also implement for textview

Author: Anthony Salamanca

src/textview/textview.android.ts

@@ -4,6 +4,7 @@ import {
     floatingColorProperty,
     floatingInactiveColorProperty,
     floatingProperty,
+    helperColorProperty,
     helperProperty,
     maxLengthProperty,
     strokeColorProperty,
@@ -104,6 +105,10 @@ export class TextView extends TextViewBase {
         this.layoutView.setHint(text);
     }
 
+    [helperColorProperty.setNative](value) {
+        const color = value instanceof Color ? value.android : value;
+        this.layoutView.setHelperTextColor(android.content.res.ColorStateList.valueOf(color));
+    }
     [placeholderColorProperty.setNative](value: Color) {
         const placeholderColor = value instanceof Color ? value.android : value;
         const floatingColor = this.floatingColor instanceof Color ? this.floatingColor.android : placeholderColor;

src/textview/textview.common.ts

@@ -7,6 +7,7 @@ export abstract class TextViewBase extends NSTextView {
     abstract clearFocus();
 
     @cssProperty helper: string;
+    @cssProperty helperColor: Color;
     @cssProperty maxLength: number;
     @cssProperty errorColor: Color;
     @cssProperty floating: boolean;

src/textview/textview.d.ts

@@ -12,6 +12,7 @@ export class TextView extends EditableTextBase {
     nativeViewProtected: any;
 
     helper: string;
+    helperColor: Color;
     maxLength: number;
     errorColor: Color;
     floating: boolean;

src/textview/textview.ios.ts

@@ -6,6 +6,7 @@ import {
     floatingColorProperty,
     floatingInactiveColorProperty,
     floatingProperty,
+    helperColorProperty,
     helperProperty,
     maxLengthProperty,
     strokeColorProperty,
@@ -312,6 +313,11 @@ export class TextView extends TextViewBase {
     [helperProperty.setNative](value: string) {
         this._controller.helperText = value;
     }
+    [helperColorProperty.setNative](value: string | Color) {
+        const temp = typeof value === 'string' ? new Color(value) : value;
+        const color: UIColor = temp.ios;
+        this._controller.leadingUnderlineLabelTextColor = color;
+    }
     [maxLengthProperty.setNative](value: number) {
         this._controller.characterCountMax = value;
     }