Why does not my Alert pop up? My intention is that the user needs to confirm the information before he/she can continue
Alert a =new Alert(null,"Your changes has been saved", null, AlertType.CONFIRMATION);
a.setTimeout(Alert.FOREVER);
midlet.getDisplay().setCurrent(a);
> Alert a = new Alert(null, "Your changes has
> been saved", null, AlertType.CONFIRMATION);
> a.setTimeout(Alert.FOREVER);
> midlet.getDisplay().setCurrent(a);
What is "midlet" refers to? Is it a reference to an object of your midlet class? In that case what is getDisplay()? Is it a method in your midlet? It should not be.. as it is a static method of Display class.
The actual code will be like this:
import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
public class myAlert extends MIDlet {
protected void startApp() {
Display display=Display.getDisplay(this);
Alert a = new Alert(null, "Your changes has been saved", null, AlertType.CONFIRMATION);
a.setTimeout(Alert.FOREVER);
display.setCurrent(a);
}
protected void destroyApp(boolean unconditional) {
}
protected void pauseApp() {
}
}
I think I do like you guys show.
midlet refers to my midlet class, and in it a method like this exists. Thats why I think this would work but it does not
public Display getDisplay()
{
return Display.getDisplay(this);
}
Ok, here comes a bigger piece of code!
My start class, the MIDLet has a reference that is passed around in the application when you switch different things on the screen.
In this MIDLet class there are a bunch of alert-methods that work like wrappers for launching an Alert.
For example we have a private method (it is called from a public one that pretty much just call this one)
private void alert(String text, AlertType type, boolean blocking) {
Alert alert = new Alert(null,text,null,type);
alert.setTimeout(Alert.FOREVER);
Displayable current;
if(blocking) {
final Object alertLock = new Object();
alert.setCommandListener(new CommandListener() {
public void commandAction(Command cmd, Displayable disp) {
synchronized (alertLock) {
alertLock.notify();
}
}
});
//Store current and show alert
current = waitUntilDisplayIsNotAlert();
setDisplay(alert);
//Wait for user to select
synchronized (alertLock) {
try {
alertLock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
//Return to previous display
setDisplay(current);
} else {
current = waitUntilDisplayIsNotAlert();
getDisplay().setCurrent(alert, current);
}
current = null;
}
If blocking = true it hangs, and if blocking = false it is never shown.
private synchronized Displayable waitUntilDisplayIsNotAlert() {
while(getDisplay().getCurrent() instanceof Alert) {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return getDisplay().getCurrent();
}
Message was edited by:
sandsater
