黑莓视频与文本显示概率

Question

我需要一个视频屏幕，在视频播放下，我想显示两行文字，如下所示。

为此我使用以下代码。

public final class PlayVideoScreen extends MainScreen {
    private Player player;
    private VideoControl videoControl;

    public PlayVideoScreen() {

        // ms.setTitle(new LabelField("Let's play some video..."));
        LabelField lf = new LabelField("Video Play");

        try {
            // Create a new Player pointing to the video file.
            // This can use any valid URL.
            player = javax.microedition.media.Manager
                    .createPlayer("file:///SDCard/BlackBerry/videos/sample.avi");

            player.realize();

            // Create a new VideoControl.
            videoControl = (VideoControl) player.getControl("VideoControl");
            // Initialize the video mode using a Field.
            Field videoField = (Field) videoControl.initDisplayMode(
                    VideoControl.USE_GUI_PRIMITIVE,
                    "net.rim.device.api.ui.Field");

            add(videoField);

            VolumeControl volume = (VolumeControl) player
                    .getControl("VolumeControl");
            volume.setLevel(30);


            player.start();

            // Set the video control to be visible.
            // videoControl.setVisible(true);
        } catch (MediaException me) {
            Dialog.alert(me.toString());
        } catch (IOException ioe) {
            Dialog.alert(ioe.toString());
        }

        add(lf);

         LabelField lf2 = new LabelField("How r you?");

         add(lf2);
    }

    public boolean onClose() {
        // Clean up the player resources.
        player.close();
        videoControl.setVisible(false);
        close();
        return true;
    }
}

现在可能是视频的高度，视图正在滚动，文本只在滚动后才可见。我正在使用屏幕尺寸为320X240px的设备。我甚至测试了320X150px的视频。但是，如果没有滚动，文本是不可见的，尽管视频的上方和下方有很多可用空间。我的代码有什么问题？怎么解决？

Answer 1

有几种方法可以解决您的问题。最简单的方法是使用MainScreen#setStatus设置此屏幕状态部分的内容。

不是直接添加LabelField，而是按以下方式添加：

VerticalFieldManager vfm = new VerticalFieldManager();
vfm.add(lf);
vfm.add(lf2);
setStatus(vfm);

编辑：另一种解决方案是自行布局和定位子字段。为此，您可以覆盖PlayVideoScreen的sublayout()或引入其他管理员（VerticalFieldManager），向其添加所有字段（视频和标签）并覆盖其sublayout()方法。

以下是具有上述修改的代码

public PlayVideoScreen() {
    super(NO_VERTICAL_SCROLL);

    // ms.setTitle(new LabelField("Let's play some video..."));
    final LabelField lf = new LabelField("Video Play");

    try {
        // Create a new Player pointing to the video file.
        // This can use any valid URL.
        player = javax.microedition.media.Manager
                .createPlayer("file:///SDCard/BlackBerry/videos/sample.avi");

        player.realize();

        // Create a new VideoControl.
        videoControl = (VideoControl) player.getControl("VideoControl");
        // Initialize the video mode using a Field.
        final Field videoField = (Field) videoControl.initDisplayMode(
            VideoControl.USE_GUI_PRIMITIVE,
            "net.rim.device.api.ui.Field");

            VolumeControl volume = (VolumeControl) player
                    .getControl("VolumeControl");
        volume.setLevel(30);

        player.start();

        // Set the video control to be visible.
        // videoControl.setVisible(true);

        final LabelField lf2 = new LabelField("How r you?");

        VerticalFieldManager vfm = new VerticalFieldManager(NO_VERTICAL_SCROLL) {
            protected void sublayout(int maxWidth, int maxHeight) {
                int heightLeft = maxHeight;

                // layout the children fields
                layoutChild(lf, maxWidth, heightLeft);
                heightLeft -= lf.getHeight();

                layoutChild(lf2, maxWidth, heightLeft);
                heightLeft -= lf2.getHeight();

                layoutChild(videoField, maxWidth, heightLeft);

                // position the children fields
                int yPos = 0;
                setPositionChild(videoField, 0, yPos);
                yPos += videoField.getHeight();

                setPositionChild(lf, 0, yPos);
                yPos += lf.getHeight();

                setPositionChild(lf2, 0, yPos);

                setExtent(maxWidth, maxHeight);
            };
        };
        vfm.add(videoField);
        vfm.add(lf);
        vfm.add(lf2);

        add(vfm);

    } catch (MediaException me) {
        Dialog.alert(me.toString());
    } catch (IOException ioe) {
        Dialog.alert(ioe.toString());
    }
}