Appium真机启动应用后脚本无法继续及uiautomator2签名报错求助

Hi there, let's work through these two frustrating Appium issues you're hitting on your real device. I'll break down each problem with likely causes and actionable fixes:

1. Script Halts After Application Launch #

It's super common for scripts to get stuck right after the app opens—usually this happens because Appium can't detect that the app is fully loaded, or there's a block like a permission popup in the way. Here's what to try:

• Verify your Desired Capabilities: Make sure appWaitPackage and appWaitActivity are set to match your app's actual package and main activity. For example:

  capabilities.setCapability("appWaitPackage", "com.your.app.package");
  capabilities.setCapability("appWaitActivity", "com.your.app.package.MainActivity");
  

  If your app has multiple splash screens or entry activities, you can use a wildcard like com.your.app.package.* to cover all possible launch activities.

• Add wait strategies: Increase implicit wait time to give the app enough time to load:

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

  Or use an explicit wait for a key UI element that appears once the app is ready:

  WebDriverWait wait = new WebDriverWait(driver, 30);
  wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("your_element_id")));
  

• Auto-grant permissions: Enable the autoGrantPermissions capability to let Appium automatically accept any permission popups on launch:

  capabilities.setCapability("autoGrantPermissions", true);
  

• Check device settings: Double-check that USB debugging is enabled on your device, and you've allowed the computer to connect to the device (you might see a popup on the device the first time you connect). Also ensure "Install unknown apps" is enabled for your computer's connection.

2. 'Cannot use apksigner tool for signing.' Error with UIAutomator2 #

That exit code 20 error with apksigner typically points to a compatibility issue between the build tools version you're using and the UIAutomator2 server APK, or a problem with the signing keys. Here's how to fix it:

• Update Android Build Tools: The 28.0.3 build tools version you're using might be outdated and incompatible with the newer UIAutomator2 server. Open Android Studio's SDK Manager, go to the "SDK Tools" tab, and install a newer stable version (like 30.0.3 or 33.0.2). Then make sure Appium is using this updated version—you can confirm the path in your Appium logs or set the ANDROID_HOME environment variable to point to your SDK root.

• Re-sign the UIAutomator2 server APK manually: Sometimes the pre-signed APK from Appium has issues. Grab the testkey files from your Appium installation path and re-sign the server APK with your updated apksigner tool:

  /Users/tapan.khimani/Library/Android/sdk/build-tools/[NEW_VERSION]/apksigner sign --key /Applications/Appium.app/Contents/Resources/app/node_modules/appium/node_modules/appium-adb/keys/testkey.pk8 --cert /Applications/Appium.app/Contents/Resources/app/node_modules/appium/node_modules/appium-adb/keys/testkey.x509.pem /Applications/Appium.app/Contents/Resources/app/node_modules/appium/node_modules/appium-uiautomator2-server/apks/appium-uiautomator2-server-v4.3.0.apk
  

  Replace [NEW_VERSION] with the updated build tools version you installed.

• Reinstall the UIAutomator2 server module: Corrupted module files can cause this issue. If you're using a local Appium installation, uninstall and reinstall the module via npm:

  npm uninstall appium-uiautomator2-server
  npm install appium-uiautomator2-server
  

  If you're using the Appium desktop app, try reinstalling the app itself to get fresh copies of all dependencies.

• Check file permissions: Ensure the testkey.pk8 and testkey.x509.pem files have read permissions. Fix this with:

  chmod 644 /Applications/Appium.app/Contents/Resources/app/node_modules/appium/node_modules/appium-adb/keys/testkey.pk8
  chmod 644 /Applications/Appium.app/Contents/Resources/app/node_modules/appium/node_modules/appium-adb/keys/testkey.x509.pem
  

内容的提问来源于stack exchange，提问作者Tapan Khimani