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Android - Basic Steps (Thread)

Thread

  • UI Thread - Is the main thread
  • UI Toolkit is not thread-safe

Methods

The following methods allows to  run in the UI Thread 
  • View.post(Runnable r)
  • Activity.runOnUiThread(Runnable r)

AsyncTask

Manage the Backgroud Thread & UI Thread
Used for relative short tasks that lasting few seconds

  • Background Thread
    • Performs work
    • Indicate progress
  • UI Thread
    • Does Setup
    • Publishes intermediate progress
    • Uses Results

Workflow

  • onPreExecute()
    • Run in UI Thread before doInBackground()
    • Do the setup
  • doInBackground()
    • Do the work in the background
    • Return the result in a Result object
  • pulishProgress()
    • This method may be invoked
  • onProgressUpdate()
    • If pulishProgress() is invoked then this method continue
    • Runs in the UI Thread
  • onPostExecute
    • Runs after doInBackground()


Handler

  • Handle two threads of any kind
  • One thread can hand off work to another thread by messages & posting runnables to handler associated with the second thread

Elements

  • Runnable 
    • Contains an instance of the Runnable instance
    • Sender implements response
  • Message
    • Contains
      • Message code
      • Object & Integer arguments








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