This is a simple Context use table
| 功能 | Application | Service | Activity |
|---|---|---|---|
| Starty an Activity | NO1 | NO1 | YES |
| Show a Dialog | NO | NO | YES |
| Layout Inflation | YES | YES | YES |
| Start a Service | YES | YES | YES |
| Bind to a Service | YES | YES | YES |
| Send a Broadcast | YES | YES | YES |
| Eegister BroadcastReceiver | YES | YES | YES |
| Load Resource Values | YES | YES | YES |
注：NO1标示Application和Service可以启动一个Activity,不过需要创建一个新的task任务栈。而对于Dialog而言，只有在Activity中才能创建