Method _updateFocusState

src/material/form-field/form-field.ts:548–566

()

  }

  private _updateFocusState() {
    const controlFocused = this._control.focused;

    // Usually the MDC foundation would call "activateFocus" and "deactivateFocus" whenever
    // certain DOM events are emitted. This is not possible in our implementation of the
    // form field because we support abstract form field controls which are not necessarily
    // of type input, nor do we have a reference to a native form field control element. Instead
    // we handle the focus by checking if the abstract form field control focused state changes.
    if (controlFocused && !this._isFocused) {
      this._isFocused = true;
      this._lineRipple?.activate();
    } else if (!controlFocused && (this._isFocused || this._isFocused === null)) {
      this._isFocused = false;
      this._lineRipple?.deactivate();
    }

    this._elementRef.nativeElement.classList.toggle('mat-focused', controlFocused);
    this._textField?.nativeElement.classList.toggle('mdc-text-field--focused', controlFocused);
  }

  /**
   * The floating label in the docked state needs to account for prefixes. The horizontal offset