Develop an extension

So, supp guys! Lets develop some extension today !

We will use android.widget.NumberPicker

Lets Start ! :wink:

Step 1

Write Package Name for Extension

package com.yourname.Aixname;

Step 2

Write imports

import android.content.Context; // for context variable

import com.google.appinventor.components.annotations.*; // Annotations Used In Aix

import com.google.appinventor.components.common.*; // For component Category

import com.google.appinventor.components.runtime.*; // We need for AndroidViewComponent .... etc

import android.widget.NumberPicker; // obviously, for our NumberPicker

import android.widget.FrameLayout; // We will add our Number Picker inside FrameLayout 

FrameLayout : Allows you to Add Views inside it

Step3
Info about your extension

@DesignerComponent(

        version = 1, // version of your aix

        description = "", // write description about aix

        category = ComponentCategory.EXTENSION, // we assign a category to extension

        nonVisible = true, // yes, its nonvisible because aixs cant be visible components directly

        iconName = "") // icon for your extension

@SimpleObject(external = true) // If u remove it, extension will compile successfully but no aix will be present so, dont miss it :)

Step4
Its constructor part of extension, you can execute functions once the app starts/inits

public class Numby extends AndroidNonvisibleComponent {
// Numby is class name, moreover aix name
// We extend our class to be AndroidNonvisibleComponent (as aixs need to be one :)
    private Context context; // context for our extension (context is kinda like environment in which our app runs)

    private NumberPicker numby; // our number picker obviously :)

    public Numby(ComponentContainer container){ // component container part !

        super(container.$form());

        this.context = container.$context(); // context/ environment of our app

        numby = new NumberPicker(context); // we create a new number picker object

        numby.setOnScrollListener(new NumberPicker.OnScrollListener(){ // we set a on scroll listener to fire events !

            @Override

            public void onScrollStateChange (NumberPicker view, 

                int scrollState){ // ScrollStateChanged, now we will call functions to dispatch events

               ScrollStateChange(scrollState); // event will be fired !

                }

        });

        numby.setOnValueChangedListener(new NumberPicker.OnValueChangeListener(){ // ValueChangedListener, kinda same work as we saw in previous listener did, it will fire events !

            @Override

            public void onValueChange (NumberPicker picker, 

                int oldVal, 

                int newVal){ //ValueChanged, now we will call function to dispatch our event !

                    ValueChanged(oldVal, newVal); // event will be fired ! :)

                }

        });

    }

SO now we completed constructor part !

Step5
now Code Part ! Now lets write code for functions :slight_smile:

@SimpleFunction

    public void AddToView(AndroidViewComponent view){ // Adds our numberPicker created in constructor to a view(framelayout)
// AndroidViewComponent accepts an arrangement

    FrameLayout fm = (FrameLayout) view.getView(); // gets framelayout view from androidviewcomponent

    fm.addView(numby); // now finally adds our previously created numberpicker !

    }

Now we need to do events ryt? lets do :slight_smile:


@SimpleEvent

    public void ScrollStateChange(int scrollState){ // int scrollState passes state of scroll provided to us by onScrollStateChange

        EventDispatcher.dispatchEvent(this, "ScrollStateChange", scrollState); // event dispatcher dispatches event

    }

    @SimpleEvent

    public void ValueChanged(int oldVal, int newVal){ // int oldVal and newVal pass values passed to ur by onValueChange 

        EventDispatcher.dispatchEvent(this, "ValueChanged", oldVal, newVal);  // event dispatcher dispatches event

    }

Now some last property stuff will complete aix :wink:

@SimpleProperty

    public void SelectionDividerHeight (int height){ // property for SelectionDividerHeight, input provided here is int

        numby.setSelectionDividerHeight(height); // sets SelectionDividerHeight via provided input(int)

    }

    @SimpleProperty

    public void TextColor(int color){ // Property of TextColor

        numby.setTextColor(color); // sets text color of number picker

    }

    @SimpleProperty

    public void TextSize(float size){ //property for text size

        numby.setTextSize(size); // sets text size

    }

    @SimpleProperty

    public void Value(int v){ // Property to set current value of picker

        numby.setValue(v); // sets value of number picker via provided value(int)

    }

    @SimpleProperty

    public void WrapSelectorWheel(boolean b){ // Property of WrapSelectorWheel

        numby.setWrapSelectorWheel(b); // sets if SelectorWheel must be wrapped via provided boolean

    }
@SimpleProperty

    public void MaxValue(int kid){ // Property for MaxValue of Number

        numby.setMaxValue(kid); // sets MaxValue of Number Picker via provided input

    }

    @SimpleProperty

    public void MinValue(int kid){ // Property for MinValue of number picker

        numby.setMinValue(kid); // sets minvalue of number picker via provided value

    }

mmm, last but not least, lets pass values

@SimpleProperty

    public int GetMaxValue(){ // Property that passes max value we setted for number pickers

        return numby.getMaxValue(); // return max value

    }

    @SimpleProperty

    public int GetMinValue(){ // Property that passes min value we setted for number pickers

        return numby.getMinValue(); // return min value

    }
@SimpleProperty

    public int GetSelectionDividerHeight(){ // Property that passes SelectionDividerHeight setted for numberPicker

        return numby.getSelectionDividerHeight(); // return SelectionDividerHeight

    }
@SimpleProperty

    public int GetTextColor(){ // Property that passes text color of Number Picker

        return numby.getTextColor(); // return TextColor

    }

    @SimpleProperty

    public float GetTextSize(){ // Property that passes text size of Number Picker

        return numby.getTextSize(); // return textSize

    }

    @SimpleProperty

    public int GetValue(){ // Property that passes value of NumberPicker

        return numby.getValue(); // returns Value

    }

So we are done ! :cake:

So, source will look like :arrow_down: :

package com.kabby.Numby;

import android.content.Context; // for context variable

import com.google.appinventor.components.annotations.*; // Annotations Used In Aix

import com.google.appinventor.components.common.*; // For component Category

import com.google.appinventor.components.runtime.*; // We need for AndroidViewComponent .... etc

import android.widget.NumberPicker; // obviously, for our NumberPicker

import android.widget.FrameLayout; // We will add our Number Picker inside FrameLayout

@DesignerComponent(

        version = 1,

        description = "",

        category = ComponentCategory.EXTENSION,

        nonVisible = true,

        iconName = "")

@SimpleObject(external = true)

public class Numby extends AndroidNonvisibleComponent {

    private NumberPicker numby;

    public Numby(ComponentContainer container){

        super(container.$form());

        this.context = container.$context();

        numby = new NumberPicker(context);

        numby.setOnScrollListener(new NumberPicker.OnScrollListener(){

            @Override

            public void onScrollStateChange (NumberPicker view, 

                int scrollState){

               ScrollStateChange(scrollState);

                }

        });

        numby.setOnValueChangedListener(new NumberPicker.OnValueChangeListener(){

            @Override

            public void onValueChange (NumberPicker picker, 

                int oldVal, 

                int newVal){

                    ValueChanged(oldVal, newVal);

                }

        });

    }

    @SimpleFunction

    public void AddToView(AndroidViewComponent view){

    FrameLayout fm = (FrameLayout) view.getView();

    fm.addView(numby);

    }

    @SimpleProperty

    public int GetMaxValue(){

        return numby.getMaxValue();

    }

    @SimpleProperty

    public int GetMinValue(){

        return numby.getMinValue();

    }

    @SimpleProperty

    public int GetSelectionDividerHeight(){

        return numby.getSelectionDividerHeight();

    }

    @SimpleProperty

    public int GetSolidColor(){

       return numby.getSolidColor();

    }

    @SimpleProperty

    public int GetTextColor(){

        return numby.getTextColor();

    }

    @SimpleProperty

    public float GetTextSize(){

        return numby.getTextSize();

    }

    @SimpleProperty

    public int GetValue(){

        return numby.getValue();

    }

    @SimpleFunction

    public void ScrollBy(int x, int y){

        numby.scrollBy(x, y);

    }

    @SimpleProperty

    public void Enabled(boolean bb){

        numby.setEnabled(bb);

    }

    @SimpleProperty

    public void MaxValue(int kid){

        numby.setMaxValue(kid);

    }

    @SimpleProperty

    public void MinValue(int kid){

        numby.setMinValue(kid);

    }

    @SimpleProperty

    public void OnLongPressUpdateInterval(long mm){

    numby.setOnLongPressUpdateInterval(mm);

        }

    @SimpleEvent

    public void ScrollStateChange(int scrollState){

        EventDispatcher.dispatchEvent(this, "ScrollStateChange", scrollState);

    }

    @SimpleEvent

    public void ValueChanged(int oldVal, int newVal){

        EventDispatcher.dispatchEvent(this, "ValueChanged", oldVal, newVal);

    }

    @SimpleProperty

    public void SelectionDividerHeight (int height){

        numby.setSelectionDividerHeight(height);

    }

    @SimpleProperty

    public void TextColor(int color){

        numby.setTextColor(color);

    }

    @SimpleProperty

    public void TextSize(float size){

        numby.setTextSize(size);

    }

    @SimpleProperty

    public void Value(int v){

        numby.setValue(v);

    }

    @SimpleProperty

    public void WrapSelectorWheel(boolean b){

        numby.setWrapSelectorWheel(b);

    }

}

If you find any mistake, kindly do report it

Description for every line of code is written in form of comments ()

Thanks for paying a visit !
yours

Kiddo :stuck_out_tongue_winking_eye:

22 Likes

Amazing Tutorial @UnknownBeast :partying_face: :partying_face: :partying_face:

Will try this today :grin:

3 Likes

nice tutorial it will help many people

3 Likes

Awesome tutorial :+1:and very good explanation

:innocent:

3 Likes

Congratulations ! Great guide. Very good explained.
Great way to teach.
:clap:

5 Likes

Loved it :heart:, thanks for the super cool guide :sunglasses:

3 Likes

Amazing Tutorial @UnknownBeast :partying_face: :partying_face: :partying_face:

1 Like

What an Explanation.

2 Likes

Amazing Precious Guide :love_you_gesture: :heart:

1 Like

Such a nice guide. Iā€™m trying to learn
but found minor statement missing :point_down:

private Context context; (Missing this line in full source code section)

Or maybe

private final Context context;
//context is not changed after declaring value so

:yum:

2 Likes