Appium hybrid app could not identify the locators

I am trying to enter a mobile number for our app. Still got error
This is the screenshot .This is a hybrid mobile app. I took xpath,className…

MobileElement element= (MobileElement)driver.findElement(By.className("text_field"));

element.sendKeys("944556453");
MobileElement element1= (MobileElement) driver.findElement(By.xpath("//*[@id=\'main\']/div[2]/div[1]"));
element1.click();

still got same error:

org.openqa.selenium.NoSuchElementException: An element could not be located on the page using the given search parameters. (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 668 milliseconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html
Build info: version: '3.0.1', revision: '1969d75', time: '2016-10-18 09:49:13 -0700'
System info: host: 'naveen-Inspiron-3542', ip: '127.0.1.1', os.name: 'Linux', os.arch: 'amd64', os.version: '4.4.0-66-generic', java.version: '1.8.0_121'
Driver info: io.appium.java_client.android.AndroidDriver
Capabilities [{app=/home/naveen/IdeaProjects/QberLoginPage/app/Qber_Customer_V1.6.0.apk, appPackage=com.ionicframework.qber653346, networkConnectionEnabled=true, warnings={}, databaseEnabled=false, deviceName=192.168.1.3:5555, platform=LINUX, deviceUDID=192.168.1.3:5555, appActivity=MainActivity, desired={app=/home/naveen/IdeaProjects/QberLoginPage/app/Qber_Customer_V1.6.0.apk, appPackage=com.ionicframework.qber653346, appActivity=MainActivity, appium-version=1.6.3, platformVersion=4.4.4, platformName=Android, deviceName=Huawei}, appium-version=1.6.3, platformVersion=4.4.4, webStorageEnabled=false, locationContextEnabled=false, takesScreenshot=true, javascriptEnabled=true, platformName=Android}]
Session ID: 0579fefb-16b9-4bdb-aa41-8f723927e99c
*** Element info: {Using=class name, value=text_field}

What should I do ?

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