NativeScript/nativescript-core/ui/tab-navigation-base/tab-strip-item/tab-strip-item.ts

// Types
import { TabStripItem as TabStripItemDefinition } from ".";
import { PropertyChangeData } from "../../../data/observable";
import { TabNavigationBase } from "../tab-navigation-base";
import { TabStrip } from "../tab-strip";
import { Image } from "../../image/image";
import { Label } from "../../label/label";
import { Color } from "../../../color";
import { AddChildFromBuilder } from "../../core/view";

// Requires
import {
    View, ViewBase, CSSType, backgroundColorProperty, backgroundInternalProperty, PseudoClassHandler
} from "../../core/view";
import { Tabs } from "../../tabs";
import { isIOS } from "../../../platform";

export * from "../../core/view";
export const traceCategory = "TabView";

@CSSType("TabStripItem")
export class TabStripItem extends View implements TabStripItemDefinition, AddChildFromBuilder {
    public static tapEvent = "tap";
    public static selectEvent = "select";
    public static unselectEvent = "unselect";

    public image: Image;
    public label: Label;

    private _title: string;
    private _iconSource: string;

    private _highlightedHandler: () => void;
    private _normalHandler: () => void;

    private _labelColorHandler: (args: PropertyChangeData) => void;
    private _labelFontHandler: (args: PropertyChangeData) => void;
    private _labelTextTransformHandler: (args: PropertyChangeData) => void;
    private _labelTextHandler: (args: PropertyChangeData) => void;

    private _imageColorHandler: (args: PropertyChangeData) => void;
    private _imageFontHandler: (args: PropertyChangeData) => void;
    private _imageSrcHandler: (args: PropertyChangeData) => void;

    get title(): string {
        if (this.isLoaded) {
            return this.label.text;
        }

        return this._title;
    }

    set title(value: string) {
        this._title = value;

        if (this.isLoaded) {
            this.label.text = value;
        }
    }

    get iconSource(): string {
        if (this.isLoaded) {
            return this.image.src;
        }

        return this._iconSource;
    }

    set iconSource(value: string) {
        this._iconSource = value;

        if (this.isLoaded) {
            this.image.src = value;
        }
    }

    public onLoaded() {
        if (!this.image) {
            const image = new Image();
            image.src = this.iconSource;
            this.image = image;
            this._addView(this.image);
        }

        if (!this.label) {
            const label = new Label();
            label.text = this.title;
            this.label = label;
            this._addView(this.label);
        }

        super.onLoaded();

        this._labelColorHandler = this._labelColorHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && tabStripParent.setTabBarItemColor(this, args.value);
        });
        this.label.style.on("colorChange", this._labelColorHandler);

        this._labelFontHandler = this._labelFontHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && tabStripParent.setTabBarItemFontInternal(this, args.value);
        });
        this.label.style.on("fontInternalChange", this._labelFontHandler);

        this._labelTextTransformHandler = this._labelTextTransformHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && tabStripParent.setTabBarItemTextTransform(this, args.value);
        });
        this.label.style.on("textTransformChange", this._labelTextTransformHandler);

        this._labelTextHandler = this._labelTextHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && tabStripParent.setTabBarItemTitle(this, args.value);
        });
        this.label.on("textChange", this._labelTextHandler);

        this._imageColorHandler = this._imageColorHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && (<any>tabStripParent).setTabBarIconColor(this, args.value);
        });
        this.image.style.on("colorChange", this._imageColorHandler);

        this._imageFontHandler = this._imageFontHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && (<any>tabStripParent).setTabBarIconColor(this, args.value);
        });
        this.image.style.on("fontInternalChange", this._imageFontHandler);

        this._imageSrcHandler = this._imageSrcHandler || ((args: PropertyChangeData) => {
            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;

            return tabStripParent && (<any>tabStripParent).setTabBarIconColor(this, args.value);
        });
        this.image.on("srcChange", this._imageSrcHandler);
    }

    public onUnloaded() {
        super.onUnloaded();

        this.label.style.off("colorChange", this._labelColorHandler);
        this.label.style.off("fontInternalChange", this._labelFontHandler);
        this.label.style.off("textTransformChange", this._labelTextTransformHandler);
        this.label.style.off("textChange", this._labelTextHandler);

        this.image.style.off("colorChange", this._imageColorHandler);
        this.image.style.off("fontInternalChange", this._imageFontHandler);
        this.image.style.off("srcChange", this._imageSrcHandler);
    }

    public eachChild(callback: (child: ViewBase) => boolean) {
        if (this.label) {
            callback(this.label);
        }

        if (this.image) {
            callback(this.image);
        }
    }

    public _addChildFromBuilder(name: string, value: any): void {
        if (name === "Image") {
            this.image = <Image>value;
            this.iconSource = (<Image>value).src;
            this._addView(value);
            // selectedIndexProperty.coerce(this);
        }

        if (name === "Label") {
            this.label = <Label>value;
            this.title = (<Label>value).text;
            this._addView(value);
            // selectedIndexProperty.coerce(this);
        }
    }

    public requestLayout(): void {
        // Default implementation for non View instances (like TabViewItem).
        const parent = this.parent;
        if (parent) {
            parent.requestLayout();
        }
    }

    @PseudoClassHandler("normal", "highlighted", "pressed", "active")
    _updateTabStateChangeHandler(subscribe: boolean) {
        if (subscribe) {
            this._highlightedHandler = this._highlightedHandler || (() => {
                this._goToVisualState("highlighted");
            });

            this._normalHandler = this._normalHandler || (() => {
                this._goToVisualState("normal");
            });

            this.on(TabStripItem.selectEvent, this._highlightedHandler);
            this.on(TabStripItem.unselectEvent, this._normalHandler);

            const parent = <TabStrip>this.parent;
            const tabStripParent = parent && <TabNavigationBase>parent.parent;
            if ((<any>this).index === tabStripParent.selectedIndex &&
                !(isIOS && tabStripParent instanceof Tabs)) {
                this._goToVisualState("highlighted");
            }
        } else {
            this.off(TabStripItem.selectEvent, this._highlightedHandler);
            this.off(TabStripItem.unselectEvent, this._normalHandler);
        }
    }

    [backgroundColorProperty.getDefault](): Color {
        const parent = <TabStrip>this.parent;
        const tabStripParent = parent && <TabNavigationBase>parent.parent;

        return tabStripParent && tabStripParent.getTabBarBackgroundColor();
    }
    [backgroundColorProperty.setNative](value: Color) {
        const parent = <TabStrip>this.parent;
        const tabStripParent = parent && <TabNavigationBase>parent.parent;

        return tabStripParent && tabStripParent.setTabBarItemBackgroundColor(this, value);
    }

    [backgroundInternalProperty.getDefault](): any {
        return null;
    }
    [backgroundInternalProperty.setNative](value: any) {
        // disable the background CSS properties
    }
}