NativeScript/nativescript-core/ui/text-base/formatted-string.ts

import { FormattedString as FormattedStringDefinition } from "./formatted-string";
import { Span } from "./span";
import { Observable, PropertyChangeData } from "../../data/observable";
import { ObservableArray, ChangedData } from "../../data/observable-array";
import { ViewBase, AddArrayFromBuilder, AddChildFromBuilder } from "../core/view";
import { Color } from "../../color";
import { FontStyle, FontWeight } from "../styling/font";
import { TextDecoration } from "../text-base";

export { Span };

export module knownCollections {
    export const spans = "spans";
}

export class FormattedString extends ViewBase implements FormattedStringDefinition, AddArrayFromBuilder, AddChildFromBuilder {
    private _spans: ObservableArray<Span>;

    constructor() {
        super();
        this._spans = new ObservableArray<Span>();
        this._spans.addEventListener(ObservableArray.changeEvent, this.onSpansCollectionChanged, this);
    }

    get fontFamily(): string {
        return this.style.fontFamily;
    }
    set fontFamily(value: string) {
        this.style.fontFamily = value;
    }

    get fontSize(): number {
        return this.style.fontSize;
    }
    set fontSize(value: number) {
        this.style.fontSize = value;
    }

    get fontStyle(): FontStyle {
        return this.style.fontStyle;
    }
    set fontStyle(value: FontStyle) {
        this.style.fontStyle = value;
    }

    get fontWeight(): FontWeight {
        return this.style.fontWeight;
    }
    set fontWeight(value: FontWeight) {
        this.style.fontWeight = value;
    }

    get textDecoration(): TextDecoration {
        return this.style.textDecoration;
    }
    set textDecoration(value: TextDecoration) {
        this.style.textDecoration = value;
    }

    get color(): Color {
        return this.style.color;
    }
    set color(value: Color) {
        this.style.color = value;
    }

    get backgroundColor(): Color {
        return this.style.backgroundColor;
    }
    set backgroundColor(value: Color) {
        this.style.backgroundColor = value;
    }

    get spans(): ObservableArray<Span> {
        if (!this._spans) {
            this._spans = new ObservableArray<Span>();
        }

        return this._spans;
    }

    public toString(): string {
        let result = "";
        for (let i = 0, length = this._spans.length; i < length; i++) {
            result += this._spans.getItem(i).text;
        }

        return result;
    }

    public _addArrayFromBuilder(name: string, value: Array<any>) {
        if (name === knownCollections.spans) {
            this.spans.push(value);
        }
    }

    public _addChildFromBuilder(name: string, value: any): void {
        if (value instanceof Span) {
            this.spans.push(value);
        }
    }

    private onSpansCollectionChanged(eventData: ChangedData<Span>) {
        if (eventData.addedCount > 0) {
            for (let i = 0; i < eventData.addedCount; i++) {
                const span = (<ObservableArray<Span>>eventData.object).getItem(eventData.index + i);

                // First add to logical tree so that inherited properties are set.
                this._addView(span);

                // Then attach handlers - we skip the first nofitication because
                // we raise change for the whole instance.
                this.addPropertyChangeHandler(span);
            }
        }

        if (eventData.removed && eventData.removed.length > 0) {
            for (let p = 0; p < eventData.removed.length; p++) {
                const span = eventData.removed[p];

                // First remove handlers so that we don't listen for changes
                // on inherited properties.
                this.removePropertyChangeHandler(span);

                // Then remove the element.
                this._removeView(span);
            }
        }

        this.notifyPropertyChange(".", this);
    }

    private addPropertyChangeHandler(span: Span) {
        const style = span.style;
        span.on(Observable.propertyChangeEvent, this.onPropertyChange, this);
        style.on("fontFamilyChange", this.onPropertyChange, this);
        style.on("fontSizeChange", this.onPropertyChange, this);
        style.on("fontStyleChange", this.onPropertyChange, this);
        style.on("fontWeightChange", this.onPropertyChange, this);
        style.on("textDecorationChange", this.onPropertyChange, this);
        style.on("colorChange", this.onPropertyChange, this);
        style.on("backgroundColorChange", this.onPropertyChange, this);
    }

    private removePropertyChangeHandler(span: Span) {
        const style = span.style;
        span.off(Observable.propertyChangeEvent, this.onPropertyChange, this);
        style.off("fontFamilyChange", this.onPropertyChange, this);
        style.off("fontSizeChange", this.onPropertyChange, this);
        style.off("fontStyleChange", this.onPropertyChange, this);
        style.off("fontWeightChange", this.onPropertyChange, this);
        style.off("textDecorationChange", this.onPropertyChange, this);
        style.off("colorChange", this.onPropertyChange, this);
        style.off("backgroundColorChange", this.onPropertyChange, this);
    }

    private onPropertyChange(data: PropertyChangeData) {
        this.notifyPropertyChange(data.propertyName, this);
    }

    eachChild(callback: (child: ViewBase) => boolean): void {
        this.spans.forEach((v, i, arr) => callback(v));
    }
}