我是 iOS 新手，所以不要羞于指出我的任何看起来完全白痴的代码 :)
开始...
两个视图控制器 - OrderViewController 和 LineItemViewController - 当用户在 LineItemViewController 上时，他们可以单击“扫描”按钮，向服务器发送请求以将此项目标记为已扫描。这似乎工作正常，但我在控制台应用程序中收到此错误：
2013 年 5 月 19 日上午 11:28:04.044 EvoScanner：tcp_connection_destination_fail net_helper_connect_fail 失败
收到该错误后，该应用程序仍然可以正常运行。问题是当我单击“返回”返回 OrderViewController 时，应用程序因 EXC_BAD_ACCESS(code=1) 而崩溃。
我正在使用启用了 ARC 的 XCode 4.6.2。
这是我的 LineItemViewController：
// Interface
#import <UIKit/UIKit.h>
#import "LineItemModel.h"
@interface LineItemViewController : UIViewController
@property (strong, nonatomic) LineItemModel* _line_item;
-(void)setDetailItem:(LineItemModel *) lineItem;
@property (strong, nonatomic) IBOutlet UIButton *scanButton;
- (IBAction)scanItem:(id)sender;
@property (strong, nonatomic) IBOutlet UILabel *itemLabel;
-(IBAction)scanItem;
@end
// Implementation
#import "LineItemViewController.h"
#import "LineItemModel.h"
#import "HUD.h"
#import "JSONModelLib.h"
@interface LineItemViewController () {
LineItemModel *_line_item;
}
@end
@implementation LineItemViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.itemLabel.text = _line_item.product_title;
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)setDetailItem:(id)lineItem {
if(_line_item != lineItem) {
_line_item = lineItem;
[self configureView];
}
}
- (void)configureView
{
// Update the user interface for the detail item.
if (self._line_item) {
// self.detailDescriptionLabel.text = [self.detailItem description];
}
}
- (IBAction)scanItem:(id)sender {
NSLog(@"Scanning!");
NSString *string_url = [NSString stringWithFormat:(NSString *)@"%@/%@", @"http://localhost:3000/api/scan_item", _line_item.id ];
NSURL *url = [NSURL URLWithString:string_url];
NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url];
NSString *messageBody = [NSString stringWithFormat:@"status=%@",@1];
NSString *msgLength = [NSString stringWithFormat:@"%d", [messageBody length]];
[theRequest setHTTPMethod:@"POST"];
[theRequest addValue: msgLength forHTTPHeaderField:@"Content-Length"];
[theRequest setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[theRequest setHTTPBody:[messageBody dataUsingEncoding:NSUTF8StringEncoding]];
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if(theConnection)
{
NSLog(@"Connection Successful");
//receivedData = [[NSMutableData data] retain];
}
else
{
NSLog(@"There was an error: ");
// UIAlertView *alert1 = [[[UIAlertView alloc] initWithTitle:@"Alert" message:@"There was an issue sending the data. Please check your internet connection." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil] autorelease];
// [alert1 show];
}
}
@end
和 OrderViewController：
// Interface
#import <UIKit/UIKit.h>
#import "OrderModel.h"
@interface OrderViewController : UITableViewController
@property (strong, nonatomic) OrderModel* _order;
@property (strong, nonatomic) id detailItem;
@end
// Implementation
#import "OrderViewController.h"
#import "OrderModel.h"
#import "LineItemModel.h"
#import "LineItemCell.h"
#import "HUD.h"
#import "JSONModelLib.h"
#import "LineItemViewController.h"
@interface OrderViewController () {
OrderModel* _order;
NSMutableArray* listOfItems;
}
@end
@implementation OrderViewController
-(void)viewDidAppear:(BOOL)animated
{
NSLog(@"View did appear");
// show loader view
//[HUD showUIBlockingIndicatorWithText:@"Fetching order"];
//Initialize the array.
listOfItems = [[NSMutableArray alloc] init];
NSMutableArray *unPackedArray = [NSMutableArray array];
NSMutableArray *packedArray = [NSMutableArray array];
NSLog(@"ORDER: %@", _order);
for(int i = 0; i < _order.line_items.count; i++) {
NSLog(@"object in for loop: %@", _order.line_items[i]);
LineItemModel *li = _order.line_items[i];
if (li.qty_packed != li.quantity) {
[unPackedArray addObject:(LineItemModel *)_order.line_items[i]];
} else {
[packedArray addObject:(LineItemModel *)_order.line_items[i]];
}
}
NSLog(@"unpacked array: %@", unPackedArray);
NSLog(@"packed array: %@", packedArray);
NSDictionary *unPackedDict = [NSDictionary dictionaryWithObject:unPackedArray forKey:@"LineItems"];
NSDictionary *packedDict = [NSDictionary dictionaryWithObject:packedArray forKey:@"LineItems"];
[listOfItems addObject:unPackedDict];
[listOfItems addObject:packedDict];
// TODO: set the order id from the selected cell here
[self.tableView reloadData];
self.navigationItem.title = _order.customer_name;
}
- (void)setDetailItem:(id)newDetailItem
{
NSLog(@"MAKE DETAIL ITEM");
if (_order != newDetailItem) {
_order = newDetailItem;
// Update the view.
[self configureView];
}
// show loader view
[HUD showUIBlockingIndicatorWithText:@"Fetching order"];
NSString *order_id = _order.id;
NSString *url = [NSString stringWithFormat:(NSString *)@"%@/%@.%@", @"http://localhost:3000/api/order", order_id, @"json" ];
_order = [[OrderModel alloc] initFromURLWithString:url completion: ^(JSONModel *model, JSONModelError *err) {
// hide loader view
[HUD hideUIBlockingIndicator];
[self.tableView reloadData];
}];
}
- (void)configureView
{
// Update the user interface for the detail item.
if (_order) {
// self.detailDescriptionLabel.text = [self.detailItem description];
}
}
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
NSLog(@"View DID LOAD");
[super viewDidLoad];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
#warning Potentially incomplete method implementation.
// Return the number of sections. One for Packed items, one for items not packed.
return [listOfItems count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
NSDictionary *dictionary = [listOfItems objectAtIndex:section];
NSArray *array = [dictionary objectForKey:@"LineItems"];
return [array count];
}
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// NSLog(@"ORDER IN LINEITEM CELL: %@", _order);
// NSLog(@"LINEITEM: %@", line_item);
// New view code with subclass
LineItemCell *cell = (LineItemCell *)[tableView dequeueReusableCellWithIdentifier:@"LineItemCell"];
if (!cell) {
cell = [[LineItemCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"LineItemCell"];
}
// Get the Line Item object for this row and section
NSDictionary *dictionary = [listOfItems objectAtIndex:indexPath.section];
NSArray *array = [dictionary objectForKey:@"LineItems"];
LineItemModel* line_item = [array objectAtIndex:indexPath.row];
cell.productLabel.text = line_item.product_title;
cell.variantLabel.text = line_item.variant_title;
int remaining = line_item.quantity - line_item.qty_packed;
cell.remainingLabel.text = [NSString stringWithFormat:@"%i", remaining];
// NSLog(@"LINE ITEM CELL: %@", cell);
return cell;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
if(section == 0)
return @"Unpacked Items";
else
return @"Packed Items";
}
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
#pragma mark - Table view delegate
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
NSDictionary *dictionary = [listOfItems objectAtIndex:indexPath.section];
NSArray *array = [dictionary objectForKey:@"LineItems"];
LineItemModel *li = [array objectAtIndex:indexPath.row];
NSLog(@"Line Item in final: %@", li);
LineItemViewController *vc = [segue destinationViewController];
[vc setDetailItem:li];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Navigation logic may go here. Create and push another view controller.
/*
<#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
*/
}
@end
更新：为所有异常设置断点后，跟踪引导我：
#import <UIKit/UIKit.h>
#import "EvoAppDelegate.h"
int main(int argc, char *argv[])
{
@autoreleasepool {
// Breakpoint leads to this line
// Thread 1: EXC_BAD_ACCESS(code=1, ...)
return UIApplicationMain(argc, argv, nil, NSStringFromClass([EvoAppDelegate class]));
}
}