Use runtime component's event

Soham_Shah · December 8, 2020, 8:56am

Hi,
I want to use Clock component's event when Clock.Timer in my extension but i don't want to show it as a event handler block in my extension, i just want to use it to trigger other event so can anybody tell me how can i do it?

MohamedTamer · December 8, 2020, 9:05am

You can use the TimerInternal class, which allows you to add timers to your component / extension:

github.com

mit-cml/appinventor-sources/blob/master/appinventor/components/src/com/google/appinventor/components/runtime/util/TimerInternal.java

// -*- mode: java; c-basic-offset: 2; -*-
// Copyright 2009-2011 Google, All Rights reserved
// Copyright 2011-2012 MIT, All rights reserved
// Released under the Apache License, Version 2.0
// http://www.apache.org/licenses/LICENSE-2.0

package com.google.appinventor.components.runtime.util;

import com.google.appinventor.components.runtime.AlarmHandler;

import android.os.Handler;

/**
 * Helper class for components containing timers, such as Timer and Sprite.
 *
 */
public final class TimerInternal implements Runnable {

  // Android message handler used as a timer
  private Handler handler;

This file has been truncated. show original

See here an example with the Sprite class:

github.com

mit-cml/appinventor-sources/blob/399dc0cf43c89be85d0dbc2f6f9e76eaadabf2b7/appinventor/components/src/com/google/appinventor/components/runtime/Sprite.java#L118


if (!(container instanceof Canvas)) {
  throw new IllegalArgumentError("Sprite constructor called with container " + container);
}
this.canvas = (Canvas) container;
this.canvas.addSprite(this);


// Maintain a list of collisions.
registeredCollisions = new HashSet<Sprite>();


// Set in motion.
timerInternal = new TimerInternal(this, DEFAULT_ENABLED, DEFAULT_INTERVAL, handler);


this.form = container.$form();


// Set default property values.
OriginAtCenter(DEFAULT_ORIGIN_AT_CENTER);
Heading(0);  // Default initial heading
Enabled(DEFAULT_ENABLED);
Interval(DEFAULT_INTERVAL);
Speed(DEFAULT_SPEED);
Visible(DEFAULT_VISIBLE);

github.com

mit-cml/appinventor-sources/blob/399dc0cf43c89be85d0dbc2f6f9e76eaadabf2b7/appinventor/components/src/com/google/appinventor/components/runtime/Sprite.java#L990


      qy >= yTop && qy < yTop + Height();
}


// Convenience methods for dealing with hitting the screen edge and collisions


// AlarmHandler implementation


/**
 * Moves and redraws sprite, registering changes.
 */
public void alarm() {
  // This check on initialized is currently redundant, since registerChange()
  // checks it too.
  if (initialized && speed != 0) {
    updateCoordinates();
    registerChange();
  }
}


// Component implementation

Note, you will need to implement the AlarmHandler interface in your class.

Alaqmar_Bohori · December 8, 2020, 9:11am

Havent you already opened a thread here?