Added animated loading box.

rtv/content_generators.py

@@ -3,6 +3,7 @@ import praw
 
 from utils import clean, strip_subreddit_url, humanize_timestamp
 
+# TODO: rename, ... container?
 class BaseContent(object):
 
     @staticmethod

rtv/submission_viewer.py

@@ -3,7 +3,7 @@ import curses
 import sys
 
 from content_generators import SubmissionContent, SubredditContent
-from utils import curses_session
+from utils import curses_session, LoadScreen
 from viewer import BaseViewer
 
 class SubmissionViewer(BaseViewer):
@@ -50,7 +50,8 @@ class SubmissionViewer(BaseViewer):
     def refresh_content(self):
 
         self.add_loading()
-        self.content.reset()
+        with LoadScreen(self.stdscr):
+            self.content.reset()
         self.stdscr.clear()
         self.draw()
 
@@ -138,17 +139,3 @@ class SubmissionViewer(BaseViewer):
         win.addnstr(row, 1, text, n_cols)
 
         win.border()
-
-def main():
-
-    with curses_session() as stdscr:
-        r = praw.Reddit(user_agent='reddit terminal viewer (rtv) v0.0')
-        submission = SubredditContent(r).get(0)['object']
-        generator = SubmissionContent(submission)
-
-        viewer = SubmissionViewer(stdscr, generator)
-        viewer.loop()
-
-if __name__ == '__main__':
-
-    main()

rtv/subreddit_viewer.py

@@ -6,7 +6,7 @@ import sys
 from content_generators import SubredditContent, SubmissionContent
 from submission_viewer import SubmissionViewer
 from viewer import BaseViewer
-from utils import curses_session, text_input
+from utils import curses_session, text_input, LoadScreen
 
 class SubredditViewer(BaseViewer):
 
@@ -49,10 +49,10 @@ class SubredditViewer(BaseViewer):
 
     def refresh_content(self, subreddit=None):
 
-        self.add_loading()
         self.nav.page_index, self.nav.cursor_index = 0, 0
         self.nav.inverted = False
-        self.content.reset(subreddit=subreddit)
+        with LoadScreen(self.stdscr):
+            self.content.reset(subreddit=subreddit)
         self.stdscr.clear()
         self.draw()
 
@@ -73,10 +73,9 @@ class SubredditViewer(BaseViewer):
     def open_submission(self):
         "Select the current submission to view posts"
 
-        self.add_loading()
-
-        submission = self.content.get(self.nav.absolute_index)['object']
-        content = SubmissionContent(submission)
+        with LoadScreen(self.stdscr):
+            submission = self.content.get(self.nav.absolute_index)['object']
+            content = SubmissionContent(submission)
         viewer = SubmissionViewer(self.stdscr, content)
         viewer.loop()
 

rtv/utils.py

@@ -1,13 +1,76 @@
-from datetime import datetime, timedelta
-from contextlib import contextmanager
 import os
 import curses
+import time
+import threading
 from curses import textpad
+from datetime import datetime, timedelta
+from contextlib import contextmanager
 
 class EscapePressed(Exception):
     pass
 
 
+class LoadScreen(object):
+
+    def __init__(
+            self,
+            stdscr,
+            message='Downloading',
+            trail='...',
+            delay=0.5,
+            interval=0.4):
+
+        self._stdscr = stdscr
+        self.message = message
+        self.delay = delay
+        self.interval=interval
+        self.trail = trail
+
+        message_len = len(self.message) + len(self.trail)
+        n_rows, n_cols = stdscr.getmaxyx()
+        s_row = (n_rows - 2) / 2
+        s_col = (n_cols - message_len - 1) / 2
+        self.window = stdscr.derwin(3, message_len+2, s_row, s_col)
+
+        self._animator = threading.Thread(target=self.animate)
+        self._animator.daemon = True
+        self._is_running = None
+
+    def __enter__(self):
+
+        self._is_running = True
+        self._animator.start()
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+
+        self._is_running = False
+        self._animator.join()
+
+        del self.window
+        self._stdscr.refresh()
+
+    def animate(self):
+
+        # Delay before popping up the animation to avoid flashing
+        # the screen if the load time is effectively zero
+        start = time.time()
+        while (time.time() - start) < self.delay:
+            if not self._is_running:
+                return
+
+        while True:
+            for i in xrange(len(self.trail)+1):
+
+                if not self._is_running:
+                    return
+
+                self.window.erase()
+                self.window.border()
+                self.window.addstr(1, 1, self.message + self.trail[:i])
+                self.window.refresh()
+                time.sleep(self.interval)
+
+
 def clean(unicode_string):
     """
     Convert unicode string into ascii-safe characters.

rtv/viewer.py

@@ -83,7 +83,6 @@ class BaseViewer(object):
         self.nav = Navigator(self.content.get, **kwargs)
 
         self._subwindows = None
-        self.add_loading()
 
     def draw(self):
         raise NotImplementedError
@@ -107,20 +106,6 @@ class BaseViewer(object):
             continue
         self.stdscr.nodelay(0)
 
-    def add_loading(self):
-        "Draw a `loading` popup dialog in the center of the screen"
-
-        message = 'Loading...'
-
-        n_rows, n_cols = self.stdscr.getmaxyx()
-        win_rows, win_cols = 3, len(message)+2
-        start_row = (n_rows - win_rows) / 2
-        start_col = (n_cols - win_cols) / 2
-        window = self.stdscr.derwin(win_rows, win_cols, start_row, start_col)
-        window.border()
-        window.addstr(1, 1, message)
-        window.refresh()
-
     def draw_header(self):
 
         n_rows, n_cols = self._header_window.getmaxyx()