import { QueryList, ChangeDetectorRef, AfterContentInit } from '@angular/core';
import { ControlValueAccessor } from '@angular/forms';
import { NpRadioButton } from './radio-button.component';
/**
 * 单选按钮组 - 此标签作为一个单选按钮分组使用，内部可包含多个单选按钮组件{@link NpRadioButton|RadioButton}。
 *
 * <example-url>https://stackblitz.com/edit/np-radio-button-sample?embed=1&file=src/app/app.component.html</example-url>
 */
export declare class NpRadioGroup implements AfterContentInit, ControlValueAccessor {
    private _changeDetector;
    /**
     * Value for the radio-group. Should equal the value of the selected radio button if there is
     * a corresponding radio button with a matching value. If there is not such a corresponding
     * radio button, this value persists to be applied in case a new radio button is added with a
     * matching value.
     */
    value: any;
    constructor(_changeDetector: ChangeDetectorRef);
    private _selected;
    private _value;
    /**单选框分组标签 */
    label: string;
    /**单选框分组是否必填，如为true，则标签前有红色星号，false则没有。注：此属性不作为校验属性，仅展示星号与否。 */
    isRequired: boolean;
    _radios: QueryList<NpRadioButton>;
    _controlValueAccessorChangeFn: (value: any) => void;
    onTouched: () => any;
    ngAfterContentInit(): void;
    /**
   * Sets the model value. Implemented as part of ControlValueAccessor.
   * @param value
   */
    writeValue(value: any): void;
    /**
     * Registers a callback to be triggered when the model value changes.
     * Implemented as part of ControlValueAccessor.
     * @param fn Callback to be registered.
     */
    registerOnChange(fn: (value: any) => void): void;
    /**
     * Registers a callback to be triggered when the control is touched.
     * Implemented as part of ControlValueAccessor.
     * @param fn Callback to be registered.
     */
    registerOnTouched(fn: any): void;
    _checkSelectedRadioButton(): void;
    /** Updates the `selected` radio button from the internal _value state. */
    private _updateSelectedRadioFromValue;
}