Quartz introduction

drawRect:

drawRect method of UIVew is called when a view needs to redraw itself

we usually add drawing code in this function

install ipa

from cydia,

add source: http://cydia.hackulo.us.

install app: AppSync

restart ipod

ipa website:http://appulo.us/appdb/

thread & lock

- (void)performSelectorOnMainThread:(SEL)aSelector withObject:(id)arg waitUntilDone:(BOOL)wait;

create new thread to do something

- (void)performSelectorInBackground:(SEL)aSelector withObject:(id)arg;

sleep

[NSThread sleepForTimeInterval:0.5]

lock:

ex:

NSLock *testLock = [[NSLock alloc] init];

[testLock lock];

[testLock unlock];

[testLock release];

UILabel

adjust line number:

can adjust from interface builder

ipod touch 破解方法

1. download redsn0w-mac_0.8

2. run redsnow

3. choose iPod2,1_3.0_7A341_Restore.ipsw

4. plugin ipod , close ipod

5. let iphone enter DFU mode ( 按住home & 電源 10秒 ，接著按home for some time)

6. if the screen show "waiting for reboot", unplug ipod & plug ipod again

UIViewController

originally in view of A controller,

then show view of B controller:

[self presentModalViewController:testViewController animated:YES];

[testViewController release];

jump back to view of A controller

[self dismissModelViewControllerAnimated:YES];

UIButton

ex:

UIButton *backButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];

backButton.frame = CGRectMake(380, 260, 80, 30);

[backButton setTitle:@"Back" forState:UIControlStateNormal];

[backButton addTarget:self action:@selector(backButtonClicked:)

forControlEvents:UIControlEventTouchUpInside];