$ define（）在java android studio源代码中做了什么以及如何查看和更改它

Question

我正在看Android Studio中的一些java代码，它编译为Android的apk。在这段代码中，$ define（）{....}中有初始化代码。这是做什么的，我怎么看到并修改它。代码注释表明它与Java中的main类似。

以下是代码：

package com.example.bparent.redbutton3;

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

//package com.example.paintpot;

import com.google.appinventor.components.runtime.HandlesEventDispatching;
import com.google.appinventor.components.runtime.Form;
import com.google.appinventor.components.runtime.EventDispatcher;
import com.google.appinventor.components.runtime.Component;

import com.google.appinventor.components.runtime.HorizontalArrangement;
import com.google.appinventor.components.runtime.Button;
import com.google.appinventor.components.runtime.Camera;
import com.google.appinventor.components.runtime.Canvas;

public class Screen1 extends Form implements HandlesEventDispatching
{

    private float dotSize;

    private Canvas canvas1;
    private HorizontalArrangement horizontalArrangement1;
    private Button redButton;
    private Button blueButton;
    private Button greenButton;
    private Button bigButton;
    private Button smallButton;
    private Button takePictureButton;
    private Camera camera1;

    protected void $define()
    {
        this.Title("Paint Pot");
        this.Icon("kitty.png");
        dotSize = 2;
        canvas1 = new Canvas( this );
        canvas1.Height( 300 );
        canvas1.Width(LENGTH_FILL_PARENT);
        canvas1.BackgroundImage( "kitty.png" );

        canvas1.PaintColor(COLOR_RED);

        horizontalArrangement1 = new HorizontalArrangement( this );
        horizontalArrangement1.Width(LENGTH_FILL_PARENT);

Answer 1

$define是Java中的有效标识符，没有什么特别之处。因此代码定义了一个名为$define的受保护方法。