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Why is creating a Thread said to be expensive?
... there is a fair bit of work involved:
A large block of memory has to be allocated and initialized for the thread stack.
System calls need to be made to create / register the native thread with the host OS.
Descriptors need to be created, initialized and added to JVM-internal data structures.
It...
How do I use NSTimer?
...stance variable hasn't been set to nil and the NSTimer instance has been deallocated, it will throw an exception).
Note also the point on Memory Management at the bottom of the article:
Because the run loop maintains the timer, from the perspective of memory management there's typically no need...
How to embed small icon in UILabel
...tKit. Some sample code:
NSTextAttachment *attachment = [[NSTextAttachment alloc] init];
attachment.image = [UIImage imageNamed:@"MyIcon.png"];
NSAttributedString *attachmentString = [NSAttributedString attributedStringWithAttachment:attachment];
NSMutableAttributedString *myString= [[NSMutableAtt...
Array Length in Java
...
It contains the allocated size, 10. The unassigned indexes will contain the default value which is 0 for int.
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How can I detect the touch event of an UIImageView?
...in your .m file:
UITapGestureRecognizer *newTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(myTapMethod)];
[myImageView setUserInteractionEnabled:YES];
[myImageView addGestureRecognizer:newTap];
-(void)myTapMethod{
// Treat image tap
}
...
Easy way to concatenate two byte arrays
... is using java.nio.ByteBuffer.
Something like
ByteBuffer bb = ByteBuffer.allocate(a.length + b.length + c.length);
bb.put(a);
bb.put(b);
bb.put(c);
byte[] result = bb.array();
// or using method chaining:
byte[] result = ByteBuffer
.allocate(a.length + b.length + c.length)
.put(a...
R memory management / cannot allocate vector of size n Mb
...at is not a cure in general -- I've switched, and now I have Error: cannot allocate vector of size ... Gb instead (but yeah, I have a lot of data).
– om-nom-nom
Apr 11 '12 at 17:20
...
Quickly create a large file on a Linux system
... it is slow for this purpose. In Linux (and other POSIX systems), we have fallocate, which uses the desired space without having to actually writing to it, works with most modern disk based file systems, very fast:
For example:
fallocate -l 10G gentoo_root.img
...
SparseArray vs HashMap
...ypes, even though not all of them are publicly available.
Benefits are:
Allocation-free
No boxing
Drawbacks:
Generally slower, not indicated for large collections
They won't work in a non-Android project
HashMap can be replaced by the following:
SparseArray <Integer, Object>...
Make UINavigationBar transparent
...at colorMask[6] = {222, 255, 222, 255, 222, 255};
UIImage *img = [[UIImage alloc] init];
UIImage *maskedImage = [UIImage imageWithCGImage: CGImageCreateWithMaskingColors(img.CGImage, colorMask)];
[nav.navigationBar setBackgroundImage:maskedImage forBarMetrics:UIBarMetricsDefault];
[img release];
...