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getResources().getDrawable() dep

getResources().getDrawable() dep

作者: Xamarin信仰中心 | 来源:发表于2018-10-08 13:47 被阅读8次

    stackoverflow: https://stackoverflow.com/questions/29041027/android-getresources-getdrawable-deprecated-api-22

    You have some options to handle this deprecation the right (and future proof) way, depending on which kind of drawable you are loading:


    1. API 详解

    A) drawables with theme attributes

    ContextCompat.getDrawable(getActivity(), R.drawable.name);
    

    You'll obtain a styled Drawable as your Activity theme instructs.
    This is probably what you need.


    B) drawables without theme attributes

    ResourcesCompat.getDrawable(getResources(), R.drawable.name, null);
    

    You'll get your unstyled drawable the old way. Please note: ResourcesCompat.getDrawable() is not deprecated!


    EXTRA) drawables with theme attributes from another theme

    ResourcesCompat.getDrawable(getResources(), R.drawable.name, anotherTheme);
    

    2. 为什么这个 API deprecated

    API 21 (Android 5.0 Lollipop) 引入了一些新的主题属性 (new theme attributes),例如 android:colorAccent, 它修改了包含对那些新主题属性值的引用的 drawable 的外观. AppCompat 库为您处理 Lollipop 前后绘制样式。

    如果使用废弃的 API getDrawable() 方法来获取具有主题属性的可绘制资源,您将获得部分样式的 drawablelogcat 警告。您可以在 API 22 中看到这个 android.content.res.Resources源代码:

    API 21 (Android 5.0 Lollipop) introduced some new theme attributes such as android:colorAccent that modify the appearance of drawables that hold references to those new theme attributes values.The AppCompat library handles pre and post-Lollipop drawable styling for you.
    If you do use the deprecated getDrawable() method to obtain a drawable resource with theme attributes, you will get a partially-styled drawable and a logcat warning.You can see this in API 22 android.content.res.Resources source code:

    @Deprecated
    @Nullable
    public Drawable getDrawable(int id) throws NotFoundException {
        final Drawable d = getDrawable(id, null);
        if (d != null && d.canApplyTheme()) {
            Log.w(TAG, "Drawable " + getResourceName(id) + " has unresolved theme "
                    + "attributes! Consider using Resources.getDrawable(int, Theme) or "
                    + "Context.getDrawable(int).", new RuntimeException());
        }
        return d;
    }
    

    3. 解决方案

    使用以下的 API

    ContextCompat.getDrawable(context, R.drawable.***)
    

    这个 API 等同于:

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        return resources.getDrawable(id, context.getTheme());
    } else {
        return resources.getDrawable(id);
    }
    

    API 21 开始,我们应该使用 getDrawable(int, Theme) 方法而不是 getDrawable(int),因为它允许我们获取与给定屏幕密度/主题的特定资源 ID 关联的可绘制对象

    直接调用 deprecated 的 getDrawable(int)方法等同于调用 getDrawable(int, null)

    4. 参考链接

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