使主线程等待协程 kotlin

Question

I am trying to compress an image in android but and I don't want to use runBlocking . How can I make the main UI thread to wait for the compression to take place? Currently, I am doing this

var compressedImage: File? = null
runBlocking {
    compressedImage = Compressor.compress(this@UpdateProfileActivity, cachedFile.absoluteFile)
}
camera = "gallery"
//doing something with the compressedImage.

How to do it without runBlocking ?

Answer 1

You should not make the main-thread to wait for task completion. It causes freezing of your app until the main-thread gets free. You can do your long-running job in another thread, then switch to the main-thread to do whatever you want.

var compressedImage: File? = null
CoroutineScope().launch(Dispatchers.IO) {
    compressedImage = Compressor.compress(this@UpdateProfileActivity, cachedFile.absoluteFile)
    
    withContext(Dispatchers.Main) {
        camera = "gallery"
        // doing something with the compressedImage.
    }
}