private void postComment(){
    EditText nameEdit = (EditText)findViewById(R.id.edit_name);
    EditText commentEdit = (EditText)findViewById(R.id.edit_comment);
    String name = nameEdit.getText().toString();
    String comment = commentEdit.getText().toString();

    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost("http://example.com/data/feedmepostrequests.php");

    // set values you'd like to send
    List pairs = new ArrayList();
    pairs.add(new BasicNameValuePair("name", name));
    pairs.add(new BasicNameValuePair("comment", comment));
    pairs.add(new BasicNameValuePair("article_id", articleID));

    // you probably won't need these two lines below, but I have to work with web service
    // which has very annoying caching issues, so I usually pass some random argument
    // to avoid possible failure
    double r = Math.random();
    pairs.add(new BasicNameValuePair("rand", "r"+r));

    try {
        post.setEntity(new UrlEncodedFormEntity(pairs));
        // set ResponseHandler to handle String responses
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        String response = client.execute(post, responseHandler);
        Log.v("HttpPost", "Response: " + response);
        if (response.contains("SUCCESS")){
            // express your joy here!
        } else {
            // pop a sad Toast message here...
        }
    } catch (Exception e) {}
}

Disable animation on StartActivity

Before starting your activity, you have to set flag FLAG_ACTIVITY_NO_ANIMATION to your Intent.

Intent myIntent = new Intent();
myIntent.setClassName(this, ExampleActivity.class.getName());
myIntent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
startActivity(myIntent); 

Unfortunately, this will not disable animations caused by back button or, if you’ve started SubActivity, on finish().

Disable animation on finish() and back button pressed

After your finish() function put overridePendingTransition(0, 0):

Intent resultIntent = new Intent();
setResult(Activity.RESULT_OK, resultIntent);
finish();
overridePendingTransition(0, 0);

Same function helps with handling back button animation. Just override onBackPressed in your activity

	@Override
	public void onBackPressed() {
	  this.finish();
	  overridePendingTransition(0, 0);
	}

The actual code:

+ (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
    UIGraphicsBeginImageContext(newSize);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

Works like charm!

	NSArray *keyArray =  [bigUglyDictionary allKeys];
	int count = [keyArray count];
	for (int i=0; i < count; i++) {
		NSDictionary *tmp = [bigUglyDictionary objectForKey:[ keyArray objectAtIndex:i]];
	}

	NSEnumerator *enumerator = [bigUglyDictionary keyEnumerator];
	id key;
	while ((key = [enumerator nextObject])) {
		NSDictionary *tmp = [bigUglyDictionary objectForKey:key];
	}

Second way is a little bit faster, so if you work with huge dictionaries and have no need of array with their keys – use it.

Today I finally discovered CTFramesetterSuggestFrameSizeWithConstraints which can help with two important things: to get size of the frame you need for your CFAttributedString or to get how many characters of your string would fill frame with particular CGSize.

So, here is some code to illustrate different height results from both functions:

	//	test string
	NSString *text = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent pellentesque viverra est, molestie vehicula turpis consectetur sed. In hac habitasse platea dictumst. Maecenas vel dolor dolor, et hendrerit libero. Aliquam malesuada, erat vitae tempus tincidunt, ipsum tortor ultrices nunc, a rhoncus diam ligula nec purus. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec nec nisi libero. Phasellus viverra imperdiet urna. Ut mollis vulputate metus sed sollicitudin. Aenean viverra tellus vitae tortor placerat imperdiet. Integer porta magna ut mauris euismod in tincidunt justo ornare. Donec ac leo augue. Quisque luctus vehicula nisi id ornare. Pellentesque quis mi ac arcu semper cursus at eu purus. ";

	CGContextRef context = (CGContextRef)UIGraphicsGetCurrentContext();

	//	creating and formatting CFMutableAttributedString
	CFMutableAttributedStringRef attrStr = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
	CFAttributedStringReplaceString (attrStr, CFRangeMake(0, 0), (CFStringRef) text);
	CTFontRef font = CTFontCreateWithName(CFSTR("Times New Roman"), fontSize, NULL);
	CTTextAlignment alignment = kCTJustifiedTextAlignment;
	CTParagraphStyleSetting _settings[] = {	{kCTParagraphStyleSpecifierAlignment, sizeof(alignment), &alignment} };
	CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(_settings, sizeof(_settings) / sizeof(_settings[0]));
	CFAttributedStringSetAttribute(attrStr, CFRangeMake(0, CFAttributedStringGetLength(attrStr)), kCTParagraphStyleAttributeName, paragraphStyle);
	CFAttributedStringSetAttribute(attrStr, CFRangeMake(0, CFAttributedStringGetLength(attrStr)), kCTFontAttributeName, font);
	CFRelease(paragraphStyle);
	CFRelease(font);	

	CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attrStr);
	CFRelease(attrStr);

	int textLength = [text length];
	CFRange range;
	CGFloat maxWidth	= 100.0f;
	CGFloat maxHeight	= 10000.0f;
	CGSize constraint	= CGSizeMake(maxWidth, maxHeight);

	//	checking frame sizes
	CGSize labelSize	= [article.body sizeWithFont:[UIFont fontWithName:@"Times New Roman" size:16] constrainedToSize:constraint lineBreakMode:UILineBreakModeWordWrap];
	CGSize coreTextSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetter, CFRangeMake(0, textLength), nil, constraint, &range);	

	//	printing results
	NSLog(@"Label.sizeWithFont: %f x %f", labelSize.width, labelSize.height);
	NSLog(@"CoreText.SuggestFrameSize: %f x %f", coreTextSize.width, coreTextSize.height);
	NSLog(@"Character count in constraint frame: %d (total: %d)", range.length, textLength);

Results:

Label.sizeWithFont: 100.000000 x 1160.000000
CoreText.SuggestFrameSize: 100.000008 x 1059.507812
Character count in constraint frame: 718 (total: 718)

100px is significant difference and it increases proportionally with text size. Also to demonstrate CFRange usefulness I’ll use 100×100 constraint:

Label.sizeWithFont: 99.000000 x 100.000000
CoreText.SuggestFrameSize: 100.000000 x 84.390625
Character count in constraint frame: 66 (total: 718)

SuggestFrameSize results are interesting in this one. I guess, we get 84.39 height, because CoreText couldn’t fit another line, so updated constraint frame with REAL height.

In clearer terms aka code form:

//    create attributed string
 CFMutableAttributedStringRef attrStr = CFAttributedStringCreateMutable(kCFAllocatorDefault, 0);
 CFAttributedStringReplaceString (attrStr, CFRangeMake(0, 0), (CFStringRef) textString);

 //    create font
 CTFontRef font = CTFontCreateWithName(CFSTR("Times New Roman"), 16, NULL);

 //    create paragraph style and assign text alignment to it
 CTTextAlignment alignment = kCTJustifiedTextAlignment;
 CTParagraphStyleSetting _settings[] = {    {kCTParagraphStyleSpecifierAlignment, sizeof(alignment), &alignment} };
 CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(_settings, sizeof(_settings) / sizeof(_settings[0]));

 //    set paragraph style attribute
 CFAttributedStringSetAttribute(attrStr, CFRangeMake(0, CFAttributedStringGetLength(attrStr)), kCTParagraphStyleAttributeName, paragraphStyle);

 //    set font attribute
 CFAttributedStringSetAttribute(attrStr, CFRangeMake(0, CFAttributedStringGetLength(attrStr)), kCTFontAttributeName, font);

 //    release paragraph style and font
 CFRelease(paragraphStyle);
 CFRelease(font);

I’ve changed it a bit and after some trial and error managed to create working CoreText example, which puts text in two columns. Oh, and letters are proper side up – looks like CoreText and iPhone works in different coordinate system. Most important lines to fix this issue are:

CGContextTranslateCTM(context, 0, _columnHeight);
CGContextScaleCTM(context, 1.0, -1.0);

CGContextTranslateCTM – Changes the origin of the user coordinate system in a context. It’s important to set your columns and CGContextTranslateCTM argument to the same height. I’ve spent too much time trying to figure out why everything is messed up while my columns was much shorter then the height I was passing to this function.
CGContextScaleCTM – Changes the scale of the user coordinate system in a context.

Result before these coordinate changes:

Before that massive chunk of code, I just want to be clear, that I’ve declared some variables in .h file, so use your own:

_columnCount = 2;
_columnHeight = 300;

And full example bellow:

- (CFArrayRef)createColumns {
    CGRect bounds = CGRectMake(0, 0, 400, _columnHeight);
    int column;

    CGRect* columnRects = (CGRect*)calloc(_columnCount, sizeof(*columnRects));

    // Start by setting the first column to cover the entire view.
    columnRects[0] = bounds;

    // Divide the columns equally across the frame's width.
    CGFloat columnWidth = CGRectGetWidth(bounds) / _columnCount;

    for (column = 0; column < _columnCount - 1; column++) {
        CGRectDivide(columnRects[column], &columnRects[column],&columnRects[column + 1], columnWidth, CGRectMinXEdge);
    }

	//	add margin
    for (column = 0; column < _columnCount; column++) {
        columnRects[column] = CGRectInset(columnRects[column], 10.0, 10.0);

    }

	// Create an array of layout paths, one for each column.
    CFMutableArrayRef array = CFArrayCreateMutable(kCFAllocatorDefault, _columnCount, &kCFTypeArrayCallBacks);
    for (column = 0; column < _columnCount; column++) {
        CGMutablePathRef path = CGPathCreateMutable();
        CGPathAddRect(path, NULL, columnRects[column]);
        CFArrayInsertValueAtIndex(array, column, path);
        CFRelease(path);
    }

    free(columnRects);
    return array;
}

- (void)drawRect:(CGRect)rect {
    [[UIColor whiteColor] set];
	CGContextRef context = (CGContextRef)UIGraphicsGetCurrentContext();

    CGContextTranslateCTM(context, 0, _columnHeight);
    CGContextScaleCTM(context, 1.0, -1.0);

    [UIBezierPath bezierPathWithRect:[self bounds]];

	CFStringRef string = (CFStringRef) @"Long text.\n\nfoobarpig.com";
	CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(CFAttributedStringCreate(NULL, string, NULL));

    CFArrayRef columnPaths = [self createColumns];
    CFIndex pathCount = CFArrayGetCount(columnPaths);

    CFIndex startIndex = 0;

    int column;
    for (column = 0; column < pathCount; column++) {

        CGPathRef path = (CGPathRef)CFArrayGetValueAtIndex(columnPaths, column);

        // Create a frame for this column and draw it.
        CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(startIndex, 0), path, NULL);
        CTFrameDraw(frame, context);

        // Start the next frame at the first character not visible in this frame.
        CFRange frameRange = CTFrameGetVisibleStringRange(frame);
        startIndex += frameRange.length;
        CFRelease(frame);
    }
    CFRelease(columnPaths);
}

Final result:

Last thing: do not forget to add CoreText framework to your project and #import <CoreText/CoreText.h>. That’s all I guess.

So, in myTableViewController I created custom init function:

- (id) initWithFrame:(CGRect)frm {
	if ((self = [super initWithStyle: UITableViewStylePlain])){
		self.tableView = [[UITableView alloc] initWithFrame:frm style:UITableViewStylePlain];
	}
	return self;
}

Obviously, you can use default or your own init function or avoid passing frame argument and hardcode dimensions right here, but the magical line is:

self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(x, y, width, height) style:UITableViewStylePlain];

Well, at least it worked for me.

componentsSeparatedByString

NSString *exampleURL = @"http://foobarpig.com/iphone/";
NSArray *pieces = [exampleURL componentsSeparatedByString:@"/"];
NSLog(@"%@", pieces);

And result is a nice array of strings separated by “/”:

"http:",
"",
"foobarpig.com",
iphone,
""

componentsSeparatedByCharactersInSet

In cases, when you need to split your string by more than one separator, use componentsSeparatedByCharactersInSet function.

NSString *exampleURL = @"http://foobarpig.com/iphone/";
NSCharacterSet *charSet = [NSCharacterSet characterSetWithCharactersInString:@"/:."];  // note 3 separators: "/", ":" and "."
NSArray *pieces = [exampleURL componentsSeparatedByCharactersInSet:charSet];
NSLog(@"%@", pieces);

Result:

    http,
    "",
    "",
    foobarpig,
    com,
    iphone,
    ""

1. Get TouchXML

You can find archives to download in touchcode project downloads . Go to TouchCode github page and download TouchXML archive and extract it anywhere you like. It’s common practice to keep such libraries and classes in Developer/ExtraLibs directory.

2. Enable libxml2 library

First things first, before we actually add TouchXML files, we need to do some project configuration changes, so our project could use libxml library.

1. Go to “Project -> Edit project settings”

2. Activate “Build” tab

3. Search for “Header search paths” setting and add /usr/include/libxml2 value to it

4. Search for “Other linker flags” setting and add -lxml2 value

P.s. notice that search function is really useful for finding settings you need faster.

3. Add TouchXML classes

1. Right click (option click) on your projects “Classes” folder and go to “Add -> Existing files…”

2. Navigate to the directory where extracted TouchXML is kept and browse  deeper to “Common -> Source”. Select everything! And click “Add” obviously.

3. Confirm.

Now you should see a bunch of new files in your project. I usually group them by selecting files I wish to group and then selecting “Group” in context (right click/option click) menu.

4. Import TouchXML to your project

#import "TouchXML.h"

That is all the “magic” and you’re good to go. Since, I am not going to write about actually using TouchXML, you can see a nice working example in my previous post.

5. Common errors

Error: libxml/tree.h: No such file or directory

… and hundreds of something missing errors. It means that something went wrong with “Header search paths”. Maybe you didn’t added /usr/include/libxml2
or added incorrectly? Check it.

Error: “_xmlDocDumpFormatMemory”, referenced from:- [CXMLDocument description] in CXMLDocument.o

… and tens of errors like this. While errors by them selfs aren’t very expressive, they wish to inform you, that you did not added -lxml2 flag to “Other linker flags”

And that is all for now!