资料摘自网络（侵删）
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Service
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Thread
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IntentService
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AsyncTask
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When to use ?
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Task with no UI, but shouldn't be too long. Use threads within service for long tasks.
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- Long task in general.
- For tasks in parallel use Multiple threads (traditional mechanisms) |
- Long task usually with no communication to main thread.
(Update)- If communication is required, can use main thread handler or broadcast intents - When callbacks are needed (Intent triggered tasks). |
- Small task having to communicate with main thread.
- For tasks in parallel use multiple instances OR Executor |
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Trigger
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Call to method
onStartService() |
Thread start() method
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Intent
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Call to method execute()
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Triggered From (thread)
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Any thread
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Any Thread
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Main Thread (Intent is received on main thread and then worker thread is spawed)
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Main Thread
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Runs On (thread)
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Main Thread
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Its own thread
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Separate worker thread
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Worker thread. However, Main thread methods may be invoked in between to publish progress.
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Limitations /
Drawbacks |
May block main thread
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- Manual thread management
- Code may become difficult to read |
- Cannot run tasks in parallel.
- Multiple intents are queued on the same worker thread. |
- one instance can only be executed once (hence cannot run in a loop)
- Must be created and executed from the Main thread |