Advanced django admin integration

localized_fields/widgets.py

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+from typing import List
+
+from django.conf import settings
+from django import forms
+from django.contrib.admin import widgets
+from django.template.loader import render_to_string
+
+from .localized_value import LocalizedValue
+
+
+class LocalizedFieldWidget(forms.MultiWidget):
+    """Widget that has an input box for every language."""
+    widget = forms.Textarea
+
+    def __init__(self, *args, **kwargs):
+        """Initializes a new instance of :see:LocalizedFieldWidget."""
+
+        widgets = []
+
+        for _ in settings.LANGUAGES:
+            widgets.append(self.widget)
+
+        super(LocalizedFieldWidget, self).__init__(widgets, *args, **kwargs)
+
+    def decompress(self, value: LocalizedValue) -> List[str]:
+        """Decompresses the specified value so
+        it can be spread over the internal widgets.
+
+        Arguments:
+            value:
+                The :see:LocalizedValue to display in this
+                widget.
+
+        Returns:
+            All values to display in the inner widgets.
+        """
+
+        result = []
+
+        for lang_code, _ in settings.LANGUAGES:
+            if value:
+                result.append(value.get(lang_code))
+            else:
+                result.append(None)
+
+        return result
+
+
+class AdminLocalizedFieldWidget(LocalizedFieldWidget):
+    widget = widgets.AdminTextareaWidget
+    template = 'localized_fields/admin/widget.html'
+
+    def render(self, name, value, attrs=None):
+        if self.is_localized:
+            for widget in self.widgets:
+                widget.is_localized = self.is_localized
+        # value is a list of values, each corresponding to a widget
+        # in self.widgets.
+        if not isinstance(value, list):
+            value = self.decompress(value)
+        output = []
+        final_attrs = self.build_attrs(attrs)
+        id_ = final_attrs.get('id')
+        for i, widget in enumerate(self.widgets):
+            try:
+                widget_value = value[i]
+            except IndexError:
+                widget_value = None
+            if id_:
+                final_attrs = dict(final_attrs, id='%s_%s' % (id_, i))
+            widget_attrs = self.build_widget_attrs(widget, widget_value, final_attrs)
+            output.append(widget.render(name + '_%s' % i, widget_value, widget_attrs))
+        context = {
+            'id': final_attrs.get('id'),
+            'name': name,
+            'widgets': zip([code for code, lang in settings.LANGUAGES], output),
+            'available_languages': settings.LANGUAGES
+        }
+        return render_to_string(self.template, context)
+
+    def build_widget_attrs(self, widget, value, attrs):
+        attrs = dict(attrs)  # Copy attrs to avoid modifying the argument.
+        if (not widget.use_required_attribute(value) or not widget.is_required) \
+                and 'required' in attrs:
+            del attrs['required']
+        return attrs