Apache flex 将按钮错误另存为项目

下面的代码有什么问题，上有一个错误 saveButton.visible=false； discardButton.visible=false

package
{
import flash.display.Sprite;
import flash.media.Camera;
import flash.media.Video;
import flash.display.BitmapData;
import flash.display.Bitmap;
import flash.events.MouseEvent;
import flash.net.FileReference;
import flash.utils.ByteArray;
import com.adobe.images.JPGEncoder;

public class caml extends Sprite
{
    private var camera:Camera = Camera.getCamera();
    private var video:Video = new Video();
    private var bmd:BitmapData = new BitmapData(320,240);
    private var bmp:Bitmap;
    private var fileReference:FileReference = new FileReference();
    private var byteArray:ByteArray;
    private var jpg:JPGEncoder = new JPGEncoder();

    public function caml()
    {
        saveButton.visible = false;
        discardButton.visible = false;

        saveButton.addEventListener(MouseEvent.MOUSE_UP, saveImage);
        discardButton.addEventListener(MouseEvent.MOUSE_UP, discard);
        capture.addEventListener(MouseEvent.MOUSE_UP, captureImage);

        if (camera != null)
        {
            video.smoothing = true;
            video.attachCamera(camera);
            video.x = 140;
            video.y = 40;
            addChild(video);
        }
        else
        {
            trace("No Camera Detected");
        }
    }
        private function captureImage(e:MouseEvent):void
        {
            bmd.draw(video);
            bmp = new Bitmap(bmd);
            bmp.x = 140;
            bmp.y = 40;
            addChild(bmp);

            capture.visible = false;
            saveButton.visible = true;
            discardButton.visible = true;
        }

        private function saveImage(e:MouseEvent):void
        {
            byteArray = jpg.encode(bmd);
            fileReference.save(byteArray, "Image.jpg");
            removeChild(bmp);
            saveButton.visible = false;
            discardButton.visible = false;
            capture.visible = true;
        }

        private function discard(e:MouseEvent):void
        {
            removeChild(bmp);
            saveButton.visible = false;
            discardButton.visible = false;
            capture.visible = true;
        }


}
}

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我猜这是一个文档根类，按钮被添加到flashfla文件的stage中。在这种情况下，您需要将按钮添加到您作为公共成员的声明中：

public var saveButton : Button;
public var discardButton : Button;

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更新

我本人从未使用过flash组件，但您可以在此处找到有关如何在Flashbuilder中使用flash组件的答案：

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从这段代码（如果不是部分代码）中可以看出，saveButton和discardButton在您到达的地方将为null。您没有初始化这些变量。我想到了同样的问题，以及如何将按钮附加到按钮事件，以及如何导入按钮；（请确保在编译之前将组件添加到您的阶段或资源库中，否则它将无法工作）。