appium Activity used to start app doesn't exist or cannot be launched 问题解决
运行appium测试报错 “error: Failed to start an Appium session, err was: Error: Activity used to start app doesn’t exist or cannot ve launched! Make usre it exists and is launchable activity”
仔细检查了好几遍发现，activity是存在的，activity路径也是正确的
经过一番查找（当时就不淡定了，想到了开始却没想到这结尾，流下了没有技术的眼泪），问题解决如下：
注释掉setup中的如下两行：
desired_caps['appPackage'] = 'com.youdao.calculator.activities'
desired_caps['appActivity'] = 'com.youdao.calculator.activities.MainActivity'
再次运行，问题解决了。
说明：说明运行测试的时候我们不需要指定package和activity 这些信息，Appium会从apk中提取这些信息。
见：https://github.com/appium/appium/issues/2981 中paymand 的解释：
Don't know about the apk info tool above, but you can always get that info using the aapt tool from Android SDK with the following command:
adt/sdk/build-tools/android-4.4/aapt dump badging app.apk
Note: You shouldn't need to specify appPackage, appActivity, etc. since Appium should be able to extract those from the apk using the method above anyway.