Alternative to the deprecated FileObserver constructor for API level <29

Question

According to the documentation, both FileObserver(path: String!) and FileObserver(path: String!, mask: Int) are deprecated (I don't know when). However, all other constructors were only added in API 29 (10/Q) and I'm trying to support from API 19 (4/KitKat) onwards.

What will be the alternative to monitor a file once these two constructors get removed in later APIs?

Answer 1

To answer this directly,

1. The new api requires a File type as the first parameter instead of a string. IE FileObserver(File(path), mask)

2. If you need to support APIs before and after deprecation, consider writing a wrapper function. Example (in kotlin)

open class FileObserverApiWrapper(path: String, mask: Int) {
  private var fileObserver: FileObserver? = null

  init {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
      fileObserver = object : FileObserver(File(path), mask) {
        override fun onEvent(event: Int, path: String?) {
          [email protected](event,path)
        }
      }
    } else {
      @Suppress("DEPRECATION")
      fileObserver = object : FileObserver(path, mask) {
        override fun onEvent(event: Int, path: String?) {
          [email protected](event,path)
        }
      }
    }
  }

  /**
   * @description does nothing, can be overridden. Equivalent to FileObserver.onEvent
   */
  open fun onEvent(event: Int, path: String?){}

  open fun startWatching() {
    fileObserver?.startWatching()
  }

  open fun stopWatching() {
    fileObserver?.stopWatching()
  }
}