Hey there, let’s work through this DJI remote controller/drone recognition problem step by step— I’ve tackled similar snags with older Android devices and Mavic Pro setups before, so let’s narrow down the causes.

1. First Verify Basic Hardware & Official App Connectivity #

Start with the simplest checks to rule out non-code issues:

• Physical Connection Check: Did you use a working OTG cable to connect your Redmi 4A to the Mavic Pro remote’s USB port? Redmi 4A requires manually enabling OTG in Settings > More Connection Methods— double-check this toggle is on.
• Official App Validation: Install DJI Go 4 on your phone and test if it can recognize the remote/drone. If the official app fails, the problem is with hardware pairing, battery levels, or remote firmware (update via DJI Assistant 2 if needed). If the official app works, we know the issue is specific to your demo project.

2. Fix Android 6.0.1 (Marshmallow) Permission Limitations #

Android 6+ introduced runtime permissions, which the DJI SDK relies on heavily:

• Dynamic Permissions: The default demo might not handle runtime permissions properly for Marshmallow. Ensure your app requests critical permissions like ACCESS_FINE_LOCATION, WRITE_EXTERNAL_STORAGE, and INTERNET at launch. Add a permission request flow in your main activity if you don’t see a permission popup when opening the app.
• MIUI System Restrictions: Redmi’s MIUI has extra security controls. Go to your app’s settings in MIUI and enable:
  • Autostart permission (so the DJI SDK can run in the background)
  • Background pop-up permissions (for SDK status alerts)
  • All file access permissions

3. Validate DJI SDK & API Key Configuration #

Even a tiny misconfiguration here can block device recognition:

• API Key Accuracy: Double-check your API key in AndroidManifest.xml under the <meta-data> tag for com.dji.sdk.API_KEY. Ensure:
  • The key matches exactly what’s in your DJI Developer Account
  • Your app’s package name (default com.dji.gsdemo for this demo) is registered with the key in the DJI backend
  • The correct SHA-1 fingerprint for your debug/release build is added to the DJI backend (generate this via Android Studio’s Gradle > App > Tasks > Android > signingReport)
• SDK Version Compatibility: The demo uses an older DJI SDK— confirm it supports the Mavic Pro. If you’re on SDK 4.x, it should work, but ensure there are no dependency conflicts in your build.gradle file.

4. Adapt to Android Studio 3.0.1 & Environment Settings #

• Java 8 Support: DJI SDK requires Java 8 compatibility. Add this to your app-level build.gradle if it’s missing:

  compileOptions {
      sourceCompatibility JavaVersion.VERSION_1_8
      targetCompatibility JavaVersion.VERSION_1_8
  }
  

• Simulator Checks (If Using):
  • Ensure DJI Assistant 2 is running, the Mavic Pro simulator is configured, and your phone is on the same network as the simulator
  • Confirm the remote controller is connected to your phone via USB/OTG when using the simulator

5. Use Logcat to Pinpoint Exact Errors #

Filter Logcat for DJI or dji tags to see detailed error messages:

• API key invalid: Points to a misconfigured key/package name/SHA-1
• Permission denied: Means runtime permissions aren’t granted
• Device connection timeout: Indicates a hardware/OTG issue or SDK initialization failure

内容的提问来源于stack exchange，提问作者Codir