Implementation of the iPhone power-on Function

How does the iPhone implement the flashlight function?

First, define an avcapturesession instance object in the. h file.

Avcapturesession * torchsession;

 

Then, set the. M file as follows during initialization:

Avcapturedevice * capturedevice = [avcapturedevice defaultdevicewithmediatype: avmediatypevideo];

Avcapturedeviceinput * flashinput = [avcapturedeviceinput deviceinputwithdevice: capturedevice error: Nil];
Avcapturevideodataoutput * output = [[avcapturevideodataoutput alloc] init];

Avcapturesession * session = [avcapturesession alloc] init];

[Session beginconfiguration];
[Session addinput: flashinput];
[Session addoutput: output];

[Capturedevice lockforconfiguration: Nil];
Capturedevice. torchmode = avcapturetorchmodeon;
[Capturedevice unlockforconfiguration];

[Output release];
[Session commitconfiguration];
[Session startrunning];

[Self settorchsession: session];
[Session release];

 

Finally, the torchsession object is released in dealloc.