我有一个应用程序,从他们的联系人列表中选择一个人,并采取他们的名字,姓氏和电子邮件.然后它将第一个名称保存到nsmutablearray并将其放入uitableview单元格中.一旦在模拟器中选择了联系人,我的问题就出现了.
码：
.H：
#import <UIKit/UIKit.h> #import <AddressBookUI/AddressBookUI.h> @interface FirstViewController : UIViewController < ABPeoplePickerNavigationControllerDelegate,UITableViewDelegate,UITableViewDataSource> - (IBAction)showPicker:(id)sender; @property (weak,nonatomic) IBOutlet NSString *firstName; @property (weak,nonatomic) IBOutlet NSString *email; @property (weak,nonatomic) IBOutlet NSString *lastName; @property (weak,nonatomic) IBOutlet UITableView *myTableView; @property (strong,nonatomic) NSMutableArray *contacts; @end
.M：
#import "FirstViewController.h"
@interface FirstViewController ()
@end
@implementation FirstViewController
@synthesize firstName;
@synthesize email;
@synthesize lastName;
@synthesize contacts;
@synthesize myTableView;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view,typically from a nib.
contacts = [[NSMutableArray alloc]initWithObjects:nil];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - UITableView Datasource
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return contacts.count;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.textLabel.text = [contacts objectAtIndex:indexPath.row];
return cell;
}
- (IBAction)showPicker:(id)sender {
ABPeoplePickerNavigationController *picker =
[[ABPeoplePickerNavigationController alloc] init];
picker.peoplePickerDelegate = self;
[self presentModalViewController:picker animated:YES];
}
- (void)peoplePickerNavigationControllerDidCancel:
(ABPeoplePickerNavigationController *)peoplePicker
{
[self dismissModalViewControllerAnimated:YES];
}
- (BOOL)peoplePickerNavigationController:
(ABPeoplePickerNavigationController *)peoplePicker
shouldContinueAfterSelectingPerson:(ABRecordRef)person {
[self displayPerson:person];
[self dismissModalViewControllerAnimated:YES];
return NO;
}
- (BOOL)peoplePickerNavigationController:
(ABPeoplePickerNavigationController *)peoplePicker
shouldContinueAfterSelectingPerson:(ABRecordRef)person
property:(ABPropertyID)property
identifier:(ABMultiValueIdentifier)identifier
{
return NO;
}
- (void)displayPerson:(ABRecordRef)person
{
NSString* name = (__bridge_transfer NSString*)ABRecordCopyValue(person,kABPersonFirstNameProperty);
self.firstName = name;
NSString* last = (__bridge_transfer NSString*)ABRecordCopyValue(person,kABPersonLastNameProperty);
self.lastName = last;
ABMultiValueRef emails = ABRecordCopyValue(person,kABPersonEmailProperty);
NSString *emailId = (__bridge NSString *)ABMultiValueCopyValueAtIndex(emails,0);//0 for "Home Email" and 1 for "Work Email".
self.email = emailId;
if (!(contacts))
{
contacts = [[NSMutableArray alloc]init];
}
[contacts insertObject:firstName atIndex:0];
NSIndexPath * indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.myTableView insertRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}
@end
解决方法
UITableView必须始终与数据源保持同步.如果数据源可以在后台线程中更改,则必须特别小心.
当某些内容添加到数据源时,请尽快调用beginUpdate / insert / endUpdate.您不必担心缓存这些,UITableView会在确定有足够的cpu时间和资源时缓存要执行的更改.
调用endUpdates时,UITable将再次询问dataSource的节数和行数.如果直接来自dataSource的节和行的数量,则数字节和行,加上插入,减去删除必须等于numberOfSections和numberOfRowsInSection的结束调用返回的数字.
最后一个提示：避免混合调用’reloadData’和beginUpdate / endUpdate对.使用其中一个,而不是两个.
