IOS 自带地图应用_路径导航

//

//  ViewController.m

//  NSThread

//

//  Created by dc008 on 15/12/24.

//  Copyright © 2015年 崔晓宇. All rights reserved.

//

#import "ViewController.h"

@interface ViewController ()

{    //用于显示下载的图片

    UIImageView *_imageView;

}

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    [self layout];

}

- (void)layout{

    

    _imageView = [[UIImageView alloc]initWithFrame:[UIScreen mainScreen].bounds];

    _imageView.contentMode = UIViewContentModeScaleAspectFill;

    [self.view addSubview:_imageView];

    

    //下载按钮

    UIButton *button = [[UIButton alloc]initWithFrame:CGRectMake(120, 420, 80, 20)];

    [button setTitle:@"加载图片" forState:UIControlStateNormal];

    [button addTarget:self action:@selector(loadImageWithMultiThread) forControlEvents:UIControlEventTouchUpInside];

    [button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];

    [button setTitleColor:[UIColor grayColor] forState:UIControlStateHighlighted];

    [self.view addSubview:button];

}

- (void)noNSThread{

    //在资源下载加载的过程当中，因为网络缘由，有时候咱们是很难保证下载时间的，若是不使用多线程可能用户完成一个下载操做须要很长时间的等待，并且在这个过程当中没法进行其余操做-》阻塞。

    UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://img2.3lian.com/2014/f7/5/d/22.jpg"]]];

    _imageView.image = image;

}

#pragma mark 多线程下载图片

- (void)loadImageWithMultiThread{

    //方法1:使用对象方法

    //建立一个线程

    NSThread *thread1 = [[NSThread alloc]initWithTarget:self selector:@selector(loadImage) object:nil];

    [thread1 start];//启动一个线程,并不表明当即执行,而是处于就绪状态,当系统调度时才真正执行

    

    //方法2.使用类方法

//    [NSThread detachNewThreadSelector:@selector(loadImage) toTarget:self withObject:nil];

}

- (void)loadImage{

    //请求图片数据

    NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://img2.3lian.com/2014/f7/5/d/22.jpg"]];

    //注意只能在主线程中更新UI

    //performSelectorOnMainThread 这个方法是NSObject的分类方法,每一个NSObject对象都有这个方法

    [self performSelectorOnMainThread:@selector(updataImageView:) withObject:data waitUntilDone:YES];

}

- (void)updataImageView : (NSData *)imageData{

    UIImage *image = [UIImage imageWithData:imageData];

    _imageView.image = image;

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end