lang.RuntimeException: Found data binding errors.
****/ data binding error ****msg:Identifiers must have user defined types from the XML file. countries is missing it
file:path/to/the/spinner-above.xml
loc:95:31 - 95:39
****\ data binding error ****

我的xml的第95行是这一行：app:value="@{address.country}"

你看到我哪里做错了吗？

顺便说一句，我不确定与数组资源相关的注释是否正确？我发现无法将其限制为字符串数组。

Answer 1

你可以通过参考stringArray而不是array来获取它。这是我使用 recyclerView 从资源中获取价值所做的工作，它运行良好，它也可能对您有所帮助。

在string.xml

<string-array name="myItems">
    <item>Item 1</item>
    <item>Item 2</item>
    <item>Item 3</item>
    <item>Item 4</item>
    <item>Item 5</item>
    <item>Item 6</item>
</string-array>

在layout.xml

app:entries="@{@stringArray/fi}"

您的情况可以是 app:data="@{@stringArray/countries}" 或 app:keys="@{@stringArray/iso_3166_2}"。

并在绑定方法中

@BindingAdapter({"entries"})
public static void entries(RecyclerView recyclerView, String[] array) {
    //get all values in array[] variable.
}

参考了解更多。

Answer 2

如果您想访问数据绑定布局文件中的其他资源类型，请参阅源代码

    public String toJava() {
        final String context = "getRoot().getContext()";
        final String viewName = requiresView() ? LayoutBinderWriterKt.getFieldName(mTarget) :
                "getRoot()";
        final String resources = viewName + ".getResources()";
        final String resourceName = mPackage + "R." + getResourceObject() + "." + mResourceId;
        if ("anim".equals(mResourceType)) return "android.view.animation.AnimationUtils.loadAnimation(" + context + ", " + resourceName + ")";
        if ("animator".equals(mResourceType)) return "android.animation.AnimatorInflater.loadAnimator(" + context + ", " + resourceName + ")";
        if ("bool".equals(mResourceType)) return resources + ".getBoolean(" + resourceName + ")";
        if ("color".equals(mResourceType)) return "android.databinding.DynamicUtil.getColorFromResource(" + viewName + ", " + resourceName + ")";
        if ("colorStateList".equals(mResourceType)) return "android.databinding.DynamicUtil.getColorStateListFromResource(" + viewName + ", " + resourceName + ")";
        if ("dimen".equals(mResourceType)) return resources + ".getDimension(" + resourceName + ")";
        if ("dimenOffset".equals(mResourceType)) return resources + ".getDimensionPixelOffset(" + resourceName + ")";
        if ("dimenSize".equals(mResourceType)) return resources + ".getDimensionPixelSize(" + resourceName + ")";
        if ("drawable".equals(mResourceType)) return "android.databinding.DynamicUtil.getDrawableFromResource(" + viewName + ", " + resourceName + ")";
        if ("fraction".equals(mResourceType)) {
            String base = getChildCode(0, "1");
            String pbase = getChildCode(1, "1");
            return resources + ".getFraction(" + resourceName + ", " + base + ", " + pbase +
                    ")";
        }
        if ("id".equals(mResourceType)) return resourceName;
        if ("intArray".equals(mResourceType)) return resources + ".getIntArray(" + resourceName + ")";
        if ("integer".equals(mResourceType)) return resources + ".getInteger(" + resourceName + ")";
        if ("interpolator".equals(mResourceType))  return "android.view.animation.AnimationUtils.loadInterpolator(" + context + ", " + resourceName + ")";
        if ("layout".equals(mResourceType)) return resourceName;
        if ("plurals".equals(mResourceType)) {
            if (getChildren().isEmpty()) {
                return resourceName;
            } else {
                return makeParameterCall(resources, resourceName, "getQuantityString");
            }
        }
        if ("stateListAnimator".equals(mResourceType)) return "android.animation.AnimatorInflater.loadStateListAnimator(" + context + ", " + resourceName + ")";
        if ("string".equals(mResourceType)) return makeParameterCall(resources, resourceName, "getString");
        if ("stringArray".equals(mResourceType)) return resources + ".getStringArray(" + resourceName + ")";
        if ("transition".equals(mResourceType)) return "android.transition.TransitionInflater.from(" + context + ").inflateTransition(" + resourceName + ")";
        if ("typedArray".equals(mResourceType)) return resources + ".obtainTypedArray(" + resourceName + ")";
        final String property = Character.toUpperCase(mResourceType.charAt(0)) +
                mResourceType.substring(1);
        return resources + ".get" + property + "(" + resourceName + ")";

    }

将 BindingAdapter 与资源中的字符串数组结合使用

Using a BindingAdapter with a string-array from the resources

android

arrays

android-resources

android-databinding