IOS開發/iphone開發多線程

有時候可能有很多功能要同時實作，例如每隔多長時間就會檢測程式網絡連接配接，又或者有時候需要從伺服器下載下傳一個不小的檔案，如果用單線程幾乎是不可想的事情，程式将會卡的無法使用，用到多線程和不用多線程，給使用者的體驗天壤之别，是以多線程是一個ios開發人員必須學會的一個知識點。

多線程，聽得有點高深，其實很簡單。在iphone中，多線程可以這麼了解，除主線程外還有其他線程，主線程和其他線程的差別是最重要的，最簡單的了解方法就是主線程會改變界面，其他線程不會改變，主線程可以調用其他線程，

1.聲明一個線程又兩種方法：1.thread1=[[nsthread alloc]initwithtarget:self selector:@selector(tt1) object:nil];這種方法必須啟動 [thread1 start];

                                  2.[nsthread detachnewthreadselector:@selector(tt1) totarget:self withobject:nil];這種方法不需要聲明nsthread對象，也不需要啟動，預設執行到這句就直接運作了

2.當程式在背景執行時，可能有時候需要調用另外的方法，這個方法名是［self performselectorinbackground:@selector(threadmethod) withobject:nil］

3.設定線程優先級-(void)setthreadpriority:(double)priority;線程優先級是從0.0到1.0，1.0是最高優先級。系統預設的優先級是0.5

4.線程休眠：+(void)sleepfortimeinterval:(nstimeinterval)time;time參數為休眠時間。

5.線程的互動：線程的運作過程中，可能需要與其他線程進行通信，如在主線程中修改界面等等，可以使用如下接口：-(void)performselectoronmainthread:(sel)selectoe   withobject:(id)arg  waituntildone:(bool)wait;

6.線程的同步和線程瑣，可以了解下

7.線程池，可以了解下

用多線程實作一個簡單的程

#import <uikit/uikit.h>

@interface toolbar_1viewcontroller : uiviewcontroller {

    uilabel * l1;

    uilabel * l2;

    uilabel * l3;

    uilabel * l4;

    uilabel * l5;

    uibutton *b1;

    uibutton *b2;

    uibutton *b3;

    uibutton *b4;

    uibutton *b5;

    nsthread *thread1;

    nsthread *thread2;

    nsthread *thread3;

    nsthread *thread4;

    bool button1;

    bool button2;

    bool button3;

    bool button4;

    bool button5;

    int i1;

    int i2;

    int i3;

    int i4;

    int i5;

    nscondition *lock;

}

@property (nonatomic,retain)iboutlet uilabel *l1;

@property (nonatomic,retain)iboutlet uilabel *l2;

@property (nonatomic,retain)iboutlet uilabel *l3;

@property (nonatomic,retain)iboutlet uilabel *l4;

@property (nonatomic,retain)iboutlet uilabel *l5;

@property (nonatomic,retain)iboutlet uibutton *b1;

@property (nonatomic,retain)iboutlet uibutton *b2;

@property (nonatomic,retain)iboutlet uibutton *b3;

@property (nonatomic,retain)iboutlet uibutton *b4;

@property (nonatomic,retain)iboutlet uibutton *b5;

-(ibaction)b1:(id)sender;

-(ibaction)b2:(id)sender;

-(ibaction)b3:(id)sender;

-(ibaction)b4:(id)sender;

-(ibaction)b5:(id)sender;

-(void)t1;

-(void)tt1;

-(void)t2;

-(void)tt2;

-(void)t3;

-(void)tt3;

-(void)t4;

-(void)tt4;

-(void)changeall;

@end

#import "toolbar_1viewcontroller.h"

@implementation toolbar_1viewcontroller

@synthesize l1;

@synthesize l2;

@synthesize l3;

@synthesize l4;

@synthesize l5;

@synthesize b1;

@synthesize b2;

@synthesize b3;

@synthesize b4;

@synthesize b5;

-(ibaction)b1:(id)sender

{

    thread1=[[nsthread alloc]initwithtarget:self selector:@selector(tt1) object:nil]; 

    button1=!button1;

    if(button1){

        [b1 settitle:@"停止1" forstate:uicontrolstatenormal] ;

        [self changeall];

        [thread1 start];

    }

    else {

        [b1 settitle:@"啟動1" forstate:uicontrolstatenormal] ;

        [thread1 cancel];

-(void)changeall

    if (button1&&button2&button3&button4) {

        [b5 settitle:@"停止全部" forstate:uicontrolstatenormal] ;

        button5=yes;

    if (!button1&&!button2&!button3&!button4) {

        [b5 settitle:@"啟動全部" forstate:uicontrolstatenormal] ;

        button5=no;

-(void)tt1

    while (button1) {

        [self performselectoronmainthread:@selector(t1) withobject:nil waituntildone:no];

        [nsthread sleepfortimeinterval:1.0];

    }   

-(void)t1

    l1.text=[nsstring stringwithformat:@"%d",++i1];

    [lock lock];

    i5 ++ ;

    [lock unlock];

    l5.text=[nsstring stringwithformat:@"%d",i5];

    [self.view setneedsdisplay];

-(ibaction)b2:(id)sender

    thread2=[[nsthread alloc]initwithtarget:self selector:@selector(tt2) object:nil]; 

    button2=!button2;

    if(button2){

        [b2 settitle:@"停止2" forstate:uicontrolstatenormal] ;

        [thread2 start];

        [b2 settitle:@"啟動2" forstate:uicontrolstatenormal] ;

        [thread2 cancel];

-(void)tt2

    while (button2) {

        [self performselectoronmainthread:@selector(t2) withobject:nil waituntildone:no];

-(void)t2

    l2.text=[nsstring stringwithformat:@"%d",++i2];

-(ibaction)b3:(id)sender

    thread3=[[nsthread alloc]initwithtarget:self selector:@selector(tt3) object:nil];

    button3=!button3;

    if(button3){

        [b3 settitle:@"停止3" forstate:uicontrolstatenormal] ;

        [thread3 start];

        [b3 settitle:@"啟動3" forstate:uicontrolstatenormal] ;

        [thread3 cancel];

-(void)tt3

    while (button3) {

        [self performselectoronmainthread:@selector(t3) withobject:nil waituntildone:no];

-(void)t3

    l3.text=[nsstring stringwithformat:@"%d",++i3];

-(ibaction)b4:(id)sender

    thread4=[[nsthread alloc]initwithtarget:self selector:@selector(tt4) object:nil];

    button4=!button4;

    if(button4){

        [b4 settitle:@"停止4" forstate:uicontrolstatenormal] ;

        [thread4 start];

        [b4 settitle:@"啟動4" forstate:uicontrolstatenormal] ;

        [thread4 cancel];

-(void)tt4

    while (button4) {

        [self performselectoronmainthread:@selector(t4) withobject:nil waituntildone:no];

-(void)t4

    l4.text=[nsstring stringwithformat:@"%d",++i4];

-(ibaction)b5:(id)sender

    if(!button5){

        if (!button1) {

            thread1=[[nsthread alloc]initwithtarget:self selector:@selector(tt1) object:nil]; 

            button1=!button1;

            [b1 settitle:@"停止1" forstate:uicontrolstatenormal] ;

            [thread1 start];

        }

        if (!button2) {

            thread2=[[nsthread alloc]initwithtarget:self selector:@selector(tt2) object:nil]; 

            button2=!button2;

            [b2 settitle:@"停止2" forstate:uicontrolstatenormal] ;

            [thread2 start];

        if (!button3) {

            thread3=[[nsthread alloc]initwithtarget:self selector:@selector(tt3) object:nil]; 

            button3=!button3;

            [b3 settitle:@"停止3" forstate:uicontrolstatenormal] ;

            [thread3 start];

        if (!button4) {

            thread4=[[nsthread alloc]initwithtarget:self selector:@selector(tt4) object:nil]; 

            button4=!button4;

            [b4 settitle:@"停止4" forstate:uicontrolstatenormal] ;

            [thread4 start];

    else{

        if (button1) {

            [b1 settitle:@"啟動1" forstate:uicontrolstatenormal] ;

            [thread1 cancel];

        if (button2) {

            [b2 settitle:@"啟動2" forstate:uicontrolstatenormal] ;

            [thread2 cancel];

        if (button3) {

            [b3 settitle:@"啟動3" forstate:uicontrolstatenormal] ;

            [thread3 cancel];

        if (button4) {

            [b4 settitle:@"啟動4" forstate:uicontrolstatenormal] ;

            [thread4 cancel];

        }       

    button5=!button5;

- (void)dealloc

    [l1 release];

    [l2 release];

    [l3 release];

    [l4 release];

    [l5 release];

    [b1 release];

    [b2 release];

    [b3 release];

    [b4 release];

    [b5 release];

    [thread1 release];

    [thread2 release];

    [thread3 release];

    [thread4 release];

    [super dealloc];

- (void)viewdidload

    i1=0;

    button1=false;

    button2=false;

    button3=false;

    button4=false;

    button5=false;

    i5=i2=i3=i4=i1;

    l1.text=[nsstring stringwithformat:@"%d",i1];

    l2.text=[nsstring stringwithformat:@"%d",i2];

    l3.text=[nsstring stringwithformat:@"%d",i3];

    l4.text=[nsstring stringwithformat:@"%d",i4];

xib檔案如下