How to solve Handler() deprecated?

问题

Could anyone know, how to fix deprecated waring or any alternate solution for this.

 Handler().postDelayed({
        context?.let {
           //code
        }
    }, 3000)

回答1:

If you want to avoid the null check thing in Kotlin (? or !!) you can use Looper.getMainLooper() if your Handler is working with some UI related thing, like this:

Handler(Looper.getMainLooper()).postDelayed({
   Toast.makeText(this@MainActivity, "LOOPER", Toast.LENGTH_SHORT).show()
}, 3000)

回答2:

Consider using coroutines

scope.launch {
    delay(3000L)
    // do stuff
}

回答3:

The deprecated function is that constructor for Handler. Use Handler(Looper.myLooper()) .postDelayed(runnable, delay) instead

回答4:

Use Executor instead of handler for more info Executor

to achieve post delay use ScheduledExecutorService

    private static final ScheduledExecutorService worker = Executors.newSingleThreadScheduledExecutor();
        Runnable runnable = new Runnable() {
  public void run() {
      // Do something
  }
  };
worker.schedule(runnable, 2, TimeUnit.SECONDS);

回答5:

According to the document (https://developer.android.com/reference/android/os/Handler), "Implicitly choosing a Looper during Handler construction can lead to bugs where operations are silently lost (if the Handler is not expecting new tasks and quits), crashes (if a handler is sometimes created on a thread without a Looper active), or race conditions, where the thread a handler is associated with is not what the author anticipated. Instead, use an Executor or specify the Looper explicitly, using Looper#getMainLooper, {link android.view.View#getHandler}, or similar. If the implicit thread local behavior is required for compatibility, use new Handler(Looper.myLooper()) to make it clear to readers."

we should quit using the constructor without a Looper, specific a Looper instead.

来源：https://stackoverflow.com/questions/61023968/how-to-solve-handler-deprecated

标签

java

android

android-fragments

kotlin