Build a wallet tutorial: draft steps 1-3

1. wxPython app that shows XRPL data (once)
2. threaded app monitoring XRPL in background
3. Decode address & watch for balance

content/_code-samples/build-a-wallet/py/1_hello.py

@@ -0,0 +1,46 @@
+# "Build a Wallet" tutorial, step 1: slightly more than "Hello World"
+
+import xrpl
+import wx
+
+class TWaXLFrame(wx.Frame):
+    """
+    Tutorial Wallet for the XRP Ledger (TWaXL)
+    user interface, main frame.
+    """
+    def __init__(self, url):
+        super(TWaXLFrame, self).__init__(None, title="TWaXL")
+
+        self.client = xrpl.clients.JsonRpcClient(url)
+
+        main_panel = wx.Panel(self)
+        main_sizer = wx.BoxSizer(wx.VERTICAL)
+        main_panel.SetSizer(main_sizer)
+
+        st = wx.StaticText(main_panel, label=self.get_validated_ledger())
+        main_sizer.Add(st, wx.SizerFlags().Border(wx.TOP|wx.LEFT, 25))
+
+    def get_validated_ledger(self):
+        try:
+            response = self.client.request(xrpl.models.requests.Ledger(
+                ledger_index="validated"
+            ))
+        except Exception as e:
+            return f"Failed to get validated ledger from server. ({e})"
+
+        if response.is_successful():
+            return f"Latest validated ledger: {response.result['ledger_index']}"
+        else:
+            # Connected to the server, but the request failed. This can
+            # happen if, for example, the server isn't synced to the network
+            # so it doesn't have the latest validated ledger.
+            return f"Server returned an error: {response.result['error_message']}"
+
+if __name__ == "__main__":
+    JSON_RPC_URL = "https://s.altnet.rippletest.net:51234/"
+    #JSON_RPC_URL = "http://localhost:5005/"
+
+    app = wx.App()
+    frame = TWaXLFrame(JSON_RPC_URL)
+    frame.Show()
+    app.MainLoop()