Theme support in Anko

[fboldog]

My proposal for theming comes from my example AnkoExtensions.kt and depends on appcompat-v7 ContextThemeWrapper (hidden from public api)

• extending (ViewManager|Context|Activty).ankoView method:

fun wrapContextIfNeeded(ctx: Context,@StyleRes theme: Int): Context {
    return if (theme != 0 && (ctx !is ContextThemeWrapper || ctx.themeResId != theme)) {
        // If the context isn't a ContextThemeWrapper, or it is but does not have
        // the same theme as we need, wrap it in a new wrapper
        ContextThemeWrapper(ctx, theme)
    } else {
        ctx
    }
}

inline fun <T : View> ViewManager.ankoView(@StyleRes theme: Int = 0, factory: (ctx: Context) -> T, init: T.() -> Unit): T {
    val ctx = wrapContextIfNeeded(AnkoInternals.getContext(this), theme)
    val view = factory(ctx)
    view.init()
    AnkoInternals.addView(this, view)
    return view
}

inline fun <T : View> Context.ankoView(@StyleRes theme: Int, factory: (ctx: Context) -> T, init: T.() -> Unit): T {
    val ctx = wrapContextIfNeeded(this, theme)
    val view = factory(ctx)
    view.init()
    AnkoInternals.addView(this, view)
    return view
}

inline fun <reified T : View> ViewManager.customView(@StyleRes theme: Int = 0, init: T.() -> Unit): T {
    return ankoView(theme, { ctx -> AnkoInternals.initiateView(ctx, T::class.java) }) { init() }
}

inline fun <reified T : View> Context.customView(@StyleRes theme: Int = 0, init: T.() -> Unit): T {
    return ankoView(theme, { ctx -> AnkoInternals.initiateView(ctx, T::class.java) }) { init() }
}

inline fun <reified T : View> Activity.customView(@StyleRes theme: Int = 0, init: T.() -> Unit): T {
    return ankoView(theme, { ctx -> AnkoInternals.initiateView(ctx, T::class.java) }) { init() }
}

• extending Views, Layouts like this:

inline fun Activity.verticalLayout(@StyleRes theme: Int = 0): LinearLayout = verticalLayout(theme, {})
inline fun Activity.verticalLayout(@StyleRes theme: Int = 0, init: _LinearLayout.() -> Unit): LinearLayout {
    return ankoView(theme, `$$Anko$Factories$CustomViews`.VERTICAL_LAYOUT_FACTORY, init)
}

inline fun ViewManager.appBarLayout(@StyleRes theme: Int): AppBarLayout = appBarLayout(theme, {})
inline fun ViewManager.appBarLayout(@StyleRes theme: Int, init: _AppBarLayout.() -> Unit): AppBarLayout {
    return ankoView(theme, `$$Anko$Factories$DesignViewGroup`.APP_BAR_LAYOUT) { init() }
}

[BennyWang]

+1

[dbacinski]

@yanex Is it ok? When do you plan to release Anko with this change?

[mvysny]

Working great, thank you. What I'm missing though is the @StyleRes annotation on the theme parameter. This would warn user not to use the R.attr.* values by mistake.

[LouisCAD]

The README.md should be updated to reflect changes about this issue and #16 so we know how to use it.