Square Web API for Android适配问题：连接Square Reader时应用崩溃重启

Let’s work through the most likely issues causing your app to crash or restart when trying to connect to Square Reader, and fix them step by step:

• Validate your Intent format thoroughly
  Even a tiny typo in that intent:#Intent;action=com.square... link can break the whole flow and trigger a crash. Right before launching the intent, print the full string to logcat—look for missing semicolons, misspelled action names, or malformed parameters like S.com.squareup.pos.WEB_CALLBACK_URI. Double-check that every required field (like package=com.squareup.pos) is included and correctly formatted.

• Fix your AndroidManifest callback setup
  If your app isn’t configured to receive the callback from Square Reader, the flow can fail silently or crash. Make sure you have an Activity with an intent filter that matches your callback URI:

  <activity android:name=".YourCallbackHandlingActivity">
      <intent-filter>
          <action android:name="android.intent.action.VIEW" />
          <category android:name="android.intent.category.DEFAULT" />
          <category android:name="android.intent.category.BROWSABLE" />
          <!-- Replace with your app's actual callback scheme/host -->
          <data android:scheme="your-app-custom-scheme" android:host="reader-callback" />
      </intent-filter>
  </activity>
  

  Also, don’t forget to declare the INTERNET permission in your manifest—it’s required for any communication with Square’s API.

• Ditch 127.0.0.1 for your dev server
  Square Reader is a separate app on your device, so it can’t reach 127.0.0.1 (that points to its own local loopback, not your dev machine). Swap the IP with your computer’s local LAN address (like 192.168.1.105) so the Reader app can send callbacks back to your server.

• Check Square Reader app and device compatibility
  Make sure the Square Reader app on your test device is fully updated—old versions often have bugs that cause crashes when handling intents. Also, confirm your device meets Square’s minimum requirements (Android 7.0+ for most features) and that hardware like NFC (for contactless payments) is enabled if you’re using that functionality.

• Catch unhandled exceptions
  Your app might be crashing because it’s not handling errors from the intent launch or callback. Wrap the intent-launching code in try-catch blocks and log exceptions to logcat. Also, override onNewIntent() in your callback Activity, add logging there, and make sure you’re parsing the incoming intent correctly—this will help you confirm if the callback is ever being received.

• Verify Square Developer Dashboard settings
  Ensure the callback URIs you’re using (both S.browser_fallback_url and S.com.squareup.pos.WEB_CALLBACK_URI) are added to the allowed list in your Square Developer Dashboard under your app’s settings. Square blocks unapproved URIs, which can lead to silent failures or unexpected crashes.

内容的提问来源于stack exchange，提问作者Jake Graff