【发布时间】：2012-07-20 12:25:00
【问题描述】：
您好，我有一些最有效的代码。它基本上以淡入淡出的效果对数组中的图像数量进行动画处理。
基本上一切正常，但是我有一个小错误，当视图第一次加载 第一个图像时，数组中似乎旋转了 90 度到正确的位置然后淡出到相同的图像，但看到这样的动画很烦人。所有从图像到另一个图像的褪色都是完美的，只是上面提到的错误。如前所述，仅在首次加载时。
这里是代码。 images 是 MutableArray，topImageView 和 bottomImageView 都是 ivars 和 ** 合成的**。 images 数组也是如此。
int topIndex = 0, bottomIndex = 1;
-(void)imageFader{
self.imageViewBottom = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 370)];
[self.view addSubview:imageViewBottom];
[imageViewBottom setAlpha:0.0];
[imageViewBottom release];
self.imageViewTop = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 370)];
[self.view addSubview:imageViewTop];
[imageViewTop setAlpha:1.0];
[imageViewTop release];
[imageViewTop setImage:[images objectAtIndex:topIndex]];
timer = [NSTimer timerWithTimeInterval:1.0
target:self
selector:@selector(onTimer)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
[timer fire];
}
-(void)onTimer{
[UIView animateWithDuration:1 animations:^{
//set the image of the image that is not currently visible
if (imageViewTop.alpha == 0) {
[imageViewTop setImage:[images objectAtIndex:topIndex]];
}
if (imageViewBottom.alpha == 0) {
[imageViewBottom setImage:[images objectAtIndex:bottomIndex]];
}
//make sure the images rotate
[imageViewTop setAlpha:imageViewTop.alpha == 0 ? 1 : 0];
[imageViewBottom setAlpha:imageViewBottom.alpha == 0 ? 1 : 0];
//make sure the images play in a loop
topIndex = topIndex < [images count]-1 ? bottomIndex+1 : 0;
bottomIndex = bottomIndex < [images count]-1 ? bottomIndex+1 : 0;}];
}
这是在将图像加载到动画的MutableArray 之前如何将图像保存到 docs 目录的方式。
-(void) imagePickerController:(UIImagePickerController *) picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {
UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
NSMutableDictionary *metadata = [[NSMutableDictionary alloc] init];
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
//Save to camera roll
[library writeImageToSavedPhotosAlbum:[image CGImage] orientation:(ALAssetOrientation) ALAssetOrientationRight completionBlock:^(NSURL *assetURL, NSError *error) { NSLog(@"completionBlock");
}];
int imageNumber = 0;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *pathToFile;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
do
{
// increment the image
imageNumber++;
// get the new path to the file
pathToFile = [documentsDirectory stringByAppendingPathComponent:
[NSString stringWithFormat:
@"standingImage%d.JPG", imageNumber]];
}
while([fileManager fileExistsAtPath:pathToFile]);
/* so, we loop for as long as we keep coming up with names that already exist */
UIImage *image2 = image; // imageView is my image from camera
//Use UIImageJPEGRepresentation to maitain image orientation!
NSData *imageData = UIImageJPEGRepresentation(image2, 0.9);
[imageData writeToFile:pathToFile atomically:NO];
[self dismissModalViewControllerAnimated:YES];
【问题讨论】：
-
您从哪里加载实际图像？这些 PNG 在您的捆绑包中吗？请添加执行此操作的相关代码。
-
@stavash 嗨，对不起，我应该提到这些图像是从 imagePicker（相机）保存到文档目录的，并且图像被保存为 JPGS，以在拍摄图像时保持正确的方向.然后从 docs 目录加载它们并添加到上面提到的名为 images 的可变数组中。
-
有人知道一张图片发生了什么吗？
标签： ios uiimageview core-animation nstimer nsrunloop