Animierte Zeichenflächen mit "invalidate"

Main.java

package com.example;

/** Verschiedene statische Hilfsmethoden für Android-Programmierung. */
final class Android
{
  /** Laufender Zähler für Ausgaben einer Aufzeichnung. */
  static long logcount = 0;
  /** Ausgabe einer Information in das Logbuch.
  @param object eine java.lang.Object-Referenz, die wie durch einen Aufruf
  der Methode {@link java.lang.String#valueOf(java.lang.Object)} ein
  {@link java.lang.String}-Objekt erzeugt, welches dann mit dem Etikett
  "com.example" und der Einstufung als Information in das Logbuch
  geschrieben wird. */
  final static void println( final java.lang.Object object )
  { try{ java.lang.Thread.sleep( 50 ); } /* otherwise slow logcat might miss some logs */
    catch( final java.lang.InterruptedException exception ){ } /* modified */
    android.util.Log.i
    ( "com.example", "[" + logcount++ + "] " + java.lang.String.valueOf( object )); }}


public class Main extends android.app.Activity
{

  public class Canvas extends android.view.View
  { private final java.util.Random generator = new java.util.Random();
    public Canvas( final android.content.Context context ){ super( context ); }
    boolean first = true;
    boolean veryFirst = true;
    int oldX = -1;
    int oldY = -1;
    double xc = 0;
    double yc = 0;
    int x = -1;
    int y = -1;
    double vx = 0;
    double vy = 0;
    double j = 1;

    android.graphics.Canvas screen = new android.graphics.Canvas();
    android.graphics.Bitmap bitmap;
    android.graphics.Paint paint;
    android.graphics.Paint bgPaint;


    protected void onDraw( final android.graphics.Canvas canvas )
    { boolean border = false;
      boolean sticked = false;

      for( int i = 0; i < j; ++i )
      { //Android.println( "i = " + i + ", j = " + j );
        if( first )
        { // canvas.drawRGB( 0, 0, 0 );
          switch( 1 )
          { case 0:
            xc = canvas.getWidth() / 2;
            yc = canvas.getHeight() / 2;
            break;
            case 1:
            xc = generator.nextInt( canvas.getWidth() );
            yc = generator.nextInt( canvas.getHeight() );
            break; }
          vx = 0;
          vy = 0;
          oldX = -1;
          oldY = -1;
          border = false;
          sticked = false;
          if( veryFirst )
          { paint = new android.graphics.Paint();
            paint.setStyle( android.graphics.Paint.Style.FILL );
            paint.setColor( android.graphics.Color.WHITE );
            bgPaint = new android.graphics.Paint();
            bgPaint.setStyle( android.graphics.Paint.Style.FILL );
            bgPaint.setColor( android.graphics.Color.BLACK );
            bitmap = android.graphics.Bitmap.createBitmap( canvas.getWidth(), canvas.getHeight(), android.graphics.Bitmap.Config.ARGB_8888 );
            screen.setBitmap( bitmap );
            screen.drawRGB( 0, 0, 0 );
            veryFirst = false; }
          first = false; }
        else
        { vx = vx +( 1 - generator.nextInt( 3 ))/10.0; if( vx > 0.8 )vx = 0.8; if( vx < -0.8 )vx = -0.8;
          vy = vy +( 1 - generator.nextInt( 3 ))/10.0; if( vy > 0.8 )vy = 0.8; if( vy < -0.8 )vy = -0.8;
          xc = xc + vx;
          yc = yc + vy;
          x =( int )xc;
          y =( int )yc;
          border = false; if( false
            || x >= canvas.getWidth()
            || y >= canvas.getHeight()
            || x < 0
            || y < 0 )border = true;
          sticked = false;
          if( oldX >= 0 && oldY >= 0 )
          { if( !border )screen.drawPoint( oldX, oldY, bgPaint ); }
          if( !border &&( x != oldX || y != oldY )&&
            ( y > 0 &&
              ( false
                ||( x > 0                 && bitmap.getPixel( x - 1, y - 1 )== android.graphics.Color.WHITE )
                ||(                          bitmap.getPixel( x,     y - 1 )== android.graphics.Color.WHITE )
                ||( x < canvas.getWidth() - 1 && bitmap.getPixel( x + 1, y - 1 )== android.graphics.Color.WHITE ))

              ||( x > 0                 && bitmap.getPixel( x - 1, y )== android.graphics.Color.WHITE )
              ||( x < canvas.getWidth() - 1 && bitmap.getPixel( x + 1, y )== android.graphics.Color.WHITE )

              || y < canvas.getHeight() - 1 &&
              ( false
                ||( x > 0                 && bitmap.getPixel( x - 1, y + 1 )== android.graphics.Color.WHITE )
                ||(                          bitmap.getPixel( x,     y + 1 )== android.graphics.Color.WHITE )
                ||( x < canvas.getWidth() - 1 && bitmap.getPixel( x + 1, y + 1 )== android.graphics.Color.WHITE ))

              || false ))sticked = true;
          if( !border )if( x != oldX || y != oldY )
          { // myBitmap.setPixel(x, y, Color.rgb(45, 127, 0));
            screen.drawPoint( x, y, paint ); oldX = x; oldY = y; }}
          if( border || sticked )first = true; }
      j = j < 100000 ? j * 1.001 : j;
      canvas.drawBitmap( bitmap, 0, 0, bgPaint );
      if( j < 1000 )canvas.drawCircle( x, y,( float )( 1000 / j > 10 ? 10 : 1000 / j ), paint );
      super.invalidate(); }}

    /*canvas.drawPoint(X, Y, paint);
    Here is how you initalize Object of class android.graphics.Paint i.e paint
    Paint paint = new Paint();
    paint.setStyle(Paint.Style.FILL);
    paint.setColor(Color.WHITE);*/

  @java.lang.Override public void onCreate( final android.os.Bundle bundle )
  { super.onCreate( bundle );
    Main.this.requestWindowFeature( android.view.Window.FEATURE_NO_TITLE );
    Main.this.getWindow().getDecorView().setSystemUiVisibility
    ( 0
      | android.view.View.SYSTEM_UI_FLAG_LAYOUT_STABLE
      | android.view.View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
      | android.view.View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
      | android.view.View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
      | android.view.View.SYSTEM_UI_FLAG_FULLSCREEN /* hides status bar */
      | android.view.View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY );
    setContentView( new Canvas( this ) ); }}