obscureText and enableInteractiveSelection defaults (#24527)

* obscureText true defaults to disabling selection

* Tests and comments for selectable text field

* Improve selection docs

* Refactor so that all enableInteractiveSelection params are null by default, delegate to selectionEnabled

* Fix selection param macros

packages/flutter/lib/src/material/text_field.dart

@@ -92,8 +92,8 @@ class TextField extends StatefulWidget {
   /// switch to the [decoration.errorStyle] when the limit is exceeded.
   ///
   /// The [textAlign], [autofocus], [obscureText], [autocorrect],
-  /// [maxLengthEnforced], [scrollPadding], [maxLines], [maxLength],
-  /// and [enableInteractiveSelection] arguments must not be null.
+  /// [maxLengthEnforced], [scrollPadding], [maxLines], and [maxLength]
+  /// arguments must not be null.
   ///
   /// See also:
   ///
@@ -126,7 +126,7 @@ class TextField extends StatefulWidget {
     this.cursorColor,
     this.keyboardAppearance,
     this.scrollPadding = const EdgeInsets.all(20.0),
-    this.enableInteractiveSelection = true,
+    this.enableInteractiveSelection,
     this.onTap,
   }) : assert(textAlign != null),
        assert(autofocus != null),
@@ -137,7 +137,6 @@ class TextField extends StatefulWidget {
        assert(maxLines == null || maxLines > 0),
        assert(maxLength == null || maxLength > 0),
        keyboardType = keyboardType ?? (maxLines == 1 ? TextInputType.text : TextInputType.multiline),
-       assert(enableInteractiveSelection != null),
        super(key: key);
 
   /// Controls the text being edited.
@@ -334,6 +333,11 @@ class TextField extends StatefulWidget {
   /// {@macro flutter.widgets.editableText.enableInteractiveSelection}
   final bool enableInteractiveSelection;
 
+  /// {@macro flutter.rendering.editable.selectionEnabled}
+  bool get selectionEnabled {
+    return enableInteractiveSelection ?? !obscureText;
+  }
+
   /// Called when the user taps on this textfield.
   ///
   /// The textfield builds a [GestureDetector] to handle input events like tap,
@@ -508,7 +512,7 @@ class _TextFieldState extends State<TextField> with AutomaticKeepAliveClientMixi
   }
 
   void _handleTap() {
-    if (widget.enableInteractiveSelection)
+    if (widget.selectionEnabled)
       _renderEditable.handleTap();
     _requestKeyboard();
     _confirmCurrentSplash();
@@ -521,7 +525,7 @@ class _TextFieldState extends State<TextField> with AutomaticKeepAliveClientMixi
   }
 
   void _handleLongPress() {
-    if (widget.enableInteractiveSelection)
+    if (widget.selectionEnabled)
       _renderEditable.handleLongPress();
     _confirmCurrentSplash();
   }
@@ -599,7 +603,7 @@ class _TextFieldState extends State<TextField> with AutomaticKeepAliveClientMixi
         autocorrect: widget.autocorrect,
         maxLines: widget.maxLines,
         selectionColor: themeData.textSelectionColor,
-        selectionControls: widget.enableInteractiveSelection
+        selectionControls: widget.selectionEnabled
           ? (themeData.platform == TargetPlatform.iOS
              ? cupertinoTextSelectionControls
              : materialTextSelectionControls)

packages/flutter/lib/src/rendering/editable.dart

@@ -122,8 +122,6 @@ class RenderEditable extends RenderBox {
   ///
   /// The [offset] is required and must not be null. You can use [new
   /// ViewportOffset.zero] if you have no need for scrolling.
-  ///
-  /// The [enableInteractiveSelection] argument must not be null.
   RenderEditable({
     TextSpan text,
     @required TextDirection textDirection,
@@ -143,7 +141,7 @@ class RenderEditable extends RenderBox {
     Locale locale,
     double cursorWidth = 1.0,
     Radius cursorRadius,
-    bool enableInteractiveSelection = true,
+    bool enableInteractiveSelection,
     @required this.textSelectionDelegate,
   }) : assert(textAlign != null),
        assert(textDirection != null, 'RenderEditable created without a textDirection.'),
@@ -152,7 +150,6 @@ class RenderEditable extends RenderBox {
        assert(offset != null),
        assert(ignorePointer != null),
        assert(obscureText != null),
-       assert(enableInteractiveSelection != null),
        assert(textSelectionDelegate != null),
        _textPainter = TextPainter(
          text: text,
@@ -715,6 +712,22 @@ class RenderEditable extends RenderBox {
     markNeedsSemanticsUpdate();
   }
 
+  /// {@template flutter.rendering.editable.selectionEnabled}
+  /// True if interactive selection is enabled based on the values of
+  /// [enableInteractiveSelection] and [obscureText].
+  ///
+  /// By default [enableInteractiveSelection] is null, obscureText is false,
+  /// and this method returns true.
+  /// If [enableInteractiveSelection] is null and obscureText is true, then this
+  /// method returns false. This is the common case for password fields.
+  /// If [enableInteractiveSelection] is non-null then its value is returned. An
+  /// app might set it to true to enable interactive selection for a password
+  /// field, or to false to unconditionally disable interactive selection.
+  /// {@endtemplate}
+  bool get selectionEnabled {
+    return enableInteractiveSelection ?? !obscureText;
+  }
+
   @override
   void describeSemanticsConfiguration(SemanticsConfiguration config) {
     super.describeSemanticsConfiguration(config);
@@ -728,10 +741,10 @@ class RenderEditable extends RenderBox {
       ..isFocused = hasFocus
       ..isTextField = true;
 
-    if (hasFocus && enableInteractiveSelection)
+    if (hasFocus && selectionEnabled)
       config.onSetSelection = _handleSetSelection;
 
-    if (enableInteractiveSelection && _selection?.isValid == true) {
+    if (selectionEnabled && _selection?.isValid == true) {
       config.textSelection = _selection;
       if (_textPainter.getOffsetBefore(_selection.extentOffset) != null) {
         config

packages/flutter/lib/src/widgets/editable_text.dart

@@ -183,8 +183,7 @@ class EditableText extends StatefulWidget {
   /// default to [TextInputType.multiline].
   ///
   /// The [controller], [focusNode], [style], [cursorColor], [textAlign],
-  /// [rendererIgnoresPointer], and [enableInteractiveSelection] arguments must
-  /// not be null.
+  /// [rendererIgnoresPointer] arguments must not be null.
   EditableText({
     Key key,
     @required this.controller,
@@ -214,7 +213,7 @@ class EditableText extends StatefulWidget {
     this.cursorRadius,
     this.scrollPadding = const EdgeInsets.all(20.0),
     this.keyboardAppearance = Brightness.light,
-    this.enableInteractiveSelection = true,
+    this.enableInteractiveSelection,
   }) : assert(controller != null),
        assert(focusNode != null),
        assert(obscureText != null),
@@ -226,7 +225,6 @@ class EditableText extends StatefulWidget {
        assert(autofocus != null),
        assert(rendererIgnoresPointer != null),
        assert(scrollPadding != null),
-       assert(enableInteractiveSelection != null),
        keyboardType = keyboardType ?? (maxLines == 1 ? TextInputType.text : TextInputType.multiline),
        inputFormatters = maxLines == 1
            ? (
@@ -469,6 +467,11 @@ class EditableText extends StatefulWidget {
   /// Defaults to false, resulting in a typical blinking cursor.
   static bool debugDeterministicCursor = false;
 
+  /// {@macro flutter.rendering.editable.selectionEnabled}
+  bool get selectionEnabled {
+    return enableInteractiveSelection ?? !obscureText;
+  }
+
   @override
   EditableTextState createState() => EditableTextState();
 
@@ -929,19 +932,19 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   VoidCallback _semanticsOnCopy(TextSelectionControls controls) {
-    return widget.enableInteractiveSelection && _hasFocus && controls?.canCopy(this) == true
+    return widget.selectionEnabled && _hasFocus && controls?.canCopy(this) == true
       ? () => controls.handleCopy(this)
       : null;
   }
 
   VoidCallback _semanticsOnCut(TextSelectionControls controls) {
-    return widget.enableInteractiveSelection && _hasFocus && controls?.canCut(this) == true
+    return widget.selectionEnabled && _hasFocus && controls?.canCut(this) == true
       ? () => controls.handleCut(this)
       : null;
   }
 
   VoidCallback _semanticsOnPaste(TextSelectionControls controls) {
-    return widget.enableInteractiveSelection &&_hasFocus && controls?.canPaste(this) == true
+    return widget.selectionEnabled &&_hasFocus && controls?.canPaste(this) == true
       ? () => controls.handlePaste(this)
       : null;
   }
@@ -1050,11 +1053,10 @@ class _Editable extends LeafRenderObjectWidget {
     this.rendererIgnoresPointer = false,
     this.cursorWidth,
     this.cursorRadius,
-    this.enableInteractiveSelection = true,
+    this.enableInteractiveSelection,
     this.textSelectionDelegate,
   }) : assert(textDirection != null),
        assert(rendererIgnoresPointer != null),
-       assert(enableInteractiveSelection != null),
        super(key: key);
 
   final TextSpan textSpan;

packages/flutter/test/material/text_field_test.dart

@@ -658,6 +658,66 @@ void main() {
     // End the test here to ensure the animation is properly disposed of.
   });
 
+  testWidgets('An obscured TextField is not selectable by default', (WidgetTester tester) async {
+    // This is a regression test for
+    // https://github.com/flutter/flutter/issues/24100
+
+    final TextEditingController controller = TextEditingController();
+    Widget buildFrame(bool obscureText, bool enableInteractiveSelection) {
+      return overlay(
+        child: TextField(
+          controller: controller,
+          obscureText: obscureText,
+          enableInteractiveSelection: enableInteractiveSelection,
+        ),
+      );
+    }
+
+    // Obscure text and don't enable or disable selection
+    await tester.pumpWidget(buildFrame(true, null));
+    await tester.enterText(find.byType(TextField), 'abcdefghi');
+    await skipPastScrollingAnimation(tester);
+    expect(controller.selection.isCollapsed, true);
+
+    // Long press doesn't select anything
+    final Offset ePos = textOffsetToPosition(tester, 1);
+    final TestGesture gesture = await tester.startGesture(ePos, pointer: 7);
+    await tester.pump(const Duration(seconds: 2));
+    await gesture.up();
+    await tester.pump();
+    expect(controller.selection.isCollapsed, true);
+  });
+
+  testWidgets('An obscured TextField is selectable when enabled', (WidgetTester tester) async {
+    // This is a regression test for
+    // https://github.com/flutter/flutter/issues/24100
+
+    final TextEditingController controller = TextEditingController();
+    Widget buildFrame(bool obscureText, bool enableInteractiveSelection) {
+      return overlay(
+        child: TextField(
+          controller: controller,
+          obscureText: obscureText,
+          enableInteractiveSelection: enableInteractiveSelection,
+        ),
+      );
+    }
+
+    // Explicitly allow selection on obscured text
+    await tester.pumpWidget(buildFrame(true, true));
+    await tester.enterText(find.byType(TextField), 'abcdefghi');
+    await skipPastScrollingAnimation(tester);
+    expect(controller.selection.isCollapsed, true);
+
+    // Long press does select text
+    final Offset ePos2 = textOffsetToPosition(tester, 1);
+    final TestGesture gesture2 = await tester.startGesture(ePos2, pointer: 7);
+    await tester.pump(const Duration(seconds: 2));
+    await gesture2.up();
+    await tester.pump();
+    expect(controller.selection.isCollapsed, false);
+  });
+
   testWidgets('Multiline text will wrap up to maxLines', (WidgetTester tester) async {
     final Key textFieldKey = UniqueKey();