code browser and fixes

examples/code_browser.py

@@ -0,0 +1,49 @@
+import sys
+
+from rich.syntax import Syntax
+from rich.traceback import Traceback
+from textual.app import App, ComposeResult
+from textual.layout import Container, Vertical
+from textual.reactive import Reactive
+from textual.widgets import DirectoryTree, Footer, Header, Static
+
+
+class CodeBrowser(App):
+
+    show_tree = Reactive.init(True)
+
+    def watch_show_tree(self, show_tree: bool) -> None:
+        self.set_class(show_tree, "-show-tree")
+
+    def on_load(self) -> None:
+        self.bind("t", "toggle_tree", description="Toggle Tree")
+        self.bind("q", "quit", description="Quit")
+
+    def compose(self) -> ComposeResult:
+        path = "./" if len(sys.argv) < 2 else sys.argv[1]
+        yield Header()
+        yield Container(
+            Vertical(DirectoryTree(path), id="tree-view"),
+            Vertical(Static(id="code"), id="code-view"),
+        )
+        yield Footer()
+
+    def on_directory_tree_file_click(self, event: DirectoryTree.FileClick) -> None:
+        code_view = self.query_one("#code", Static)
+        try:
+            syntax = Syntax.from_path(event.path, line_numbers=True, word_wrap=True)
+        except Exception:
+            code_view.update(Traceback())
+            self.sub_title = "ERROR"
+        else:
+            code_view.update(syntax)
+            self.query_one("#code-view").scroll_home(animate=False)
+            self.sub_title = event.path
+
+    def action_toggle_tree(self) -> None:
+        self.show_tree = not self.show_tree
+
+
+app = CodeBrowser(css_path="code_browser.css")
+if __name__ == "__main__":
+    app.run()