Question

Match each of these tasks with the classes that perform them. Some answers may be used more than once. Obtain a task request to be sent from a different thread A. Message Queue and to be performed by this thread. B. Message Accept a new task request, then store it in another class C. Handler until this thread has time to perform the task. D. Looper Remove the top task request from the class that is storing it when the thread has time to perform that next task. Send the task request to the class that will perform it. Has indication of the task to be performed and any data needed to perform it. Hold a list of task requests until they can be run. Peform the requested task.

Answer 1

Solution 4 -

4.1 Handler Obtains a task request to be sent from a different thread and to be performed by this thread.

           Explanation :- Handler recieves messages/request to be executed by this thread and then store them in the MessageQue of this thread

4.2 Handler - Accept a new task request, then store it in another class until this thread has the time to perform the task.

          Explanation :- Handler recieves messages/request to be executed by this thread and then store them in the MessageQue of this thread

4.3 Looper remove the top task request from the class that is storing it when the thread has time to perform that next task.

          Explanation :- Looper in each its iteration reads the next message using Looper.loop() method and dispatch it to target Handler

4.4 Looper Send the task request to the class that will peform it.

         Explanation :- Again, Looper in each its iteration reads the next message using Looper.loop() method and dispatch it to target Handler

4.5 Message Has indication of the task to be performed and any data needed to perform it.

        Explanation :- The Message acts as a container for arbitrary data which is required to perform the task.

4.6 MessageQueue Hold a list of task requests until they can be run.

       Explanation :- Message Queue holds all the messages/tasks needed to be performed on this thread

4.7 Handler - Perform the requested task

       Explanation :- The requested task is performed by the target handler of this thread.

Explanations given can be visualized and well understood from the following flow diagram:

mg Handler Looper New message Append message to message Queue Dispatch to handler for processing me, m3, m2, m, Retrieve Message

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