AppiumDriver升级到2.0.0版本引发的问题--Cannot instantiate the type AppiumDriver

1. 问题描述和起因

在使用Appium1.7.0及其以下版本的时候，我们可以直接使用如下代码来创建一个AppiumDriver实例进行对安卓设备的操作。

driver = new AndroidDriver(new URL("http://127.0.0.1:4723/wd/hub"), capabilities);

但在把Appium包升级到当前最新的2.0.0版本的时候，这段代码会引发如下的一问题

当前的pom.xml相关设置如下:记得把1.7.0改成2.0.0或者是将来更高级版本

<dependency>
  <groupId>io.appium</groupId>
  <artifactId>java-client</artifactId>
  <version>2.0.0</version>
  <del><version>1.7.0</version></del>
</dependency>

2.问题分析

究其原因，发现Appium2.0.0把AppiumDriver这个类改成了抽象函数，所以到导致了这个问题

public abstract class AppiumDriver extends RemoteWebDriver implements MobileDriver,
  ContextAware, Rotatable, FindsByAccessibilityId, LocationContext,
  DeviceActionShortcuts, TouchShortcuts, InteractsWithFiles,
  InteractsWithApps, ScrollsTo {

  private final static ErrorHandler errorHandler = new ErrorHandler(
      new ErrorCodesMobile(), true);
  private URL remoteAddress;
  private RemoteLocationContext locationContext;
  private ExecuteMethod executeMethod;

  // frequently used command parameters
  protected final String KEY_CODE = "keycode";
  protected final String PATH = "path";
  private final String SETTINGS = "settings";

根据2.0.0的Changelog的第一点：

AppiumDriver is now an abstract class, use IOSDriver and AndroidDriver which both extend it. You no longer need to include the PLATFORM_NAME desired capability since it's automatic for each class. Thanks to @TikhomirovSergey for all their work

AppiumDriver现在变成了一个抽象类，请使用从它继承下来的IOSDriver和AndroidDriver。你不再需要加上PLATFORM_NAME这个capability，因为代码会根据你使用的是IOSDriver或者AndroidDriver来确定究竟是哪个平台。

3.问题解决

根据问题分析，把代码修改如下，使用AndroidDriver而非原来的AppiumDriver。

public class NoetPadTest {
  /**
  * Create the test case
  *
  * @param testName name of the test case
  */
  private AndroidDriver driver;

  @Before
  public void setUp() throws Exception {
    // set up appium
    File classpathRoot = new File(System.getProperty("user.dir"));
    File appDir = new File(classpathRoot, "apps");
    File app = new File(appDir, "NotePad.apk");
    DesiredCapabilities capabilities = new DesiredCapabilities();
    capabilities.setCapability("deviceName","Android");
    //capabilities.setCapability("platformVersion", "4.2");
    capabilities.setCapability("platformName", "Android");
    //capabilities.setCapability("app", app.getAbsolutePath());
    capabilities.setCapability("appPackage", "com.example.android.notepad");
    capabilities.setCapability("appActivity", "com.example.android.notepad.NotesList");
    //capabilities.setCapability("appActivity", ".NotesList");
    driver = new AndroidDriver(new URL("http://127.0.0.1:4723/wd/hub"), capabilities);
  } 

  @After
  public void tearDown() throws Exception {
    driver.quit();
  }