How to delay code execution (draw the path) for few seconds?

Question

This is the problem about loading. My application should wait for 3 seconds and then draw path. Now, the loading message box appears within 3 seconds but the application does not wait for 3 seconds and draw immediately . Is there any problem in my coding ?

Many Thanks!!

 public void drawpath(){
       // first to do some checking
    if (sourceLat.equals("22.3366467")  && destinationLat.equals("35.68449"))
        ShowMsgDialog("Please enter the starting point and destination");
    else if (sourceLat.equals("22.3366467") )
        ShowMsgDialog("Please enter the starting point by touch");
    else if (destinationLat.equals("35.68449") )
        ShowMsgDialog("Please enter the destination by touch");

    else if (pairs != null ){
        //  go to loading function
        loading();
        // Start to draw the path
        String[] lngLat = pairs[0].split(",");

        GeoPoint startGP = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double.parseDouble(lngLat[0]) * 1E6));

         mc = mapView.getController();
         geoPoint = startGP;
         mc.setCenter(geoPoint);
         mc.setZoom(15);
         mapView.getOverlays().add(new DirectionPathOverlay(startGP, startGP));

                ...... 
        }

in the loading() function:

private void loading() {
    progressDialog = ProgressDialog.show(this, "Showing Data..", "please wait", true, false);
    new Thread()
    { 
      public void run()
      { 
        try{ 
          sleep(3000);
        }
        catch (Exception e){
          e.printStackTrace();
        }
        finally{
            progressDialog.dismiss();    
        }
      }
    }.start(); 
}

Answer 1

A handler would do the job very easily.You won't need a separate thread or AsyncTask().

Use a Handler in your Activity to delay events such as calling the method drawPath() in your case:

private RefreshHandler mRedrawHandler = new RefreshHandler(); 
 private RefreshHandler mRedrawHandler = new RefreshHandler(); 

     class RefreshHandler extends Handler {  
            @Override  
            public void handleMessage(Message msg) {  
          drawPath(); 
            }  

            public void sleep(long delayMillis) {  
              this.removeMessages(0);  
              sendMessageDelayed(obtainMessage(0), delayMillis);  
            }  
          };  

In your onCreate() of Activity (or In onClick() of any button, whenever you want to start a delay), call mRedrawHandler.sleep(3000); , drawPath(); is a method where you are starting the draw.

Answer 2

You can also do it in the following way:

new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            drawPath();
        }
    }, 5000);

This won't display any lint warnings.

Answer 3

After you spawn a new thread your code regains control and continues executing. Your additional thread is waiting not the original one.

Answer 4

for delayer in android activity

      import android.os.Handler;

in code main

  new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
  
        }
    }, 5000);

But the above code is obsolete

It is better to use the following code

Use it for Java

new Handler(Looper.getMainLooper()).postDelayed(new Runnable() {
    @Override
    public void run() {
        // Your Code
    }
}, 3000);

Use it for Kotlin

Handler(Looper.getMainLooper()).postDelayed({
        {
            //Your Code
        }
    }, 3000)