系统：4.0.3
1.启动时：
onCreate ->onWindowAttributesChanged(多次) -> onStart -> onResume -> onAttachedToWindow -> onWindowFocusChanged
2. 按后退键时：
onPause -> onWindowFocusChanged -> onStop -> onDestroy
3. 按Home键时：
onUserLeaveHint -> onPause -> onWindowFocusChanged -> onSaveInstanceState -> onStop
4. 按Home键后返回程序
onRestart -> onStart -> onResume ->onWindowFocusChanged
4. 按电源键熄灭屏幕时：
onPause -> onWindowFocusChanged -> onSaveInstanceState -> onStop
5. 按电源键重新点亮屏幕(不解锁)
onRestart -> onStart -> onResume
6. 解锁
onWindowFocusChanged