布局XML资源存在但编译器报‘not found’及声音合成器崩溃问题求助

Hey Jim, let's break down your two issues with practical fixes and debugging steps:

This is a tricky but super common problem—here’s what to check systematically:

• Double-check resource naming & syntax: Android is case-sensitive! Make sure your resource name (e.g., @drawable/my_icon) matches the actual file name exactly (no uppercase letters where there shouldn’t be, no typos). Also confirm you’re using the right resource type prefix (@drawable/, @string/, @color/—mixing these up is easy!).
• Verify resource directory structure: Ensure your resource is in the correct folder (e.g., a vector drawable might be in drawable-v24 but your layout is referencing it without version qualifiers, causing older SDKs to miss it). Also check if the resource was accidentally placed in a debug or release-only folder when it should be in the main resources.
• Clean build & invalidate caches: Gradle can sometimes cache old resource references. Run ./gradlew clean from the terminal, then go to Android Studio’s File > Invalidate Caches... > Invalidate and Restart to clear stale data.
• Check for conflicting resources: If you’re using third-party libraries, there might be a resource name collision. Try renaming your local resource to something unique and update the layout reference.
• Fix incorrect R class imports: Accidentally importing android.R instead of your app’s package-specific R class will cause this error. Double-check your layout’s associated activity/fragment imports.

The AudioFlinger/AudioTrack error with code -20 gives us a strong clue—here’s how to debug this:

• First, understand error code -20: On Android 5.0 and 7.0, this typically points to resource exhaustion or an invalid operation with AudioTrack. The 8-run pattern suggests you’re not properly releasing audio resources after each use.
• Audit AudioTrack lifecycle: Every time you create an AudioTrack instance, you must call release() when you’re done with it. If you skip this, each run will leak a bit of audio system memory, and by the 8th run, the device hits its resource limit (simulators usually have looser resource constraints than physical phones, which is why it works there).
• Capture full crash logs: The partial error info isn’t enough to pinpoint the exact issue. Connect your phone to your computer, run adb logcat *:E in the terminal, and reproduce the crash. This will give you the full stack trace—look for lines that show where the AudioTrack operation is failing (e.g., initialize() or play()).
• Check thread safety: AudioTrack operations shouldn’t run on the main thread. Make sure you’re handling audio playback in a dedicated background thread or using HandlerThread for audio tasks—blocking the main thread can cause unexpected state issues in the audio system.
• Regarding API level changes: Android Studio absolutely supports setting compileSdkVersion and targetSdkVersion to 21—you might have been looking in the wrong place. Check your app-level build.gradle file (not the project-level one) and update those values manually if the UI dropdown isn’t showing it. That said, the crash is unlikely to be caused by the API level itself—focus on resource cleanup first.

内容的提问来源于stack exchange，提问作者Jim Tan