gui: add restricted input

arcade/examples/gui/exp_restricted_input.py

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+"""Example of using experimental UIRestrictedInputText.
+
+If Arcade and Python are properly installed, you can run this example with:
+python -m arcade.examples.gui.exp_restricted_input
+"""
+
+from __future__ import annotations
+
+import arcade
+from arcade.gui import UIAnchorLayout, UIBoxLayout, UIView
+from arcade.gui.experimental.restricted_input import UIIntInput
+
+
+class MyView(UIView):
+    def __init__(self):
+        super().__init__()
+        self.background_color = arcade.uicolor.BLUE_BELIZE_HOLE
+
+        root = self.ui.add(UIAnchorLayout())
+        bars = root.add(UIBoxLayout(space_between=10))
+
+        # UIWidget based progress bar
+        self.input_field = UIIntInput(width=300, height=40, font_size=22)
+        bars.add(self.input_field)
+
+
+def main():
+    window = arcade.Window(antialiasing=False)
+    window.show_view(MyView())
+    arcade.run()
+
+
+if __name__ == "__main__":
+    main()

arcade/gui/experimental/restricted_input.py

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+"""
+This is an experimental implementation of a restricted input field.
+If the implementation is successful, the feature will be merged into the existing UIInputText class.
+"""
+
+from typing import Optional
+
+from arcade.gui import UIEvent, UIInputText
+
+
+class UIRestrictedInput(UIInputText):
+    """
+    A text input field that restricts the input to a certain type.
+
+    This class is meant to be subclassed to create custom input fields
+     that restrict the input by providing a custom validation method.
+
+     Invalid inputs are dropped.
+    """
+
+    @property
+    def text(self):
+        """Text of the input field."""
+        return self.doc.text
+
+    @text.setter
+    def text(self, text: str):
+        if not self.validate(text):
+            # if the text is invalid, do not update the text
+            return
+
+        # we can not call super().text = text here: https://bugs.python.org/issue14965
+        UIInputText.text.__set__(self, text)  # type: ignore
+
+    def on_event(self, event: UIEvent) -> Optional[bool]:
+        # check if text changed during event handling,
+        # if so we need to validate the new text
+        old_text = self.text
+        pos = self.caret.position
+
+        result = super().on_event(event)
+        if not self.validate(self.text):
+            self.text = old_text
+            self.caret.position = pos
+
+        return result
+
+    def validate(self, text) -> bool:
+        """Override this method to add custom validation logic.
+
+        Be aware that an empty string should always be valid.
+        """
+        return True
+
+
+class UIIntInput(UIRestrictedInput):
+    def validate(self, text) -> bool:
+        if text == "":
+            return True
+
+        try:
+            int(text)
+            return True
+        except ValueError:
+            return False
+
+
+class UIFloatInput(UIRestrictedInput):
+    def validate(self, text) -> bool:
+        if text == "":
+            return True
+
+        try:
+            float(text)
+            return True
+        except ValueError:
+            return False
+
+
+class UIRegexInput(UIRestrictedInput):
+    def __init__(self, *args, pattern: str = r".*", **kwargs):
+        super().__init__()
+        self.pattern = pattern
+
+    def validate(self, text: str) -> bool:
+        if text == "":
+            return True
+
+        import re
+
+        return re.match(self.pattern, text) is not None

tests/unit/gui/test_exp_restricted_input.py

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+from arcade.gui.experimental import UIPasswordInput
+from arcade.gui.experimental.restricted_input import UIRestrictedInput, UIIntInput, UIRegexInput
+
+
+def test_restricted_input_ignore_invalid_input(ui):
+    class FailingInput(UIRestrictedInput):
+        def validate(self, text) -> bool:
+            return text == ""
+
+    fi = ui.add(FailingInput())
+
+    # WHEN
+    ui.click(fi.center_x, fi.center_y)
+    for l in "abcdef-.,1234567890":
+        ui.type_text(l)
+
+    assert fi.text == ""
+
+
+def test_int_input_accepts_only_digits(ui):
+    fi = ui.add(UIIntInput())
+
+    # WHEN
+    ui.click(fi.center_x, fi.center_y)
+    for l in "abcdef-.,1234567890":
+        ui.type_text(l)
+
+    assert fi.text == "1234567890"
+
+
+def test_float_input_accepts_only_float(ui):
+    fi = ui.add(UIIntInput())
+
+    # WHEN
+    ui.click(fi.center_x, fi.center_y)
+    for l in "abcdef-.,1234567890":
+        ui.type_text(l)
+
+    assert fi.text == "1234567890"
+
+
+def test_regex_input_accepts_only_matching_patterns(ui):
+    fi = ui.add(UIRegexInput(pattern="^[0-9]+$"))
+
+    # WHEN
+    ui.click(fi.center_x, fi.center_y)
+    for l in "abcdef-.,1234567890":
+        ui.type_text(l)
+
+    assert fi.text == "1234567890"
+