as 3.0图片上传预览本地图片

需要Flash Player 10+版本的支持，原理就是主要利用fp10中的FileReference.load()，FileReference.data和 Loader.loadBytes()三个方法通过图片加载到内存中，来实现预览本地图片，但这个方式不太适用大图片预览，图片越大内存消耗就越大。

[注意]：

1.我这边图片上传路径是无效的，所以图片上传失败是正常的，你们可以改一下上传路径即可；

2.需要Flash Player 10的支持；

3.这次主要研究是预览本地图片功能。

演示效果：

实现代码：

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package project.test
{
    import flash.display.*;
    import flash.geom.Rectangle;
    import flash.net.*;
    import flash.text.*;
    import flash.filters.*;
    import flash.events.*;
    import flash.system.Security;

    import fl.controls.Button;
    import fl.controls.ProgressBar;
    import fl.controls.ProgressBarMode;

    /**
     * @link kinglong@gmail.com
     * @author Kinglong
     * @playerversion fp10
     */
    [SWF(width="500", height="300", frameRate="24", backgroundColor="#FFFFFF")]
    public class TestUpload extends Sprite {

        private const DEFAULT_UPLOAD_PAGE:String = "http://test.klstudio.com/upload.asp";
        private const BOX_WIDTH:uint = 500;
        private const BOX_HEIGHT:uint = 300;

        private const STATE_CACHE:String = "cache";
        private const STATE_UPLOAD:String = "upload";

        private var _filters:Array;
        private var _file:FileReference;
        private var _loader:Loader;
        private var _progress:ProgressBar;
        private var _state:String;
        private var _buttons:Array;
        private var _labels:Array;
        private var _txts:Array;
        private var _rect:Rectangle;
        private var _state_txt:TextField;

        public function TestUpload() {
            Security.allowDomain("*");

            _buttons = [];
            _txts = [];
            _labels = ["文件名称:","文件类型:","文件大小:","修改时间:"];

            _rect = new Rectangle(20, 80, 180, 180);
            _state = STATE_CACHE;

            //背景;
            this.graphics.beginFill(0x333333);
            this.graphics.drawRoundRect(0, 0, BOX_WIDTH, BOX_HEIGHT, 10, 10);
            this.graphics.endFill();
            this.graphics.beginFill(0xEFEFEF);
            this.graphics.drawRoundRect(1, 1, BOX_WIDTH - 2, BOX_HEIGHT - 2, 10, 10);
            this.graphics.endFill();
            this.graphics.beginFill(0x666666);
            this.graphics.drawRoundRect(10, 30, BOX_WIDTH - 20, BOX_HEIGHT - 60, 20, 20);
            this.graphics.endFill();
            this.graphics.beginFill(0xFEFEFE);
            this.graphics.drawRoundRect(11, 31, BOX_WIDTH - 22, BOX_HEIGHT - 62, 20, 20);
            this.graphics.endFill();

            this.graphics.beginFill(0xCCCCCC);
            this.graphics.drawRect(11, 70, BOX_WIDTH - 22, 1);
            this.graphics.endFill();

            this.graphics.beginFill(0x000000);
            this.graphics.drawRect(_rect.x-1, _rect.y-1, _rect.width+2, _rect.height+2);
            this.graphics.endFill();
            this.graphics.beginFill(0xEEEEEE);
            this.graphics.drawRect(_rect.x, _rect.y, _rect.width, _rect.height);
            this.graphics.endFill();


            //标题;
            var label:TextField;
            label = getLabel("图片上传（预览图片版） by Kinglong", getTextFormat(0xFFFFFF, 14, true));
            label.x = 10;
            label.y = 5;
            label.filters = [getLabelFilter(0x000000)];
            this.addChild(label);

            for (var i:uint = 0; i < _labels.length; i++ ) {
                label = getLabel(_labels[i], getTextFormat(0x333333, 12), false, false);
                label.x = _rect.right+5;
                label.y = _rect.y + 25 * i;
                label.width = 280;
                label.height = 20;
                _txts.push(label);
                this.addChild(label);
            }

            _state_txt = getLabel("状态:", getTextFormat(0x333333, 12));
            _state_txt.x = 10;
            _state_txt.y = BOX_HEIGHT - _state_txt.height - 5;
            this.addChild(_state_txt);

            //按钮;
            var button:Button;
            button = getButton("选择文件", 80);
            button.move(20, 40);

            button = getButton("上传文件", 80);
            button.move(105, 40);
            button.enabled = false;

            //进度条;
            _progress = new ProgressBar();
            _progress.move(190, 40);
            _progress.setSize(290,22);
            _progress.mode = ProgressBarMode.MANUAL;
            this.addChild(_progress);

            //文件类型;
            _filters = [];
            var filter:FileFilter;
            filter = new FileFilter("所有支持图片文件(*.jpg,*.jpeg,*.gif,*.png)", "*.jpg;*.jpeg;*.gif;*.png");
            _filters[_filters.length] = filter;
            filter = new FileFilter("JPEG files(*.jpg,*.jpeg)","*.jpg;*.jpeg");
            _filters[_filters.length] = filter;
            filter = new FileFilter("GIF files (*.gif)","*.gif");
            _filters[_filters.length] = filter;
            filter = new FileFilter("PNG files(*.png)","*.png");
            _filters[_filters.length] = filter;

            _file = new FileReference();
            _file.addEventListener(Event.COMPLETE, fileHandler);
            _file.addEventListener(DataEvent.UPLOAD_COMPLETE_DATA, fileHandler);
            _file.addEventListener(Event.SELECT, fileHandler);
            _file.addEventListener(Event.OPEN, fileHandler);
            _file.addEventListener(ProgressEvent.PROGRESS, fileHandler);
            _file.addEventListener(SecurityErrorEvent.SECURITY_ERROR, fileHandler);
            _file.addEventListener(IOErrorEvent.IO_ERROR, fileHandler);
            _file.addEventListener(HTTPStatusEvent.HTTP_STATUS, fileHandler);

            _loader = new Loader();
            _loader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadHandler);
            this.addChild(_loader);
        }

        public function get state():String {
            return _state;
        }

        private function clickHandler(event:MouseEvent):void {
            switch(event.target) {
                case _buttons[0]:
                    _file.browse(_filters);
                    break;
                case _buttons[1]:
                    _file.upload(new URLRequest(DEFAULT_UPLOAD_PAGE));
                    _state = STATE_UPLOAD;
                    _buttons[0].enabled = false;
                    _buttons[1].enabled = false;
                    break;
            }
        }

        private function loadHandler(event:Event):void {
            _loader.scaleX = _loader.scaleY = 1;
            var w:uint = _loader.width;   www.226500.cn/flash_a/flash.html
            var h:uint = _loader.height;
            if (w > _rect.width || h > _rect.height) {
                var ip:Number = w / h;
                var lp:Number = _rect.width / _rect.height;
                _loader.width = (ip > lp)?_rect.width:_rect.height*ip;
                _loader.height = (ip > lp)?_rect.width / ip:_rect.height;
            }
            _loader.x = _rect.x + (_rect.width - _loader.width) / 2;
            _loader.y = _rect.y + (_rect.height - _loader.height) / 2;
            _loader.visible = true;
        }

        private function fileHandler(event:Event):void {
            switch(event.type) {
                case Event.COMPLETE:
                    if(state == STATE_CACHE){
                        _loader.loadBytes(_file.data);
                    }
                    break;
                case DataEvent.UPLOAD_COMPLETE_DATA:
                    debug("图片上传完成!");
                    _buttons[0].enabled = true;
                    _buttons[1].enabled = false;
                    _progress.setProgress(0, 1);
                    break;
                case Event.SELECT:
                    _txts[0].text = _labels[0] + _file.name;
                    _txts[1].text = _labels[1] + _file.type;
                    _txts[2].text = _labels[2] + ((_file.size > 1024 * 1024)?Math.round(_file.size * 10 / (1024*1024))/10
+ "MB":Math.round(_file.size * 10 / 1024)/10 + "KB");
                    _txts[3].text = _labels[3] + date2str(_file.modificationDate);
                    _buttons[0].enabled = true;
                    _buttons[1].enabled = true;
                    _file.load();
                    _state = STATE_CACHE;
                    _loader.visible = false;
                    debug("图片已经准备!");
                    break;
                case Event.OPEN:
                    if(state == STATE_UPLOAD){
                        debug("正在上传图片...");
                    }
                    break;
                case ProgressEvent.PROGRESS:
                    if (state == STATE_UPLOAD) {
                        var pEvent:ProgressEvent = event as ProgressEvent;
                        _progress.setProgress(pEvent.bytesLoaded, pEvent.bytesTotal);
                    }
                    break;
                case SecurityErrorEvent.SECURITY_ERROR:
                case IOErrorEvent.IO_ERROR:
                case HTTPStatusEvent.HTTP_STATUS:
                    if (state == STATE_UPLOAD) {
                        debug("图片上传失败!");
                        _buttons[0].enabled = true;
                        _buttons[1].enabled = true;
                    }else {
                        debug("图片缓冲失败!");
                    }
                    _progress.setProgress(0, 1);
                    break;

            }
        }

        private function getButton(lbl:String,width:uint=120):Button {
            var button:Button = new Button();
            button.label = lbl;
            button.setSize(width, 22);
            button.setStyle("textFormat", getTextFormat());
            button.setStyle("disabledTextFormat", getTextFormat(0x999999));
            button.setStyle("textPadding",4);
            button.addEventListener(MouseEvent.CLICK, clickHandler);
            this.addChild(button);
            _buttons.push(button);
            return button;
        }

        private function getLabel(label:String, format:TextFormat, selectable:
Boolean = false, autoSize:Boolean = true):TextField {
            var lbl:TextField = new TextField();
            lbl.selectable = selectable;
            lbl.defaultTextFormat = format;
            if(autoSize){
                lbl.autoSize = TextFieldAutoSize.LEFT;
            }
            lbl.text = label;
            return lbl;
        }

        private function getTextFormat(color:uint=0x000000,size:uint = 12,bold:Boolean=false):
TextFormat {
            var format:TextFormat = new TextFormat();
            format.font = "宋体";
            format.color = color;
            format.size = size;
            format.bold = bold;
            return format;
        }

        private function getLabelFilter(color:uint=0xFFFFFF):BitmapFilter {
            var alpha:Number = 0.8;
            var blurX:Number = 2;
            var blurY:Number = 2;
            var strength:Number = 3;
            var inner:Boolean = false;
            var knockout:Boolean = false;
            var quality:Number = BitmapFilterQuality.HIGH;

            return new GlowFilter(color,
                                  alpha,
                                  blurX,
                                  blurY,
                                  strength,
                                  quality,
                                  inner,
                                  knockout);
        }

        private function date2str(day:Date):String {
            var str:String = day.getFullYear() + "-";
            str += num2str(day.getMonth() + 1) + "-";
            str += num2str(day.getDate()) + " ";
            str += num2str(day.getHours()) + ":";
            str += num2str(day.getMinutes()) + ":";
            str += num2str(day.getSeconds());
            return str;
        }

        private function num2str(val:Number):String {
            var str:String = "00" + val;
            return str.substr(str.length - 2, 2);
        }

        private function debug(message:String):void {
            _state_txt.text = message;
        }

    }

}

更多flash代码教程

www.226500.cn/flash_a/flash.html

补充：flash教程,As3.0