appium 调试问题--UiAutomator died while responding to command

运行程序问题：

解决办法：

　　手机系统版本较低导致，我是V4.2.2,在android 4.3 系统上运行正常

代码如下：

#coding=utf-8
'''
作者：xxx
功能：测试计算器基本功能

注意事项：需要android 4.3以上系统
'''
from appium import webdriver
import time

#PATH = lambda p: os.path.abspath(os.path.join(os.path.dirname(__file__), p))
desired_caps={}
desired_caps['platformName']='Android'
desired_caps['platformVersion']='4.3'
desired_caps['deviceName']='4d005eebb070606f'
#desired_caps['deviceName']='MBIB8LOJL7MJ7L7H'
desired_caps['appPackage'] = 'com.youba.calculate'
desired_caps['appActivity'] = '.MainActivity' #原生的需要加.
desired_caps['browserName'] = ''

driver = webdriver.Remote('http://localhost:4723/wd/hub', desired_caps)

print "成功打开app！"

time.sleep(1)

driver.find_element_by_id("com.youba.calculate:id/btn_ac").click()
driver.find_element_by_name("").click()
driver.find_element_by_name("×").click()
driver.find_element_by_name("").click()
driver.find_element_by_name("=").click()

text=driver.find_element_by_id("com.youba.calculate:id/et_echo").text

if text==5*2:
    print "测试通过"

driver.quit()