從URL獲取圖像到objective-c中的數組

Question

我想從頁面獲取圖像的所有URL的數組。

使用Javascript：

<script>
function newEl(tag){return document.createElement(tag);}

window.addEventListener('load', onDocLoaded, false);

function onDocLoaded()
{
    myAjaxRequest("http://foo.com/bar.html", onHtmlLoaded);
}

function onHtmlLoaded(ajax)
{
    var div = newEl('div');
    div.innerHTML = ajax.responseText;
    var imgs = div.getElementsByTagName('img');


    for (var i=7;i<imgs.length;i++)
    { 
    document.write("<p id='"+i+"'>"+imgs[i].src+"<p/>");
    }
}

function myAjaxRequest(url, callback)
{
    var ajax = new XMLHttpRequest();
    ajax.onreadystatechange = function()
    {
        if (this.readyState==4 && this.status==200)
            callback(this);
    }
    ajax.onerror = function()
    {
        console.log("AJAX request failed to: " + url);
    }
    ajax.open("GET", url, true);
    ajax.send();
}
</script>

我在這里所做的是通過一個如下所示的javascript獲取一個頁面（ www.foo.com/urls.html ），其中包含來自http://foo.com/bar.html的所有圖像URL：

HTML：

<p id="1">http://www.foo.com/x.jpg</p>
<p id="2">http://www.foo.com/y.jpg</p>
<p id="3">http://www.foo.com/z.jpg</p>
...

然后，我希望能夠在目標c中創建所有URL的數組，這可能嗎？

有沒有比這更好的方法了？

Answer 1

您應該將圖像URL存儲到數據庫中。

編寫腳本以獲取這些圖像，然后將其放入json數組

PHP

<?php
$mysqli = new mysqli("example.com", "user", "password", "database");
if ($mysqli->connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") ";
}

$res = $mysqli->query("SELECT image_name FROM images");


$data=array();
while ($row = $res->fetch_assoc()) {
    $data['images'][] = $row['image_name']; 
}

echo json_encode($data);
?>

然后從您的iOS應用程序請求JSON數據PHP腳本。

JSON：

{
    "images": [
        "http: //xxxxxxxxx.co.uk/video%20images/ONYX%20sofa.jpg",
        "http: //xxxxxxxxx.co.uk/video%20images/aaron%20duran.jpg",
        "http: //xxxxxxxxx.co.uk/video%20images/littledragon.jpg",
        "http: //xxxxxxxxx.co.uk/video%20images/cantalivering%20house.jpg"
    ]
}

最后，在您的應用中將其存儲到一個數組中。

IOS

NSURL *url = [NSURL URLWithString:@"http://www.url.com/get_images.php"];
//Creating the data object that will hold the content of the URL
NSData *jsonData = [NSData dataWithContentsOfURL:url];
NSError *error = nil;
//parse the JSON
NSDictionary *result = [NSJSONSerialization JSONObjectWithData:jsonData 
                              options:NSJSONReadingMutableContainers error:&error];
//Here is the array
NSArray *images = result[@"images"];
NSLog("images =%@", images);

Answer 2

雖然我不是100％地確定我了解您的問題以及您要完成的工作，但對我來說，這聽起來像是您在嘗試：

1. 運行您的JS代碼，並在HTML頁面中打印出您的URL
2. 在生成HTML頁面的URL列表的同時，您希望將這些相同的URL收集到數組中以供iOS項目中使用。

這可以通過iOS中的新JavaScriptCore框架來完成。 我必須說，這個答案的靈感來自於RayWenderlich.com的Tutorials在iOS 7中Pietro Rea 撰寫的關於JavaScriptCore的出色章節。 這是絕對必讀的東西。

為了提供您的解決方案（出於我們的目的，我假設您的數組在iOS視圖控制器中進行操作），您需要稍微重構JavaScript文件的代碼，以便您可以在同時構建HTML頁面。 此外，我將允許我的iOS視圖控制器控制何時發生這種情況，而不是在加載js / html文件時創建HTML頁面。

MyJavascriptFile.js ：（確保將此文件包含在iOS項目的“副本捆綁資源”部分中

<script>
function newEl(tag){return document.createElement(tag);}

//replace previous on load function call with function 
//that is called from Objective-C
function onObjectiveCLoaded() {
    myAjaxRequest("http://foo.com/bar.html", onHtmlLoaded);
}

function onHtmlLoaded(ajax) {
    var div = newEl('div');
    div.innerHTML = ajax.responseText;
    var imgs = div.getElementsByTagName('img');


    for (var i=7;i<imgs.length;i++) { 
        document.write("<p id='"+i+"'>"+imgs[i].src+"<p/>");

        //also, add our url to our objective-c array at same time            
        //this function is defined in MyViewController.m iOS file
        addURLToObjectiveCArray(imgs[i].src);
    }
}

function myAjaxRequest(url, callback) {
    var ajax = new XMLHttpRequest();
    ajax.onreadystatechange = function() {
        if (this.readyState==4 && this.status==200)
            callback(this);
    }
    ajax.onerror = function() {
        console.log("AJAX request failed to: " + url);
    }
    ajax.open("GET", url, true);
    ajax.send();
}
</script>

現在，在我們的iOS項目中：

頭文件：

//  MyViewController.h

#import <UIKit/UIKit.h>
#import <JavaScriptCore/JavaScriptCore.h>

@interface MyViewController : UIViewController
//this is required execution environment to run JS code locally
@property (strong, nonatomic) JSContext *jsContext;
@end

實施文件：

//  MyViewController.m

#import "MyViewController.h"

@interface MyViewController ()
@property (strong, nonatomic) NSMutableArray *myArrayOfURLs;
@end

@implementation MyViewController
- (void)viewDidLoad {
    [super viewDidLoad];

    //init our array
    self.myArrayOfURLs = [NSMutableArray new];

    //get a path to the javascript file we included in our bundle
    NSString *javascriptPath = [[NSBundle mainBundle] pathForResource:@"MyJavascriptFileName" ofType:@"js"];

    //turn our entire JS file into single string which we'll execute in our JS context
    NSError *error = nil;
    NSString *javascriptString = [NSString stringWithContentsOfFile:javascriptPath encoding:NSUTF8StringEncoding error:&error];

    if (error) {
        NSLog(@"Oops. Something happened.");
        return;
    }

    //init our context and evaluate our string of javascript
    self.jsContext = [[JSContext alloc] init];
    [self.jsContext evaluateScript:javascriptString];

    //grab a weak reference to self so we don't create strong retain cycle
    //within the block callback we're about to create
    __weak MyViewController *wSelf = self;

    //define the method/function we're calling from our JS file to add url to array
    //as we're creating our HTML page in our JS file, our JS file will call this
    //addURLToObjectiveCArray callback, passing in the current URL so we can add it
    self.jsContext[@"addURLToObjectiveCArray"] = ^(NSString *url) {
        [wSelf.myArrayOfURLs addObject:url];
    };

    //to ensure we don't prematurely create our url list in the JS file only,
    //only call that part of your JS file code from a function call here via
    //our context
    JSValue *jsFunction = self.jsContext[@"onObjectiveCLoaded"];
    [jsFunction callWithArguments:@[]];
}
@end

不要忘記將JavaScriptCore框架導入到您的iOS項目中！ 雖然我目前無法測試此解決方案，但肯定足以讓您入門。 再次強調一下， raywenderlich.com教程在這個主題上有多出色，因此請查看此處的所有內容的完整說明。