- (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:@"cell"];
if( nil == cell ) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:@"cell"] autorelease];
}
Fruits *fruit = [fruits objectAtIndex:indexPath.row];
cell.textLabel.text = fruit.fruitName;
//start of important code for background color changes
cell.textLabel.backgroundColor = [UIColor clearColor];
UIView *bgColor = [cell viewWithTag:100];
if (!bgColor) {
CGRect frame = CGRectMake(0, 0, 320, 44);
bgColor = [[UIView alloc] initWithFrame:frame];
bgColor.tag = 100; //tag id to access the view later
[cell addSubview:bgColor];
[cell sendSubviewToBack:bgColor];
[bgColor release];
}
if (indexPath.row % 2 == 0){
bgColor.backgroundColor = [UIColor colorWithRed:233.0/255.0
green:233.0/255.0
blue:233.0/255.0
alpha:1.0];
} else {
bgColor.backgroundColor = [UIColor clearColor];
}
//end of important code
return cell;
}
cell.textLabel.backgroundColor = [UIColor clearColor];This line makes sure your cell text has an transparent background, otherwise you end up with a result like in the screenshot below.
UIView *bgColor = [cell viewWithTag:100];
if (!bgColor) {
CGRect frame = CGRectMake(0, 0, 320, 44);
bgColor = [[UIView alloc] initWithFrame:frame];
bgColor.tag = 100; //tag id to access the view later
[cell addSubview:bgColor];
[cell sendSubviewToBack:bgColor];
[bgColor release];
}
First we check if the cell has already a view with tag id 100. If not, create a new view with the size of the cell(standard 320x44). Then the view gets add to the cell and send to the background.if (indexPath.row % 2 == 0){
bgColor.backgroundColor = [UIColor colorWithRed:233.0/255.0
green:233.0/255.0
blue:233.0/255.0
alpha:1.0];
} else {
bgColor.backgroundColor = [UIColor clearColor];
}
If the cell index is even (0, 2, 4, etc.) the background color of the background color view is set to grey. Else it is set to clear (white). if (indexPath.row % 2 == 0){
...
// RootViewController.h
#import <UIKit/UIKit.h>
@class GTMHTTPFetcher;
@interface RootViewController : UIViewController <UINavigationControllerDelegate> {
int networkActivityCounter;
...
}
- (void)startFetchingData;
- (void)fetchData:(GTMHTTPFetcher *)fetcher finishedWithData:(NSData *)retrievedData error:(NSError *)error;
@end
// RootViewController.m
- (void)viewDidLoad{
//add observer for fetcher start and stop events
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:@selector(incrementNetworkActivity:) name:kGTMHTTPFetcherStartedNotification object:nil];
[nc addObserver:self selector:@selector(decrementNetworkActivity:) name:kGTMHTTPFetcherStoppedNotification object:nil];
...
}
#pragma mark Network activity
- (void)incrementNetworkActivity:(NSNotification *)notify {
++networkActivityCounter;
if (1 == networkActivityCounter) {
UIApplication *app = [UIApplication sharedApplication];
[app setNetworkActivityIndicatorVisible:YES];
}
}
- (void)decrementNetworkActivity:(NSNotification *)notify {
--networkActivityCounter;
if (0 == networkActivityCounter) {
UIApplication *app = [UIApplication sharedApplication];
[app setNetworkActivityIndicatorVisible:NO];
}
}
- (void)dealloc {
//remove the observer
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc removeObserver:self];
...
[super dealloc];
}
//the String with the original text
NSString *unfilteredString = @"The sum of 1 + 2 = 3.";
//initialize a string that will hold the result
NSMutableString *resultString = [NSMutableString stringWithCapacity:unfilteredString.length];
NSScanner *scanner = [NSScanner scannerWithString:unfilteredString];
//define the allowed characters, here only numbers from one to three, equal and plus
NSCharacterSet *allowedChars = [NSCharacterSet characterSetWithCharactersInString:@"123+="];
while ([scanner isAtEnd] == NO) {
NSString *buffer;
if ([scanner scanCharactersFromSet:allowedChars intoString:&buffer]) {
[resultString appendString:buffer];
} else {
[scanner setScanLocation:([scanner scanLocation] + 1)];
}
}
//Print out the result String, will be 1+2=3
NSLog (@"Result: %@", resultString);
Example org.eclipse.wst.jsdt.core.javascriptValidator org.eclipse.jdt.core.javabuilder org.eclipse.wst.common.project.facet.core.builder org.eclipse.wst.validation.validationbuilder org.eclipse.jem.workbench.JavaEMFNature org.eclipse.wst.common.modulecore.ModuleCoreNature org.eclipse.wst.common.project.facet.core.nature org.eclipse.jdt.core.javanature org.eclipse.wst.jsdt.core.jsNature
Make sure that in the last column of the list for each .m file (especially for the once that caused the error) the box is checked. If the box is checked the file is included in the default target that gets build.