当我离开应用程序并回到它的“开启”状态时，有时它可以通过打开手电筒/闪光灯正常工作，但大多数时候它要么闪烁要么保持关闭。
应用代理.m
- (id) init {
torchState = TRUE;
if( (self=[super init] )) {
/// initialize flashlight
// test if this class even exists to ensure flashlight is turned on ONLY for iOS 4 and above
Class captureDeviceClass = NSClassFromString(@"AVCaptureDevice");
if (captureDeviceClass != nil) {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch] && [device hasFlash]){
if (device.torchMode == AVCaptureTorchModeOff) {
NSLog(@"Setting up flashlight for later use...");
AVCaptureDeviceInput *flashInput = [AVCaptureDeviceInput deviceInputWithDevice:device error: nil];
AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc] init];
AVCaptureSession *session = [[AVCaptureSession alloc] init];
[session beginConfiguration];
[device lockForConfiguration:nil];
[session addInput:flashInput];
[session addOutput:output];
[device unlockForConfiguration];
[output release];
[session commitConfiguration];
[session startRunning];
[self setTorchSession:session];
[session release];
}
}
}
}
return self;
}
- (void)toggleTorch {
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
// For the first 4 to 5 times comming back from multiask this first if hits and works properly
if (torchState == TRUE && device.torchMode == AVCaptureTorchModeOff) {
NSLog(@"AVCaptureTorchModeOff setting On");
// On the 4th or 5th time it flashes and stays off or does nothing staying OFF
// even though the NSLog fires
[device setTorchMode:AVCaptureTorchModeOn];
[device setFlashMode:AVCaptureFlashModeOn];
} else if (torchState == TRUE && device.torchMode == AVCaptureTorchModeOn) {
// Sometimes this randomly fires and every time ErrorNotification fires too
NSLog(@"AVCaptureTorchModeOn");
if (AVCaptureSessionRuntimeErrorNotification) {
NSLog(@"ERROR");
// Try to force but doesn't do anything
[device setTorchMode:AVCaptureTorchModeOn];
[device setFlashMode:AVCaptureFlashModeOn];
}
} else {
NSLog(@"ALL IS OFF");
// when torch is in the off state it returns off as it should
torchState = FALSE;
[device setTorchMode:AVCaptureTorchModeOff];
[device setFlashMode:AVCaptureFlashModeOff];
}
[device unlockForConfiguration];
}
-(void) applicationDidEnterForeground:(UIApplication*)application {
[self toggleTorch];
}
我唯一没有包含在代码中的是一个触摸，即使它调用 toggleTorch 进行开/关。那件作品再次很棒，我在这里测试的是在启动时打开它，也就是 DidEnterForeground 以及当应用程序从多任务会话返回时。