屏幕切换

[advancedprogramor]

我的应用想实现这样一个功能，就是先在一个屏幕上停留停留若干时间，然后自动切换到主屏幕，我是这样实现的

有两个屏幕类AppMainScreen,AppTempScreen,然后先pushScreen(AppTempScreen),接下来延时若干，再则pushScreen(AppMainScreen),最后就是进入事件分配，enterEventDispatcher()，其代码如下：

   public class AppManager extends UiApplication{
    public static void main(String[] args){
        AppManager AppManagerInstance =new AppManager();
                     AppManagerInstance.enterEventDispatcher();
        }
    AppManager() {
        AppTempScreen MyTempScreen=new AppTempScreen();
        this.pushScreen(MyTempScreen);
        this.delay(100000000);
        this.popScreen(MyTempScreen);
        this.pushScreen(new AppMainScreen());
        }
    private void delay(long sec){
        int i=0;
        while(i<sec)i++;
        }
} 
   

但是发现这样并不能实现预期功能，结构是，进入程序后，延迟一段时间后显示AppMainScreen定义的屏幕，而不显示 AppTempScreen定义的屏幕。

我认为的原因是，当pushScreen以后，会有一个消息进入消息队列，此消息要得到处理，必须是进入消息分配以后，也就是enterEventDispatcher后，也就是说在delay(100000000)调用前，屏幕显示并没有的到处理，后来又有popScreen的推送消息，还有this.pushScreen(new AppMainScreen());的消息，也就是说，在进入消息分配之前，消息队列中有三个消息，但为什么只处理 this.pushScreen(new AppMainScreen());的消息呢？我不得其解。

寻帮助。

[vercity]

用timer实现

push第二个screen可以写在第一个screen的实现中

[zyl0462]

private void delay(long sec){
int i=0;
while(i<sec)i++;
}
this.delay(100000000);
主要是这里的问题，这里计算很快的，基本上算是看不见，可以通过Timer和TimerTask来实现

[lixin1020]

UiApplication.getApplication().invokeLater
指定时间

[liusha0225]

黑莓里有屏幕切换的例子。


import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.FieldChangeListener;
import net.rim.device.api.ui.Screen;
import net.rim.device.api.ui.TransitionContext;
import net.rim.device.api.ui.Ui;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.UiEngineInstance;
import net.rim.device.api.ui.component.ButtonField;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.container.FullScreen;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.decor.BackgroundFactory;

public class ScreenTransitionSample extends UiApplication implements
FieldChangeListener {
private Screen _secondaryScreen;
private Runnable _popRunnable;

public static void main(String[] args) {
ScreenTransitionSample theApp = new ScreenTransitionSample();
theApp.enterEventDispatcher();
}

public ScreenTransitionSample() {
_secondaryScreen = new FullScreen();
_secondaryScreen.setBackground(BackgroundFactory
.createSolidBackground(Color.LIGHTBLUE));
LabelField labelField = new LabelField(
"The screen closes automatically in two seconds by using a fade transition");
_secondaryScreen.add(labelField);
TransitionContext transition = new TransitionContext(
TransitionContext.TRANSITION_SLIDE);
transition.setIntAttribute(TransitionContext.ATTR_DURATION, 500);
transition.setIntAttribute(TransitionContext.ATTR_DIRECTION,
TransitionContext.DIRECTION_RIGHT);
transition.setIntAttribute(TransitionContext.ATTR_STYLE,
TransitionContext.STYLE_PUSH);
UiEngineInstance engine = Ui.getUiEngineInstance();
engine.setTransition(null, _secondaryScreen,
UiEngineInstance.TRIGGER_PUSH, transition);
transition = new TransitionContext(TransitionContext.TRANSITION_FADE);
transition.setIntAttribute(TransitionContext.ATTR_DURATION, 500);
transition.setIntAttribute(TransitionContext.ATTR_KIND,
TransitionContext.KIND_OUT);
engine.setTransition(_secondaryScreen, null,
UiEngineInstance.TRIGGER_POP, transition);
MainScreen baseScreen = new MainScreen();
baseScreen.setTitle("Screen Transition Sample");
ButtonField buttonField = new ButtonField("View Transition",
ButtonField.CONSUME_CLICK);
buttonField.setChangeListener(this);
baseScreen.add(buttonField);
pushScreen(baseScreen);
_popRunnable = new Runnable() {
public void run() {
popScreen(_secondaryScreen);
}
};
}

public void fieldChanged(Field field, int context) {
pushScreen(_secondaryScreen);
invokeLater(_popRunnable, 2000, false);
}
}

试试这个

[liusha0225]

哥们怎么不结贴啊