<div class="radio-buttons-widget"
     [class.radio-buttons-widget__invalid]="!field.isValid">
    <label class="radio-buttons-widget__label" [attr.for]="field.id">{{field.name}}</label>
    <div *ngFor="let opt of field.options">
        <label [attr.for]="opt.id" class="mdl-radio mdl-js-radio">
            <input type="radio"
                   class="mdl-radio__button"
                   [checked]="field.value === opt.id"
                   [attr.id]="opt.id"
                   [attr.name]="field.id"
                   [attr.value]="opt.id"
                   [disabled]="field.readOnly"
                   (click)="field.value = opt.id">
            <span class="mdl-radio__label">{{opt.name}}</span>
        </label>
    </div>
    <span *ngIf="field.validationSummary" class="mdl-textfield__error">{{field.validationSummary}}</span>
</div>

<div class="radio-buttons-widget"
     [class.radio-buttons-widget__invalid]="!field.isValid" [id]="field.id">
    <label class="radio-buttons-widget__label" [attr.for]="field.id">{{field.name}}</label>
    <div *ngFor="let opt of field.options">
        <label [id]="opt.id" [attr.for]="field.id + '-' + opt.id" class="mdl-radio mdl-js-radio">
            <input type="radio"
                   class="mdl-radio__button"
                   [checked]="field.value === opt.id"
                   [attr.id]="field.id + '-' + opt.id"
                   [attr.name]="field.id"
                   [attr.value]="opt.id"
                   [disabled]="field.readOnly"
                   (click)="field.value = opt.id">
            <span class="mdl-radio__label">{{opt.name}}</span>
        </label>
    </div>
    <span *ngIf="field.validationSummary" class="mdl-textfield__error">{{field.validationSummary}}</span>
</div>

Fix index for multiple radio buttons
Fix index for multiple radio buttons
