问题一
Could not locate a Flask application. You did not provide the "FLASK_APP" environment variable, and a "wsgi.py" or "app.py" module was not found in the current directory.
解决
将app.py放在当前根目录下，输入pwd就可以知道当前根目录
问题二
NoAppException: Could not locate a Flask application. You did not provide the "FLASK_APP" environment variable, and a "wsgi.py" or "app.py" module was not found in the current directory.
解决
在之前的目录下有 .env 或 .flaskenv 文件，删除即可
问题三
socket.error: [Errno 48] Address already in use
解决
用$ sudo lsof -i:5000 查看进程，然后杀死进程sudo kill #pid。
问题四
出现了CSS文件没有渲染的问题
解决
from datetime import timedelta
# 设置静态文件缓存过期时间
app.config['SEND_FILE_MAX_AGE_DEFAULT'] = timedelta(seconds=1)
# 也可以这样写：
app.send_file_max_age_default = timedelta(seconds=1)
rel 要写icon。不能自己编！！！
问题五
SyntaxError: Non-ASCII character '\xe7' in file /Users/Huizhi/watchlist/app.py on line 50, but no encoding declared;
解决
在文件app.py前面加# -- coding: utf-8 -
问题六
global name 'redirect' is not defined
解决
from flask import redirect
