Android Asynctask Analytics Internal implementation

Reprinted from: http://blog.csdn.net/jjwwmlp456/article/details/38623563

sdk3.0, using the internal thread pool, multithreading concurrently executes. Thread pool size equals 5, up to 128

After sdk3.0, a thread is executed using the default serial thread pool, and the next thread is executed sequentially. Sdk3.0<=current version <= sdk4.3 when the thread pool size equals 5, up to 128

sdk4.4 thread pool size equals CPU Count + 1, max CPU count * 2 + 1

There are two implementations of the thread pool after sdk3.0, and the default is the Serial thread pool

1  Public Static FinalExecutor Serial_executor =NewSerialexecutor (); 2  Public Static FinalExecutor Thread_pool_executor3=NewThreadpoolexecutor (core_pool_size, Maximum_pool_size, Keep_alive,4 timeunit.seconds, Spoolworkqueue, sthreadfactory); 5 Private Static volatileExecutor Sdefaultexecutor =Serial_executor; 6  Public Static voidSetdefaultexecutor (Executor exec) {//set the default thread pool7Sdefaultexecutor =exec; 8}

Serialexecutor, using a synchronous lock, execute one thread at a time

1 Private Static classSerialexecutorImplementsExecutor {2         FinalArraydeque<runnable> Mtasks =NewArraydeque<runnable>(); 3 Runnable mactive; 4   5          Public synchronized voidExecuteFinalRunnable R) {  6Mtasks.offer (NewRunnable () {7                  Public voidrun () {8                     Try {  9 R.run (); Ten}finally {   One Schedulenext ();  A                     }   -                 }   -             });  the             if(Mactive = =NULL) {   - Schedulenext ();  -             }   - }   +    -         protected synchronized voidSchedulenext () { +             if((mactive = Mtasks.poll ())! =NULL) {   A Thread_pool_executor.execute (mactive);  at             }   -         }   -}

Thread_pool_executor Concurrent Thread pool

Asynctask.setdefaultexecutor (Asynctask.thread_pool_executor); Set up to use the concurrency thread pool

The params is used in the doinbackground (params ... params);

Asynctask.executeonexecutor (executor, params); You can customize the thread pool using both of these methods

Android Asynctask Analytics Internal implementation