不知道各位对于这个需求要如何解决？
可能有些人会想到js与原生交互，js监听图片点击事件，然后将图片的url传递给原生App端，然后原生App将图片保存到相册，这样子麻烦吗？超麻烦。
（1）js监听图片长按事件；
（2）js将图片url传递给原生；
（3）原生通过图片的url生成UIImage；
（4）保存UIImage到系统相册;
步骤如下：
需要注入的js代码：
@"document.ontouchstart = function (event) {\
x = event.targetTouches[0].clientX;\
y = event.targetTouches[0].clientY;\
document.location = \"myweb:touch:start:\"+x+\":\"+y;};\
document.ontouchmove = function (event) {\
x = event.targetTouches[0].clientX;\
y = event.targetTouches[0].clientY;\
document.location = \"myweb:touch:move\"+x+\":\"+y;};\
document.ontouchcancel = function (event) {\
document.location = \"myweb:touch:cancel\";};\
document.ontouchend=function(event){\
document.location=\"myweb:touch:end\";};";
其中
touchstart，
touchmove，
touchend
用来捕获元素的触摸事件。
第一步：需要将js代码注入到交互的页面中。
-(void)webViewDidFinishLoad:(UIWebView *)webView {
[self.webView stringByEvaluatingJavaScriptFromString:kTouchJavaScriptString];
}
第二步：
用js来监听触摸图片长按事件，然后在webview的delegate方法里截取resquest就行了：
用到如下的代理方法：
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
然后，根据触摸点x,y的位置，并且通过js
document.elementFromPoint(%f, %f).tagName获取标签，
然后判断是不是图片，
如果是图片的话，提取图片的src
document.elementFromPoint(%f, %f).src
第三步：
将图片的URL经过转换成原生OC可以用的URL
// _imgURL<===>document.elementFromPoint(%f, %f).src
NSString *urlToSave = [self.webView stringByEvaluatingJavaScriptFromString:_imgURL];,
然后生成UIImage
第四步：保存UIImage到系统相册
掘金上面的另一种解决方案：
https://juejin.im/post/5981a278f265da3e260954b1
我自己如下的解决方案：
代码：
#import "ViewController.h"
#import <WebKit/WebKit.h>
#import "WKDelegateController.h"
typedef enum : NSUInteger {
GESTURE_STATE_START,
GESTURE_STATE_MOVE,
GESTURE_STATE_END,
} GESTURE_STATE;
@interface ViewController()<UIWebViewDelegate>
@property (nonatomic, strong) UIWebView *webView;
@property (nonatomic, strong) NSString *imgURL;
@property (nonatomic, strong) NSTimer *timer;
@property (nonatomic, assign) GESTURE_STATE gesState;
@end
static NSString * const kTouchJavaScriptString =
@"document.ontouchstart = function (event) {\
x = event.targetTouches[0].clientX;\
y = event.targetTouches[0].clientY;\
document.location = \"myweb:touch:start:\"+x+\":\"+y;};\
document.ontouchmove = function (event) {\
x = event.targetTouches[0].clientX;\
y = event.targetTouches[0].clientY;\
document.location = \"myweb:touch:move\"+x+\":\"+y;};\
document.ontouchcancel = function (event) {\
document.location = \"myweb:touch:cancel\";};\
document.ontouchend=function(event){\
document.location=\"myweb:touch:end\";};";
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.webView = [[UIWebView alloc] initWithFrame:self.view.bounds];
self.webView.delegate = self;
[self.view addSubview:self.webView];
NSString *urlStr = @"http://politics.people.com.cn/n1/2017/0810/c14562-29463365.html";
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlStr]];
[self.webView loadRequest:request];
}
-(void)webViewDidFinishLoad:(UIWebView *)webView {
[self.webView stringByEvaluatingJavaScriptFromString:kTouchJavaScriptString];
}
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSString *requestString = [[request URL] absoluteString];
NSLog(@"%s", __func__);
NSLog(@"requestString = %@", requestString);
NSLog(@"currentThread = %@", [NSThread currentThread]);
NSArray *components = [requestString componentsSeparatedByString:@":"];
if ([components count] > 1 && [(NSString *)[components objectAtIndex:0]
isEqualToString:@"myweb"]) {
if([(NSString *)[components objectAtIndex:1] isEqualToString:@"touch"]) {
if ([(NSString *)[components objectAtIndex:2] isEqualToString:@"start"]) {
_gesState = GESTURE_STATE_START;
NSLog(@"touch start!");
float ptX = [[components objectAtIndex:3] floatValue];
float ptY = [[components objectAtIndex:4] floatValue];
NSLog(@"touch point (%f, %f)", ptX, ptY);
NSString *js = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).tagName", ptX, ptY];
NSString *tagName = [self.webView stringByEvaluatingJavaScriptFromString:js];
_imgURL = nil;
if ([tagName isEqualToString:@"IMG"]) {
_imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", ptX, ptY];
}
if (_imgURL) {
_timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(handleLongTouch) userInfo:nil repeats:NO];
}
}
else if ([(NSString *)[components objectAtIndex:2] isEqualToString:@"move"]) {
//**如果touch动作是滑动，则取消hanleLongTouch动作**//
_gesState = GESTURE_STATE_MOVE;
NSLog(@"you are move");
} else if ([(NSString*)[components objectAtIndex:2]isEqualToString:@"end"]) {
[_timer invalidate];
_timer = nil;
_gesState = GESTURE_STATE_END;
NSLog(@"touch end");
}
}
return NO;
}
return YES;
}
- (void)handleLongTouch {
NSLog(@"%@", _imgURL);
if (_imgURL && _gesState == GESTURE_STATE_START) {
UIActionSheet* sheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"保存图片", nil];
sheet.cancelButtonIndex = sheet.numberOfButtons - 1;
[sheet showInView:[UIApplication sharedApplication].keyWindow];
}
}
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
if (actionSheet.numberOfButtons - 1 == buttonIndex) {
return;
}
NSString* title = [actionSheet buttonTitleAtIndex:buttonIndex];
if ([title isEqualToString:@"保存图片"]) {
if (_imgURL) {
NSLog(@"imgurl = %@", _imgURL);
}
NSString *urlToSave = [self.webView stringByEvaluatingJavaScriptFromString:_imgURL];
NSLog(@"image url=%@", urlToSave);
NSData* data = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlToSave]];
UIImage* image = [UIImage imageWithData:data];
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
}
- (void) dealloc {
if(self.webView){
[self.webView stopLoading];
self.webView.delegate = nil;
}
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo{
if (error){
NSLog(@"Error");
// [self showAlert:@"保存失败"];
}else {
NSLog(@"OK");
// [self showAlert:@"保存成功"];
}
}
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