BlackBerry - waiting screen [closed]

问题:

i am developing one application in blackberry java development. I am requesting to http means i am connecting to web service .response of web service taking some time .That time i want to display some waiting screen.

Could you tell me how can i do that....

Regards Pankaj Pareek

回答1:

Basically you need to start the network request in a background thread. Once the network operation is complete you should notify the main/UI thread to change the waiting screen into the results.

To notify the main thread have a look at the link below and search for invokeLater:
http://developers.sun.com/mobility/midp/articles/blackberrydev/

Word of advice: Don't spawn to many threads at once on mobile devices. Usually they have a really low maximum number of threads.

回答2:

It's already here:
Stackoverflow - Blackberry - Loading screen with animation
Stackoverflow - Blackberry - Application loading screen

回答3:

Do one thing.... At the listner event of button write this.

         UiApplication.getUiApplication().invokeLater(new Runnable(){
            public void run(){
             Status.show("Please Wait....",b,3600);
             message.setText(test(theFile));
            }
         });

回答4:

I created a custom animated bitmap field, like this:

//thread class

public class AnimatedImageField  extends BitmapField implements Runnable
{  

private Thread thread = null;
private boolean animate=true;
private int interval = 0;
private int index=0;
private Bitmap bitmap = null;
private int frameno = 0;
private int fieldHeight=0;
private int fieldWidth=0;
private Bitmap finalbitmap = null;
private int imgHeight = 0;
private int imgWidth= 0;

public AnimatedImageField(int fieldwidth, int fieldheight, Bitmap bitmap, int frameno, int interval, long style)
{
    super(bitmap, style);
    this.interval=interval;
    this.bitmap=bitmap;
    this.frameno=frameno;
    imgHeight = bitmap.getHeight();
    int imgwidth = bitmap.getWidth();
    imgWidth=imgwidth/frameno;
    this.fieldWidth = fieldwidth;
    this.fieldHeight = fieldheight;
}

public AnimatedImageField(Bitmap bitmap, int frameno, int interval, long style)
{
    super(bitmap, style);
    this.interval=interval;
    this.bitmap=bitmap;
    this.frameno=frameno;
    imgHeight = bitmap.getHeight();
    int imgwidth = bitmap.getWidth();
    imgWidth=imgwidth/frameno;
    fieldWidth = imgWidth;
    fieldHeight = imgHeight;
}

protected void paint(Graphics graphics){
    graphics.setColor(Color.WHITE);
    graphics.fillRect(0,0,this.getPreferredWidth(), this.getPreferredHeight());

    //System.out.println("animate:"+animate);
    if ( animate )
        graphics.drawBitmap((fieldWidth-imgWidth)/2, (fieldHeight-imgHeight-50)/2, 
            imgWidth, bitmap.getHeight(), bitmap , imgWidth*index, 0);     
    else
        graphics.drawBitmap((fieldWidth-finalbitmap.getWidth())/2, (fieldHeight-finalbitmap.getHeight()-50)/2, 
            finalbitmap.getWidth(), finalbitmap.getHeight(), finalbitmap , 0, 0);     
}

public int getPreferredWidth()
{
        return fieldWidth;
}

public int getPreferredHeight()
{
        return fieldHeight;
}

protected void layout(int arg0, int arg1)
{
        setExtent(getPreferredWidth(), getPreferredHeight());
}

public void startAnimation(){
     //System.out.println("startAnimation");
    animate=true;
    thread = new Thread(this);
    thread.start();
}

public void updateLayout(int height, int width){
    //System.out.println("updateLayout:height:"+height);
    this.fieldHeight=height;
    this.fieldWidth=width;
    super.updateLayout();
}

public void stopAnimation(Bitmap bitmap){
    //System.out.println("stopAnimation");        
    this.finalbitmap=bitmap;
    animate=false;
}    

public void stopAnimation(){
    //System.out.println("stopAnimation");
    animate=false;
}    

public void run(){
        while(animate){ 
            //System.out.println("run:animate:"+animate);
            try{ Thread.sleep(interval);}catch(Exception e){}
            if ( index+1>=frameno )
                index=0;
            else
                index++;
            invalidate();
        }
}

}

call from : //loading

    Bitmap load_icon = Bitmap.getBitmapResource("loading.png");
    AnimatedImageField spinner = new AnimatedImageField(Display.getWidth(), Display.getHeight(), load_icon,
            12, 100, Field.FIELD_HCENTER | Field.FOCUSABLE
            | Field.FIELD_VCENTER);
    spinner.startAnimation();
    add(spinner);