學過selenium的都知道，一般等待元素載入有三種辦法:

• （1）sleep                  強制等待。示例：Thread.sleep（60000）
• （2）implicitlyWait   隱式等待。全域性等待30s不管元素是否已經載入

  示例：driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);

• （3）WebDriverWait     顯示等待，這個需要增加一定等待時間，顯示等待時間可以通過WebDriverWait 和util來決定,比如這個timeOut是60，如果該元素60s以內出現就不在等待

WebDriverWait wait = new
 
 WebDriverWait(driver, 60);
    WebElement e= wait.until(new  ExpectedCondition<WebElement>() {
            @Override
            public WebElement apply(WebDriver d){
                return d.findElement(By.id("q"));
            }
        })

  以上三種方法中，只用WebDriverWait是selenium所特有，在java-client中也找不到相應的，如果想使用這種方法怎麼辦？

改造輪子，首先新增AndroidDriverWait.java, 其實是將WebDriverWait的型別改成AndroidDriverWait

具體程式碼如下：

 import org.openqa.selenium.NotFoundException;
 import org.openqa.selenium.TimeoutException;
 import org.openqa.selenium.WebDriver;
 import org.openqa.selenium.WebDriverException;
 import org.openqa.selenium.remote.RemoteWebDriver;
 import
 
 org.openqa.selenium.support.ui.Clock;
 import org.openqa.selenium.support.ui.FluentWait;
 import org.openqa.selenium.support.ui.Sleeper;
 import org.openqa.selenium.support.ui.SystemClock;
 
 import io.appium.java_client.android.AndroidDriver;
 
 import java.util.concurrent.TimeUnit;
 
 /**
  * A specialization of {@link FluentWait} that uses WebDriver instances.
  */
 public classAndroidDriverWaitextendsFluentWait<AndroidDriver> {
   public final static long DEFAULT_SLEEP_TIMEOUT = 500;
   private final WebDriver driver;
 
   /**
    * Wait will ignore instances of NotFoundException that are encountered (thrown) by default in
    * the 'until' condition, and immediately propagate all others.  You can add more to the ignore
    * list by calling ignoring(exceptions to add).
    *
    * @param driver The WebDriver instance to pass to the expected conditions
    * @param timeOutInSeconds The timeout in seconds when an expectation is called
    * @see AndroidDriverWait#ignoring(java.lang.Class)
    */
   publicAndroidDriverWait(AndroidDriver driver, long timeOutInSeconds){
     this(driver, new SystemClock(), Sleeper.SYSTEM_SLEEPER, timeOutInSeconds, DEFAULT_SLEEP_TIMEOUT);
   }
 
   /**
    * Wait will ignore instances of NotFoundException that are encountered (thrown) by default in
    * the 'until' condition, and immediately propagate all others.  You can add more to the ignore
    * list by calling ignoring(exceptions to add).
    *
    * @param driver The WebDriver instance to pass to the expected conditions
    * @param timeOutInSeconds The timeout in seconds when an expectation is called
    * @param sleepInMillis The duration in milliseconds to sleep between polls.
    * @see AndroidDriverWait#ignoring(java.lang.Class)
    */
   publicAndroidDriverWait(AndroidDriver driver, long timeOutInSeconds, long sleepInMillis){
     this(driver, new SystemClock(), Sleeper.SYSTEM_SLEEPER, timeOutInSeconds, sleepInMillis);
   }
 
   /**
    * @param driver The WebDriver instance to pass to the expected conditions
    * @param clock The clock to use when measuring the timeout
    * @param sleeper Object used to make the current thread go to sleep.
    * @param timeOutInSeconds The timeout in seconds when an expectation is
    * @param sleepTimeOut The timeout used whilst sleeping. Defaults to 500ms called.
    */
   publicAndroidDriverWait(AndroidDriver driver, Clock clock, Sleeper sleeper, long timeOutInSeconds,
       long sleepTimeOut){
     super(driver, clock, sleeper);
     withTimeout(timeOutInSeconds, TimeUnit.SECONDS);
     pollingEvery(sleepTimeOut, TimeUnit.MILLISECONDS);
     ignoring(NotFoundException.class);
     this.driver = driver;
   }
 
   @Override
   protected RuntimeException timeoutException(String message, Throwable lastException){
     TimeoutException ex = new TimeoutException(message, lastException);
     ex.addInfo(WebDriverException.DRIVER_INFO, driver.getClass().getName());
     if (driver instanceof RemoteWebDriver) {
       RemoteWebDriver remote = (RemoteWebDriver) driver;
       if (remote.getSessionId() != null) {
         ex.addInfo(WebDriverException.SESSION_ID, remote.getSessionId().toString());
       }
       if (remote.getCapabilities() != null) {
         ex.addInfo("Capabilities", remote.getCapabilities().toString());
       }
     }
     throw ex;
   }
 }

接著需要修改介面：ExpectedCondition，將其WebDriver的型別替換為AndroidDriver

具體程式碼：

public interface ExpectedCondition<T> extends Function<AndroidDriver, T> {}

經過修改之後，就可以在appium中直接使用：

        //wait for 60s if WebElemnt show up less than 60s , then return , until 60s
        WebElement showClose = new AndroidDriverWait(driver, 60)
                .until(new ExpectedCondition<WebElement>() {
                    public WebElement apply(AndroidDriver d) {
                        return d.findElement(By
                                .id("com.zhihu.android:id/showcase_close"));
                    }

                });