extjs上传图片预览与解决无法显示_Extjs上传图片预览与解决无法预览

在进行图片上传时，通常需要进行预览。而这种预览的行为通常是预览客户端的本地资源。下面就讲一下在Ext中是如何实现图片上传预览的。

      首先，创建为预览图片创建一个控件：

 

 代码如下 xtype : "box",
id : "logoPic",
width : 150,
height : 200,
autoEl : {
    tag : "img",
    src : currentLogoPath, 
    style : "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale);"
}

然后再创建一个图片上传的控件：

 代码如下 xtype : "textfield",
id : "logoFile",
name : "logoFile",
inputType : "file",
fieldLabel : "  商社标志文件",
width : 280,
listeners : {
 "render":function(){
  var logoFileCmp = Ext.get("logoFile");
  logoFileCmp.on("change",function(field,newValue,oldValue){
           var picPath = logoFileCmp.getValue();
           var url = "file:///" + picPath;
           if(Ext.isIE){
                                  var image = Ext.get("logoPic").dom; 
             image.src = Ext.BLANK_IMAGE_URL;
             image.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = url;
           }else{
             //支持FF
             Ext.get("logoPic").dom.src =Ext.get("logoFile").dom.files.item(0).getAsDataURL();
           }
         },this);
         }
}

为文件上传控件添加一个change事件。注意，在这里一定要用Ext.get方法取得控件，否则change事件会无效的。当有图片上传时，控件的值会发生改变，然后修改预览控件的src的值，以实现图片预览。

Extjs解决上传图片预览

网上找了好多EXTJS上传图片预览的，但都不行，，，下面虽然IE8可以但肯定还存在其它浏览器的兼容性问题，待搁应付一下吧。。

 代码如下

{
               width: 450,
               fileUpload: true,
               fieldLabel: "选择图片",
               items: [{
                   xtype: "textfield",
                   id: "up_forth",
                   name: "up_forth",
                   inputType: "file",
                   width: 300
               }]
}

预览box

{
                   columnWidth: .18,
                   bodyStyle: " margin:4px 10px 10px 5px",
                   layout: "form",
                   items: [{
                       xtype: "box",
                       autoEl: {
                           width: 150, height: 150,
                           tag: "div",
                           id: "browser_up_forth"
                       }
                   }]
}

 

myfrom表示上传控件外围的FormPanel,, contril_id表示上传控件的ID，只要在程序上预览注册该方法就可以，preview (myfrom,"up_forth" );

 代码如下

var preview = function (myform, control_id) {
    var img_reg = /.([jJ][pP][gG]){1}$|.([jJ][pP][eE][gG]){1}$|.([gG][iI][fF]){1}$|.([pP][nN][gG]){1}$|.([bB][mM][pP]){1}$/
    myform.on("render", function (f) {
        myform.form.findField(control_id).on("render", function () {
            Ext.get(control_id).on("change", function (field, newValue, oldValue) {
                var obj = Ext.get(control_id).dom;
                var url = getFullPath(obj);
                if (img_reg.test(url)) {
                    var newPreview = Ext.get("browser_" + control_id).dom;
                    var showPic = Ext.get("showPic_" + control_id);
                    if (showPic != null) {
                        showPic.remove();//删除原来的图片
                    }
                    var imgDiv = document.createElement("div");
                    imgDiv.id = "showPic_" + control_id;
                    document.body.appendChild(imgDiv);
                    imgDiv.style.width = "150px";
                    imgDiv.style.height = "150px";
                    imgDiv.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod = scale)";
                    imgDiv.filters.item("DXImageTransform.Microsoft.AlphaImageLoader").src = url;
                    newPreview.appendChild(imgDiv);
                }
            }, this);
        }, this);
    }, this);
}

//得到图片地址
function getFullPath(obj) {
    if (obj) {
        // ie
        if (window.navigator.userAgent.indexOf("MSIE") >= 1) {
            obj.select();
            return document.selection.createRange().text;
        }
        // firefox
        else if (window.navigator.userAgent.indexOf("Firefox") >= 1) {
            if (obj.files) {
                return obj.files.item(0).getAsDataURL();
            }
            return obj.value;
        }
        return obj.value;
    }
}

这样就解决了extjs上传图片无法正常预览的问题。

extjs上传图片预览与解决无法显示_Extjs上传图片预览与解决无法预览

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