appium+python 滑动屏幕直至某元素出现

获取屏幕宽高：
width = driver.get_window_size()['width']
height = driver.get_window_size()['height']

while循环10次
i=0
while i < 10:
    try:
        driver.find_element_by_xpath("path").click()#尝试点击元素
 break
    except Exception as e:
        driver.swipe(width/2,height*0.8,width/2,height*0.2)#滑动屏幕
        i=i+1