将textView作为视图的子视图并将此视图添加到视频

Question

我正在处理视频的应用程序中工作。在这个应用程序中，我想通过使用UITextView来为视频添加文本。为此我编程创建了UITextView，并将其添加为UIView这样的子视图。

[self.view addSubview:textView]; 

但只要我这个观点添加到视频像this--

[parentLayer addSublayer:textView]; 

我得到的错误，如this--

主题1：EXC_BAD_ACCESS（代码= 1地址= 0x18）

请帮我拿这个。以下是我已经完成的代码迄今为止实现这一目标。

-(void)displayTextInVideo 
{ 
if (!self.videoAsset) { 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"Please Load a Video Asset First" 
                delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; 
    [alert show]; 
    return; 
} 
AVMutableComposition* mixComposition = [AVMutableComposition composition]; 

AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid]; 
AVAssetTrack *clipVideoTrack = [[self.videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]; 
[compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, self.videoAsset.duration) 
           ofTrack:clipVideoTrack 
           atTime:kCMTimeZero error:nil]; 

[compositionVideoTrack setPreferredTransform:[[[self.videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] preferredTransform]]; 

CALayer *aLayer = [CALayer layer]; 
aLayer.frame = CGRectMake(0, 0, 30, 30); //Needed for proper display. We are using the app icon (57x57). If you use 0,0 you will not see it 
aLayer.opacity = 0.75; //Feel free to alter the alpha here 
//Create layer with watermark text instead of image 
CGSize videoSize = [self.videoAsset naturalSize]; 
UITextView *textView =[[UITextView alloc]init]; 
textView.frame=CGRectMake(0,0,282,210); 
[textView setReturnKeyType:UIReturnKeyDone]; 
[self.view addSubview:textView]; 
CALayer *parentLayer = [CALayer layer]; 
CALayer *videoLayer = [CALayer layer]; 

parentLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height); 
videoLayer.frame = CGRectMake(0, 0, videoSize.width, videoSize.height); 
[parentLayer addSublayer:videoLayer]; 
[parentLayer addSublayer:aLayer]; 
[parentLayer addSublayer:textView]; //ONLY IF WE ADDED TEXT 
//Create composition 
AVMutableVideoComposition* videoComp = [AVMutableVideoComposition videoComposition]; 
videoComp.renderSize = videoSize; 
videoComp.frameDuration = CMTimeMake(1, 30); 
videoComp.animationTool = [AVVideoCompositionCoreAnimationTool  videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer]; 
//Create instruction to insert layer 
AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction]; 
instruction.timeRange = CMTimeRangeMake(kCMTimeZero, [mixComposition duration]); 
AVAssetTrack *videoTrack = [[mixComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]; 
AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack]; 
instruction.layerInstructions = [NSArray arrayWithObject:layerInstruction]; 
videoComp.instructions = [NSArray arrayWithObject: instruction]; 

NSString *destPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)objectAtIndex:0]stringByAppendingPathComponent:@"NewwatermarkVideo.mp4"]; 
NSURL *exportUrl = [NSURL fileURLWithPath:destPath]; 



if ([[NSFileManager defaultManager] fileExistsAtPath:destPath]) 
{ 
    [[NSFileManager defaultManager] removeItemAtPath:destPath error:nil]; 
} 



AVAssetExportSession *exporter = [[AVAssetExportSession alloc] initWithAsset:mixComposition 
                    presetName:AVAssetExportPresetHighestQuality]; 
exporter.outputURL=exportUrl; 
exporter.outputFileType = AVFileTypeQuickTimeMovie; 
exporter.shouldOptimizeForNetworkUse = YES; 
exporter.videoComposition = videoComp; 
[exporter exportAsynchronouslyWithCompletionHandler:^{ 
    dispatch_async(dispatch_get_main_queue(), ^{ 
     [self exportDidFinish:exporter]; 
    }); 
}]; 
} 

任何帮助将不胜感激。

Answer 1

您不能将UIView子类添加为图层实例的子图层。尝试

[parentLayer addSublayer:textView.layer]; 

由于添加子图层时类型不匹配而导致访问不良。所需类型的参数是UILayer子类，但是您使用UIView代替。

希望这会有所帮助。

Answer 2

CGSize videoSize; //vedio size goes here 

CATextLayer *titleLayer = [CATextLayer layer]; 
titleLayer.string = @"Text goes here"; 

titleLayer.fontSize = videoSize.height/6; 

titleLayer.alignmentMode = kCAAlignmentCenter; 
titleLayer.bounds = CGRectMake(0, 0, videoSize.width, videoSize.height/6); //You may need to adjust this for proper display 

将此标题图层添加到parentLayer。

希望这将有助于:)