我的服务器上的图像很少，其名称存储在 phpmysql 表中。该表包含两个字段：id 和 images。我准备了一个 php 来获取 json 编码格式的图像，如前所述：
jsonFetch.php
<?php
$dbhost = "localhost";
$dbname = "userauth";
$dbuser = "root";
//$DB_Pass = "root";
$dbtable = "images";
@mysql_connect($dbhost, $dbuser);
$db = mysql_select_db($dbname);
$sql = "SELECT * FROM $dbtable";
$query = mysql_query($sql);
while($row = mysql_fetch_array($query))
{
$rows[] = array(
//"id" => $row[0],
"image" => $row[1]
//"description" => $row['description']);
);
}
$json = json_encode($rows);
$callback = $_GET['images'];
echo $callback.$json ;
//print_r($json);
?>
现在，当我点击 url 时，我得到以下响应：
[{"image":"./95462"},{"image":"./8838upload_image.jpg"}{"image":"./43185upload_image.jpg"},{"image":"/17426upload_image.jpg "}]
我得到如上所述的json数组。
下一步就是在 UITableView 中以多线程的方式显示上面的数组。当我对它们进行硬编码时，我从 url 获取图像，但是当涉及到 json 解析时，我是一个菜鸟。我已经尝试了所有可以解析 json 的可能方式，以便您参考，我发布了 .m 文件。：
#import "json.h"
@interface profilePhotos(Private)
- (void) initialize;
- (void) loadImage:(id)arg;
- (void) updateTableView:(id)arg;
- (void) addImagesToQueue:(NSArray *)images;
- (void) addImagesToQueue:(NSArray *)arrayImages;
- (void) addImagesToQueue:(NSArray *)arrayDataFromServer;
- (void) showcommentView;
- (void) hidecommentView;
@end
@implementation profilePhotos
@synthesize photosTable;
@synthesize addPhotos;
@synthesize deletePhotos;
@synthesize back;
@synthesize imageQueue, loadedImages, imageLoaderOpQueue, commentView;
//@synthesize photosView;
-(void)initializeWith:(int)buttonTag{
tag = buttonTag;
NSLog(@"tag = %d", tag);
}
- (id) initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
if (!(self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
return self;
}
[self initialize];
return self;
}
- (void) awakeFromNib
{
NSLog(@"AsyncImageLoadingViewController::awakeFromNib called");
[super awakeFromNib];
[self initialize];
}
- (void) viewDidLoad
{
NSLog(@"AsyncImageLoadingViewController::viewDidLoad called");
[super viewDidLoad];
}
- (void) viewDidAppear:(BOOL)animated
{
NSLog(@"AsyncImageLoadingViewController::viewDidAppear called");
[super viewDidAppear:animated];
NSArray *images = [NSArray arrayWithObjects:
@"http://dl.dropbox.com/u/9234555/avatars/ava01.gif",
@"http://dl.dropbox.com/u/9234555/avatars/ava02.gif",
@"http://dl.dropbox.com/u/9234555/avatars/ava03.gif",
@"http://dl.dropbox.com/u/9234555/avatars/ava04.gif",
@"http://dl.dropbox.com/u/9234555/avatars/ava05.gif", nil];
[self addImagesToQueue:images];
NSLog(@"addImagesToQueue: %@",self);
}
#pragma mark -
#pragma mark Private Methods
/*!
@method
@abstract initializes class variables
*/
- (void) initialize
{
NSLog(@"AsyncImageLoadingViewController::initialize called");
NSMutableArray *a = [[NSMutableArray alloc] init];
self.imageQueue = a;
//[a release];
a = [[NSMutableArray alloc] init];
self.loadedImages = a;
//[a release];
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
self.imageLoaderOpQueue = queue;
//[queue release];
}
/*!
@method
@abstract updates tableview for the newly downloaded image and scrolls the tableview to bottom
*/
- (void) updateTableView:(id)arg
{
NSLog(@"AsyncImageLoadingViewController::updateTableView called");
if ((arg == nil) || ([arg isKindOfClass:[UIImage class]] == NO)) {
return;
}
// store the newly downloaded image
[self.loadedImages addObject:arg];
//[arg release];
// refresh tableview
[self.photosTable reloadData];
// scroll to the last cell of the tableview
NSIndexPath *lastRow = [NSIndexPath indexPathForRow:([self.loadedImages count] - 1) inSection:0];
[self.photosTable scrollToRowAtIndexPath:lastRow
atScrollPosition:UITableViewScrollPositionBottom
animated:YES];
}
/*!
@method
@abstract downloads images, this is the method that dispatches tasks in the operation q ueue
*/
- (void) loadImage:(id)arg
{
NSLog(@"AsyncImageLoadingViewController::loadImage called");
if ((arg == nil) || ([arg isKindOfClass:[NSString class]] == NO)) {
return;
}
// create a local autorelease pool since this code runs not on main thread
//NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
// fetch the image
NSLog(@"AsyncImageLoadingViewController::loadImage - will download image: %@", arg);
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:arg]];
UIImage *image = [UIImage imageWithData:data];
NSLog(@"image: %@",image);
// update tableview with the downloaded image on main thread
[self performSelectorOnMainThread:@selector(updateTableView:) withObject:image waitUntilDone:NO];
//[pool release];
}
/*!
@method
@abstract adds images to the queue and starts the operation queue to download them
*/
- (void) addImagesToQueue:(NSArray *)images
{
NSLog(@"AsyncImageLoadingViewController::addImagesToQueue called");
[self.imageQueue addObjectsFromArray:images];
NSLog(@"addImagesToQueue Array: %@", self);
// suspend the operation queue
[self.imageLoaderOpQueue setSuspended:YES];
// add tasks to the operation queue
for (NSString *imageUrl in self.imageQueue) {
NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(loadImage:) object:imageUrl];
[self.imageLoaderOpQueue addOperation:op];
// [op release];
}
// clear items in the queue and resume the operation queue to start downloading images
[self.imageQueue removeAllObjects];
[self.imageLoaderOpQueue setSuspended:NO];
}
#pragma mark -
#pragma mark UITableViewDataSource Methods
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section
{
return [self.loadedImages count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"CellIdentifier";
cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
//cell = [[[UITableViewCell alloc] initWithStyle:UITableViewStyleGrouped reuseIdentifier:CellIdentifier] autorelease];
cell = [[UITableViewCell alloc] initWithStyle:UITableViewStyleGrouped reuseIdentifier:[NSString stringWithFormat:@"cellID%d",indexPath.row]];
cell.accessoryType =UITableViewCellAccessoryNone;
//cell.accessoryType =UITableViewCellAccessoryDisclosureIndicator;
}
for(UIView *subviews in cell.subviews)
[subviews removeFromSuperview];
UIImageView *photo;
photo=[[UIImageView alloc] init];
[photo setImage:[self.loadedImages objectAtIndex:indexPath.row]];
[photo setFrame:CGRectMake(0, 5, 150, 120)];
[cell addSubview:photo];
return cell;
}
-(void)aMethod:(UIButton *)sender{
//[sender tag];
NSIndexPath *indexPath = [photosTable indexPathForCell: (UITableViewCell*)[[sender superview]superview]];
NSLog(@"[sender tag] is %d",[sender tag]);
if([sender tag]==indexPath.row){
textField = (UITextField*)[cell viewWithTag:[sender tag]];
textField.hidden=NO;
}
//}
}
#pragma mark -
#pragma mark UITableViewDelegate Methods
-(void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload{
// [self setPhotosView:nil];
[self setPhotosTable:nil];
[self setAddPhotos:nil];
[self setDeletePhotos:nil];
[self setBack:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:( UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
我相信需要在 viewDidAppear 方法中做一些事情，但我不明白它是什么。
请帮帮我。我已经尝试了所有可能的 json 方法。可能是我在这方面犯了一些错误，但我一直很沮丧。请帮帮我。