小提醒：在block中如果要改UI顯示，要記得用回main thread

//block會另開一個thread去跑，所以如果要顯示UI，要記得用GCD改原main thread

dispatch_async(dispatch_get_main_queue(), ^{

                cell.textLabel.text = device.name;

            });

UITableView的單選機制

//先在class中宣告一個全域變數int _selectedIndex = 0;

#pragma mark - UITableView Delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

    /*

     *  @單選機制

     */

    //取消前一個選取的

    NSIndexPath *lastIndex = [NSIndexPath indexPathForRow:_selectedIndex inSection:0];

    UITableViewCell *lastCell = [tableView cellForRowAtIndexPath:lastIndex];

    //lastCell.accessoryType = UITableViewCellAccessoryNone;

    lastCell.accessoryView = nil;

//取消所有目前看的到的Cell的(可以取代上面的區塊)

NSArray *visibleCells = [tableView visibleCells];

    for(UITableViewCell *_eachCell in visibleCells)

    {

        //_eachCell.accessoryType = UITableViewCellAccessoryNone;

        _eachCell.accessoryView = nil;

    }

    

    //選取的

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    //cell.accessoryType = UITableViewCellAccessoryCheckmark;

    cell.accessoryView = button;

    

    //存入這筆選到的

    _selectedIndex = indexPath.row;

    //0.5秒後移除cell被選取時的效果

    [tableView performSelector:@selector(deselectRowAtIndexPath:animated:) withObject:indexPath afterDelay:.5];

}

Storeboard用segue切換viewController

一般是直接用storyboard把圖上的segue拉好，不用加程式碼。

但也可以如下列程式碼用performSegueWithIdentifier

-(void)buttonAction:(id)sender
{
    [self performSegueWithIdentifier:@"MySegueName" sender:sender];
}

//在執行上面的method之後，會先進來這個method，你可以在此把值pass進去

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"MySegueName"]) 
    {
        NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
        NSDate *object = _objects[indexPath.row];
        [[segue destinationViewController] setDetailItem:object];
    }
}

判斷是否有開啟網路

先下載這個Library

https://gist.github.com/darkseed/1182373

- (void)viewDidLoad {
    Reachability *internetReach = [[Reachability reachabilityForInternetConnection] retain];
    [internetReach startNotifer];
    Reachability *wifiReach = [[Reachability reachabilityForLocalWiFi] retain];
    [wifiReach startNotifer];

    NetworkStatus netStatus1 = [internetReach currentReachabilityStatus];
    NetworkStatus netStatus2 = [wifiReach currentReachabilityStatus];
    if(netStatus1 == NotReachable && netStatus2 == NotReachable)
    {
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Sorry" message:@"This feature requires an internet connection." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alertView show];
        [alertView release];
    }
    else
    {//wifi connection available;
}
}

實作property的getter跟setter

@interface BLEManager : NSObject{
    CBPeripheral* _activePeripheral;
}



//實作activePeripheral的getter

-(CBPeripheral*) activePeripheral{

    return _centralController.activePeripheral;

}

//實作activePeripheral的setter

-(void) setActivePeripheral:(CBPeripheral *)activePeripheral{

    _activePeripheral = activePeripheral;

}

Note.實作完之後，就要手動完成property的其他事情。

bluetooth ble開發經驗

1.Scan到的peripheral一定要先把它指向一個strong CBPeripheral Property

2.這個strong Property不能去new它，不然就會出現用zombie也找不到的error

3.iOS跟android都不一定會收到所有的廣播，例如固定device每4秒發一次廣播，iOS實際收到的頻率可能是4,4,16,4,8,12,4,4,4,68,4,4，用lightBlue app看也是如此。

4.
-(id)init {
self = [super init];
if ( self )
{
//創一個thread專門給CentralManager使用
_centralQueue = dispatch_queue_create("forCentralManagerOnly", DISPATCH_QUEUE_SERIAL);
//It works without Warning message.
_centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:_centralQueue];

//用nil的話，預設是給它main queue
//_centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];

_receivedData = [[NSMutableData alloc] init];
//self.activePeripheral = [CBPeripheral new];
self.peripherals = [NSMutableArray new];

}

return self;

}

實作一個拍照的UIActionSheet

#pragma mark - Image capture

- (IBAction)takePicture:(UITapGestureRecognizer*)sender {

UIActionSheet *sheet;

sheet = [[UIActionSheet alloc] initWithTitle:@"Pick Photo"

delegate:self

  cancelButtonTitle:@"Cancel"

  destructiveButtonTitle:nil

  otherButtonTitles:@"Take Photo", @"Choose Photo", nil];

[sheet showInView:self.navigationController.view];

}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

[picker dismissViewControllerAnimated:YES completion:nil];

}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

[picker dismissViewControllerAnimated:YES completion:nil];

}

#pragma mark - UIActionSheet Delegate

- (void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex {

UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];

imagePicker.delegate = self;

switch (buttonIndex) {

case 0: {

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;

[self presentViewController:imagePicker animated:YES completion:nil];

}

}

break;

case 1: {

imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

[self presentViewController:imagePicker animated:YES completion:nil];

}

break;

default:

break;

}

}

BLE回連 in iOS7

NSUUID *uuid = [[NSUUID alloc]initWithUUIDString:savedUUID];//where savedUUID is the string version of the NSUUID you've saved somewhere

NSArray *peripherals = [_cbCentralManager retrievePeripheralsWithIdentifiers:@[uuid]];

for(CBPeripheral *periph in peripherals)
{
    [_cbCentralManager connectPeripheral:peripheral options:nil];
}

實驗：objective-C物件做為method的參數，應是copy，而不是直接傳指標

//程式碼如下

- (void)viewDidLoad

{

    [super viewDidLoad];

    int a = 2;

    NSArray* b = @[@2];

    NSLog(@"before:a=%d b=%@",a,b);

    [self testInt:a Object:b];

    NSLog(@"after:a=%d b=%@",a,b);

}

-(void) testInt:(int)a Object:(NSArray*) b{

    a = 1;

    b = @[@1];

    NSLog(@"processing:a=%d b=%@",a,b);

}

//Log如下

2014-02-13 13:26:54.160 testParse[11196:70b] before:a=2 b=(

    2

)

2014-02-13 13:26:54.161 testParse[11196:70b] processing:a=1 b=(

    1

)

2014-02-13 13:26:54.163 testParse[11196:70b] after:a=2 b=(

    2

)