Merge pull request #4190 from NativeScript/EddyVerbruggen-eddyverbruggen/issue-3614-text-maxlength-property

Implemented feature request: TextField `maxLength` property support.

tns-core-modules/ui/editable-text-base/editable-text-base-common.ts

@@ -13,6 +13,7 @@ export abstract class EditableTextBase extends TextBase implements EditableTextB
     public editable: boolean;
     public autocorrect: boolean;
     public hint: string;
+    public maxLength: number;
 
     public abstract dismissSoftInput();
     public abstract _setInputType(inputType: number): void;
@@ -49,4 +50,7 @@ export const autocorrectProperty = new Property<EditableTextBase, boolean>({ nam
 autocorrectProperty.register(EditableTextBase);
 
 export const hintProperty = new Property<EditableTextBase, string>({ name: "hint", defaultValue: "" });
-hintProperty.register(EditableTextBase);
+hintProperty.register(EditableTextBase);
+
+export const maxLengthProperty = new Property<EditableTextBase, number>({ name: "maxLength", defaultValue: Number.POSITIVE_INFINITY });
+maxLengthProperty.register(EditableTextBase);

tns-core-modules/ui/editable-text-base/editable-text-base.android.ts

@@ -2,7 +2,7 @@
     EditableTextBase as EditableTextBaseCommon, keyboardTypeProperty,
     returnKeyTypeProperty, editableProperty,
     autocapitalizationTypeProperty, autocorrectProperty, hintProperty,
-    textProperty, placeholderColorProperty, Color, textTransformProperty
+    textProperty, placeholderColorProperty, Color, textTransformProperty, maxLengthProperty
 } from "./editable-text-base-common";
 
 import { ad } from "../../utils/utils";
@@ -429,4 +429,23 @@ export abstract class EditableTextBase extends EditableTextBaseCommon {
     [textTransformProperty.setNative](value: "default") {
         //
     }
-}
+
+    [maxLengthProperty.setNative](value: number) {
+        let lengthFilter = new android.text.InputFilter.LengthFilter(+value);
+        let filters = this.nativeView.getFilters();
+        let newFilters = [];
+
+        // retain existing filters
+        for (let i = 0; i < filters.length; i++) {
+            newFilters.push(filters[i]);
+            // update an existing length filter
+            if (filters[i] instanceof android.text.InputFilter.LengthFilter) {
+                filters[i] = lengthFilter;
+                return;
+            }
+        }
+        // no current length filter found, so add it
+        newFilters.push(lengthFilter);
+        this.nativeView.setFilters(newFilters);
+    }
+}

tns-core-modules/ui/editable-text-base/editable-text-base.d.ts

@@ -45,6 +45,11 @@ export class EditableTextBase extends TextBase {
      */
     hint: string;
 
+    /**
+     * Limits input to a certain number of characters.
+     */
+    maxLength: number;
+
     /**
      * Hides the soft input method, ususally a soft keyboard.
      */
@@ -71,6 +76,7 @@ export const autocapitalizationTypeProperty: Property<EditableTextBase, Autocapi
 export const autocorrectProperty: Property<EditableTextBase, boolean>;
 export const hintProperty: Property<EditableTextBase, string>;
 export const placeholderColorProperty: CssProperty<Style, Color>;
+export const maxLengthProperty: Property<EditableTextBase, number>;
 
 //@private
 /**

tns-core-modules/ui/text-field/text-field.ios.ts

@@ -1,5 +1,5 @@
 import { 
-    TextFieldBase, secureProperty, textProperty, hintProperty, colorProperty, placeholderColorProperty, 
+    TextFieldBase, secureProperty, textProperty, hintProperty, colorProperty, placeholderColorProperty,
     Length, paddingTopProperty, paddingRightProperty, paddingBottomProperty, paddingLeftProperty, _updateCharactersInRangeReplacementString, Color, layout
 } from "./text-field-common";
 
@@ -67,6 +67,13 @@ class UITextFieldDelegateImpl extends NSObject implements UITextFieldDelegate {
     public textFieldShouldChangeCharactersInRangeReplacementString(textField: UITextField, range: NSRange, replacementString: string): boolean {
         const owner = this._owner.get();
         if (owner) {
+            const delta = replacementString.length - range.length;
+            if (delta > 0) {
+                if (textField.text.length + delta > owner.maxLength) {
+                    return false;
+                }
+            }
+
             if (owner.updateTextTrigger === "textChanged") {
                 if (textField.secureTextEntry && this.firstEdit) {
                     textProperty.nativeValueChange(owner, replacementString);

tns-core-modules/ui/text-view/text-view.ios.ts

@@ -59,8 +59,17 @@ class UITextViewDelegateImpl extends NSObject implements UITextViewDelegate {
 
     public textViewShouldChangeTextInRangeReplacementText(textView: UITextView, range: NSRange, replacementString: string): boolean {
         const owner = this._owner.get();
-        if (owner && owner.formattedText) {
+        if (owner) {
-            _updateCharactersInRangeReplacementString(owner.formattedText, range.location, range.length, replacementString);
+            const delta = replacementString.length - range.length;
+            if (delta > 0) {
+                if (textView.text.length + delta > owner.maxLength) {
+                    return false;
+                }
+            }
+
+            if (owner.formattedText) {
+                _updateCharactersInRangeReplacementString(owner.formattedText, range.location, range.length, replacementString);
+            }
         }
 
         return true;