Appium驱动程序在应用程序的UI中找不到任何元素。尝试通过id、xpath和Name查找元素，但似乎没有任何效果

Question

package com.example;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Set;
import java.util.concurrent.TimeUnit;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.remote.DesiredCapabilities;
import org.openqa.selenium.remote.SessionId;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Test;
import io.appium.java_client.AppiumDriver;
import io.appium.java_client.MobileBy;
import io.appium.java_client.android.AndroidDriver;
import io.appium.java_client.android.AndroidElement;
import io.appium.java_client.remote.AndroidMobileCapabilityType;
import io.appium.java_client.remote.MobileCapabilityType;

public class FirstAppiumTest {
    //protected AndroidDriver<AndroidElement> driver = null;
    public AppiumDriver driver;
    @BeforeTest
    public void Setup() throws MalformedURLException
    {String url = "http://127.0.0.1:4723/wd/hub";

        DesiredCapabilities cap=new DesiredCapabilities();

    cap.setCapability("noReset","true");
    cap.setCapability("deviceName","Redmi 4");
    cap.setCapability("platformVersion","7.1.2");
    cap.setCapability("platformName","Android");
    cap.setCapability("app","C:\\Appium\\selendroid-test-app.apk");



     driver=new AndroidDriver(new URL(url),cap);
    }
    @Test
    public void Simpletest() throws InterruptedException
    {  
        driver.manage().timeouts().implicitlyWait(50,TimeUnit.SECONDS);
        //driver.findElement(By.className("android.widget.Button")).click();
        WebElement e1=driver.findElement(By.id("showToastButton"));
        e1.click();
         System.out.print(e1);
 String text=driver.findElement(By.className("android.widget.EditText")).getText();
     System.out.print(text);
     String src = driver.getPageSource();
       System.out.println(src);         
      driver.quit();


    }
}