java - 黑莓应用程序显示空白屏幕

Question

大家好，我的黑莓应用程序遇到问题......................

我制作了一个简单的应用程序，它以一个名为 AppStarter 的文件启动

package in.EventTimer;

import net.rim.device.api.ui.UiApplication;

public class AppStarter extends UiApplication
{
    public static void main (String[] args)
    {
        AppStarter theApp = new AppStarter ();
        theApp.enterEventDispatcher ();
    }
    public AppStarter()
    {
        //display a new screen
        pushScreen (new ConnectionSettings ());
    }

}

从此 AppStarter 文件推送到第二个文件，该文件是 ConnectionSettings 的屏幕

package in.EventTimer;

import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.MainScreen;




public class ConnectionSettings extends MainScreen
{


    public void RadioButton()
    {

    RadioButtonGroup rbg = new RadioButtonGroup();
    RadioButtonField rb1 = new RadioButtonField("tcp");
    RadioButtonField rb2 = new RadioButtonField("gprs");
    RadioButtonField rb3 = new RadioButtonField("wifi");

    rbg.add(rb1);
    rbg.add(rb2);
    rbg.add(rb3);

    }





    public boolean onClose()
    {
        Dialog.alert ("Exit Connection Settings!");
        System.exit (0);
        return true;
    }

}

但是当我在我的 Blackberry 9700 模拟器中运行此应用程序时，它只是给出空白的白色屏幕，当我退出该白色屏幕时，它会给出消息 exitconnection settings 这意味着它位于连接设置屏幕上，但当我运行它时显示空白屏幕......我已经尝试了很多方法，但还没有解决方案......所以请帮助或建议一些东西。

提前致谢

Answer 1

尝试将以下方法添加到 ConnectionSettings 类:

public ConnectionSettings()
{
        super();

        LabelField title = new LabelField("HelloWorld Sample",
                LabelField.ELLIPSIS | LabelField.USE_ALL_WIDTH);
        setTitle(title);
        add(new RichTextField("Hello World!"));
}

看起来您缺少一个构造函数...对于您的 MainScreen 类

所以最终的代码应该是这样的:

package in.EventTimer;

import net.rim.device.api.ui.component.*; 
import net.rim.device.api.ui.container.MainScreen;

public class ConnectionSettings extends MainScreen {

    public void RadioButton()
    {

            RadioButtonGroup rbg = new RadioButtonGroup();
            RadioButtonField rb1 = new RadioButtonField("tcp");
            RadioButtonField rb2 = new RadioButtonField("gprs");
            RadioButtonField rb3 = new RadioButtonField("wifi");

            rbg.add(rb1);
            rbg.add(rb2);
            rbg.add(rb3);

            add(rb1);  //Added by eSniff
            add(rb2);  //Added by eSniff
            add(rb3);  //Added by eSniff

    }

    //Begin added by eSniff
    public ConnectionSettings() 
    {
        super();

        LabelField title = new LabelField("APP STARTER",
            LabelField.ELLIPSIS | LabelField.USE_ALL_WIDTH);
        setTitle(title);
        add(new RichTextField("Hello World!"));

        RadioButton();
    }
    //End added by eSniff


    public boolean onClose()
    {
        Dialog.alert ("Exit Connection Settings!");
        System.exit (0);
        return true;
    }
}