NativeScript/tns-core-modules/ui/layouts/grid-layout/grid-layout.android.ts

import {
    GridLayoutBase, ItemSpec as ItemSpecBase, View, layout,
    rowProperty, columnProperty, rowSpanProperty, columnSpanProperty, GridUnitType
} from "./grid-layout-common";

export * from "./grid-layout-common";

function makeNativeSetter<T>(setter: (lp: org.nativescript.widgets.CommonLayoutParams, value: T) => void) {
    return function(this: View, value: T) {
        const nativeView: android.view.View = this.nativeView;
        const lp = nativeView.getLayoutParams() || new org.nativescript.widgets.CommonLayoutParams();
        if (lp instanceof org.nativescript.widgets.CommonLayoutParams) {
            setter(lp, value);
            nativeView.setLayoutParams(lp);
        }
    }
}

View.prototype[rowProperty.setNative] = makeNativeSetter<number>((lp, value) => lp.row = value);
View.prototype[columnProperty.setNative] = makeNativeSetter<number>((lp, value) => lp.column = value);
View.prototype[rowSpanProperty.setNative] = makeNativeSetter<number>((lp, value) => lp.rowSpan = value);
View.prototype[columnSpanProperty.setNative] = makeNativeSetter<number>((lp, value) => lp.columnSpan = value);

function createNativeSpec(itemSpec: ItemSpec): org.nativescript.widgets.ItemSpec {
    switch (itemSpec.gridUnitType) {
        case GridUnitType.AUTO:
            return new org.nativescript.widgets.ItemSpec(itemSpec.value, org.nativescript.widgets.GridUnitType.auto);

        case GridUnitType.STAR:
            return new org.nativescript.widgets.ItemSpec(itemSpec.value, org.nativescript.widgets.GridUnitType.star);

        case GridUnitType.PIXEL:
            return new org.nativescript.widgets.ItemSpec(itemSpec.value * layout.getDisplayDensity(), org.nativescript.widgets.GridUnitType.pixel);

        default:
            throw new Error("Invalid gridUnitType: " + itemSpec.gridUnitType);
    }
}

export class ItemSpec extends ItemSpecBase {
    nativeSpec: org.nativescript.widgets.ItemSpec;

    public get actualLength(): number {
        if (this.nativeSpec) {
            return Math.round(this.nativeSpec.getActualLength() / layout.getDisplayDensity());
        }

        return 0;
    }
}

export class GridLayout extends GridLayoutBase {
    nativeView: org.nativescript.widgets.GridLayout;

    public createNativeView() {
        return new org.nativescript.widgets.GridLayout(this._context);
    }

    public initNativeView(): void {
        super.initNativeView();
        // Update native GridLayout
        this.rowsInternal.forEach((itemSpec: ItemSpec, index, rows) => { this._onRowAdded(itemSpec); }, this);
        this.columnsInternal.forEach((itemSpec: ItemSpec, index, rows) => { this._onColumnAdded(itemSpec); }, this);
    }

    public resetNativeView() {
        // Update native GridLayout
        for (let i = this.rowsInternal.length; i--; i >= 0) {
            const itemSpec = <ItemSpec>this.rowsInternal[i];
            this._onRowRemoved(itemSpec, i);
        }

        for (let i = this.columnsInternal.length; i--; i >= 0) {
            const itemSpec = <ItemSpec>this.columnsInternal[i];
            this._onColumnRemoved(itemSpec, i);
        }

        super.resetNativeView();
    }

    public _onRowAdded(itemSpec: ItemSpec) {
        if (this.nativeView) {
            const nativeSpec = createNativeSpec(itemSpec);
            itemSpec.nativeSpec = nativeSpec;
            this.nativeView.addRow(nativeSpec);
        }
    }

    public _onColumnAdded(itemSpec: ItemSpec) {
        if (this.nativeView) {
            const nativeSpec = createNativeSpec(itemSpec);
            itemSpec.nativeSpec = nativeSpec;
            this.nativeView.addColumn(nativeSpec);
        }
    }

    public _onRowRemoved(itemSpec: ItemSpec, index: number) {
        itemSpec.nativeSpec = null;
        if (this.nativeView) {
            this.nativeView.removeRowAt(index);
        }
    }

    public _onColumnRemoved(itemSpec: ItemSpec, index: number) {
        itemSpec.nativeSpec = null;
        if (this.nativeView) {
            this.nativeView.removeColumnAt(index);
        }
    }

    protected invalidate(): void {
        // No need to request layout for android because it will be done in the native call.
    }
}