Summary of some small technologies in iPhone Development

Reference of the random number header file # import time. h # import Mach/mach_time.h srandom () Use srandom (unsigned) (mach_absolute_time () 0 xffffffff); Use random () to call Random Number 2 rotate the image in uiimageview
1. Use of random numbers

Header file reference
# Import <time. h>
# Import <Mach/mach_time.h>

Use of srandom ()
Srandom (unsigned) (mach_absolute_time () & 0 xffffffff ));

Directly use random () to call random numbers

2. Rotate the image in uiimageview

Float rotateangle = m_pi;
Cgaffinetransform transform = cgaffinetransformmakerotation (rotateangle );
Imageview. Transform = transform;

The above code rotates the imageview, and the angle is rotateangle. You can test the direction yourself!

3. How to set the rotation point in quartz

Uiimageview * imageview = [[uiimageview alloc] initwithimage: [uiimage imagenamed: @ "bg.png"];
Imageview. layer. anchorpoint = cgpointmake (0.5, 1.0 );

Set the rotation point to the center of the bottom. Remember that it is only supported in quartzcore. framework.

4. create and store the. plist File

Nsstring * errordesc; // used to store error messages
Nsmutabledictionary * rootobj = [nsmutabledictionary dictionarywithcapacity: 4]; // nsdictionary, nsdata, and other files can be directly converted to plist files.
Nsdictionary * innerdict;
Nsstring * Name;
Player * player;
Nsinteger saveindex;

For (INT I = 0; I <[playerarray count]; I ++ ){
Player = nil;
Player = [playerarray objectatindex: I];
If (player = nil)
Break;
Name = player. playername; // This "player1" denotes the player name cocould also be the computer name
Innerdict = [self getallnodeinfotodictionary: Player];
[Rootobj setobject: innerdict forkey: Name]; // This "player1" denotes the person who start this game
}
Player = nil;
Nsdata * plistdata = [nspropertylistserialization datafrompropertylist :( ID) rootobj format: nspropertylistxmlformat_v1_0 errordescription: & errordesc];

The red part can be ignored, just adding a bit of content to the rootobj. This plistdata is a created plist file, which can be written as a file using its writetofile method. The following code is used:

/* Get the file storage location on the mobile device */
Nsstring * documentspath = [self getdocumentsdirectory];
Nsstring * savepath = [documentspath stringbyappendingpathcomponent: @ "Save. plist"];

/* Save the file */
If (plistdata ){
[Plistdata writetofile: savepath atomically: Yes];
}
Else {
Nslog (errordesc );
[Errordesc release];
}

-(Nsstring *) getdocumentsdirectory {
Nsarray * paths = nssearchpathfordirectoriesindomains (nsdocumentdirectory, nsuserdomainmask, yes );
Return [paths objectatindex: 0];
}

4. Read the plist file and convert it to nsdictionary.

Nsstring * documentspath = [self getdocumentsdirectory];
Nsstring * fullpath = [documentspath stringbyappendingpathcomponent: @ "Save. plist"];
Nsmutabledictionary * plistdict = [[nsmutabledictionary alloc] initwithcontentsoffile: fullpath];

5. Read general document files

Nsstring * TMP;
Nsarray * lines;/* convert a file to a row */
Lines = [[nsstring stringwithcontentsoffile: @ "testfilereadlines.txt"]
Componentsseparatedbystring: @ "/N"];

Nsenumerator * neuron = [Lines objectenumerator];

// Read the content in <>
While (TMP = [neuron nextobject]) {
Nsstring * stringbetweenbrackets = nil;
Ns‑* token = [ns‑scannerwithstring: TMP];
[Export scanuptostring: @ "<" Export string: Nil];
[Export scanstring: @ "<" Export string: Nil];
[Export scanuptostring: @ ">" Export string: & stringbetweenbrackets];

Nslog ([stringbetweenbrackets description]);
}

For reading and writing files, there are also supplements. It is now. Random Numbers and file reads and writes are often used in game development. So I put some content here to share with you and record it for ease of searching.

6 hide navigationbar
[Self. navigationcontroller setnavigationbarhidden: Yes animated: Yes];

You can use it in the viewcontroller you want to hide.