-
[[UIScreen mainScreen] scale]： 计算屏幕分辨率
[[UIScreen main] scale] == 1; //代表320 x 480 的分辨率
[[UIScreen main] scale] == 2; //代表640 x 960 的分辨率。 4s
[[UIScreen main] scale] == 3; //代表1242 x 2208 的分辨率
2. 检测应用内是否安装某个应用
NSBundle *container = [NSBundle bundleWithPath:@"/System/Library/PrivateFrameworks/MobileContainerManager.framework"];
if ([container load]) {
Class appContainer = NSClassFromString(@"MCMAppContainer");
id test = [appContainer performSelector:@selector(containerWithIdentifier:error:) withObject:@"com.tencent.mqq11" withObject:nil];
NSLog(@"%@",test);
if (test) {
NSLog(@"yes");
} else {
NSLog(@"no");
}
}
或者用[[uiapplication shareapplication]openUrl:url];
3. 输入框显示输入长度
实现代理方法：
- (void)textViewDidChange:(UITextView *)textView{
NSString *toBeString = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
//获取高亮部分
UITextRange *selectedRange = [textView markedTextRange];
UITextPosition *position = [textView positionFromPosition:selectedRange.start offset:0];
// 没有高亮选择的字，则对已输入的文字进行字数统计和限制
if (!position)
{
if (toBeString.length > MAX_STARWORDS_LENGTH)
{
[MBProgressHUD showAlert:@"最多只能输入150个字。"];
NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];
if (rangeIndex.length == 1)
{
textView.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];
}
else
{
NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_STARWORDS_LENGTH)];
textView.text = [toBeString substringWithRange:rangeRange];
}
}
}
}
4.点击html中的图片，要求能够对该图片放大缩小
1》在webview的代理方法webViewDidFinishLoad中注入js
NSString *js = @"function addImgClickEvent() { \
var imgs = document.getElementsByTagName('img'); \
for (var i = 0; i < imgs.length; ++i) { \
var img = imgs[i]; \
img.onclick = function () { \
window.location.href = 'hyb-image-preview:' + this.src; \
}; \
} \
}";
// 注入JS代码
[webView stringByEvaluatingJavaScriptFromString:js];
// 执行所注入的JS代码
[webView stringByEvaluatingJavaScriptFromString:@"addImgClickEvent();"];
2》实现webview的代理方法
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSLog(@"request.URL:--------%@",request.URL);
if ([request.URL.scheme hasPrefix:@"hyb-image-preview"]) {
// 获取原始图片的完整URL
NSString *src = [request.URL.absoluteString stringByReplacingOccurrencesOfString:@"hyb-image-preview:" withString:@""];
if (src.length > 0) {
[self showImageWithPath:src];
//[self showImageWithURL:src];
}
}
return YES;
}
5.对webview进行缩放
_contentWebView.scalesPageToFit = YES;
_contentWebView.multipleTouchEnabled = YES;
_contentWebView.userInteractionEnabled = YES;
_contentWebView.scrollView.scrollEnabled = YES;
_contentWebView.contentMode = UIViewContentModeScaleAspectFit;
然后在webViewDidFinishLoad中注入js
NSString *jsMeta = [NSString stringWithFormat:@"var meta = document.createElement('meta');meta.content='width=device-width,initial-scale=1.0,minimum-scale=0.5,maximum-scale=3';meta.name='viewport';document.getElementsByTagName('head')[0].appendChild(meta);"];
[webView stringByEvaluatingJavaScriptFromString:jsMeta];