The goal of this article is to control the small aircraft to move left and right, avoid bullets, and hit bosses.

This section implementsStart menu interface

1. First, copy the resource files

2. Divide the game state

public static final int game_menu=0;//game menu
 public static final int gameing=1;//in game
 public static final int game_win=2;//game victory
 public static final int game_lost=3;//game failed
 public static final int game_pause=-1;//game menu
 //Current game state (default is initially in the game menu interface)
 public static int gamestate=game_menu;

Define five states

After defining the method, in the drawing method, press the entity key, lift the method,Touch screen monitoring,Logical method,switch

//Add this in those methods
  switch (gamestate) {
  case game_menu:
   break;
  case gameing:
   break;
  case game_win:
   break;
  case game_lost:
   break;
  case game_pause:
   break;
  default:
   break;
  }

Let's declare some more

//Declare a resources instance to load images
 private resources res=this.getresources ();
 //Declare the image resources used by the game (picture declaration)
 private bitmap bmpbackground;//game background
 private bitmap bmpboom;//explosion effect
 private bitmap bmpboosboom;//boos explosion effect
 private bitmap bmpbutton;//Game start button
 private bitmap bmpbuttonpress;//The game start button is clicked
 private bitmap bmpenemyduck;//Monster duck
 private bitmap bmpenemyfly;//Monster Fly
 private bitmap bmpenemyboos;//monster pig head boos
 private bitmap bmpgamewin;//Game victory background
 private bitmap bmpgamelost;//Game failure background
 private bitmap bmpplayer;//Game lead plane
 private bitmap bmpplayerhp;//Protect plane health
 private bitmap bmpmenu;//Menu background
 public static bitmap bmpbullet;//bullet
 public static bitmap bmpenemybullet;//enemy bullets
 public static bitmap bmpbossbullet;//boss bullet

Initialization game

/**
 * surfaceview view creation,Respond to this function
 * /
 @override
 public void surfacecreated (surfaceholder holder) {
 screenw=this.getwidth ();
 screenh=this.getheight ();
 initgame ();
 flag=true;
 //instance thread
 th=new thread (this);
 //start the thread
 th.start ();
 }

/**
 * Load game resources
 * /
 private void initgame () {
 //Load game resources
 bmpbackground=bitmapfactory.decoderesource (res, r.drawable.background);
 bmpboom=bitmapfactory.decoderesource (res, r.drawable.boom);
 bmpboosboom=bitmapfactory.decoderesource (res, r.drawable.boos_boom);
 bmpbutton=bitmapfactory.decoderesource (res, r.drawable.button);
 bmpbuttonpress=bitmapfactory.decoderesource (res, r.drawable.button_press);
 bmpenemyduck=bitmapfactory.decoderesource (res, r.drawable.enemy_duck);
 bmpenemyfly=bitmapfactory.decoderesource (res, r.drawable.enemy_fly);
 bmpenemyboos=bitmapfactory.decoderesource (res, r.drawable.enemy_pig);
 bmpgamewin=bitmapfactory.decoderesource (res, r.drawable.gamewin);
 bmpgamelost=bitmapfactory.decoderesource (res, r.drawable.gamelost);
 bmpplayer=bitmapfactory.decoderesource (res, r.drawable.player);
 bmpplayerhp=bitmapfactory.decoderesource (res, r.drawable.hp);
 bmpmenu=bitmapfactory.decoderesource (res, r.drawable.menu);
 bmpbullet=bitmapfactory.decoderesource (res, r.drawable.bullet);
 bmpenemybullet=bitmapfactory.decoderesource (res, r.drawable.bullet_enemy);
 bmpbossbullet=bitmapfactory.decoderesource (res, r.drawable.boosbullet);
 }

Menu gamemenu

Menu

Includes initial draw button and background image

package com.gsf;
import android.graphics.bitmap;
import android.graphics.canvas;
import android.graphics.paint;
import android.view.motionevent;
/**
 *
 * @author liuml
 * @time May 27, 2016 5:43:34 PM
 * /
public class gamemenu {
 //menu background image
 private bitmap bmpmenu;
 //button image resource (pressed and not clicked)
 private bitmap bmpbutton, bmpbuttonpress;
 //button coordinates
 private int btnx, btny;
 //Whether the button is pressed
 private boolean ispress;
 //menu initialization
 public gamemenu (bitmap bmpmenu, bitmap bmpbutton, bitmap bmpbuttonpress) {
 this.bmpmenu=bmpmenu;
 this.bmpbutton=bmpbutton;
 this.bmpbuttonpress=bmpbuttonpress;
 //center x, y immediately at the bottom of the screen
 btnx=mysurfaceview.screenw/2-bmpbutton.getwidth ()/2;
 btny=mysurfaceview.screenh-bmpbutton.getheight ();
 ispress=false;
 }
 public void draw (canvas canvas, paint paint) {
 //draw the menu background
 canvas.drawbitmap (bmpmenu, 0, 0, paint);
 if (ispress) {
  canvas.drawbitmap (bmpbuttonpress, btnx, btny, paint);
 } else {
  canvas.drawbitmap (bmpbutton, btnx, btny, paint);
 }
 }
 public void ontouchevent (motionevent event) {
 //Get the current touch position
 int pointx=(int) event.getx ();
 int pointyy=(int) event.gety ();
 //when the user is pressing and moving
 if (event.getaction () == motionevent.action_down
  || event.getaction () == motionevent.action_move) {
  //determine whether the user clicked the button
  if (pointx>btnx&&pointx<btnx + bmpbutton.getwidth ()) {
  if (pointyy>btny&&pointyy<btny + bmpbutton.getheight ()) {
   ispress=true;
  } else {
   ispress=false;
  }
  } else {
  ispress=false;
  }
  //when used for lifting action
 } else if (event.getaction () == motionevent.action_up) {
  //determine whether to click the button when lifting,Prevent users from moving elsewhere
  if (pointx>btnx&&pointx<btnx + bmpbutton.getwidth ()) {
  if (pointyy>btny&&pointyy<btny + bmpbutton.getheight ()) {
   ispress=false;//Reset after lifting Restore the button state to not pressed
   //Change the current game state to start the game
   mysurfaceview.gamestate=mysurfaceview.gameing;
  }
  }
 }
 }
}
</p>
<p>

Then use gamemenu in mysurfaceview using the menu class

public class mysurfaceview extends surfaceview implements callback, runnable {
 private surfaceholder sfh;
 private paint paint;
 private thread th;
 private boolean flag;
 private canvas canvas;
 //1 define the game state constant
 public static final int game_menu=0;//game menu
 public static final int gameing=1;//in game
 public static final int game_win=2;//game victory
 public static final int game_lost=3;//game failed
 public static final int game_pause=-1;//game menu
 //Current game state (default is initially in the game menu interface)
 public static int gamestate=game_menu;
 //Declare a resources instance to load images
 private resources res=this.getresources ();
 //Declare the image resources used by the game (picture declaration)
 private bitmap bmpbackground;//game background
 private bitmap bmpboom;//explosion effect
 private bitmap bmpboosboom;//boos explosion effect
 private bitmap bmpbutton;//game start button
 private bitmap bmpbuttonpress;//the game start button is clicked
 private bitmap bmpenemyduck;//Monster Duck
 private bitmap bmpenemyfly;//monster fly
 private bitmap bmpenemyboos;//monster pig head boos
 private bitmap bmpgamewin;//game victory background
 private bitmap bmpgamelost;//Game failure background
 private bitmap bmpplayer;//Game lead plane
 private bitmap bmpplayerhp;//Leader plane health
 private bitmap bmpmenu;//menu background
 public static bitmap bmpbullet;//bullet
 public static bitmap bmpenemybullet;//enemy bullets
 public static bitmap bmpbossbullet;//boss bullet
 public static int screenw;
 public static int screenh;
 //
 private gamemenu gamemenu;
 /**
 * surfaceview initialization function
 * /
 public mysurfaceview (context context) {
 super (context);
 sfh=this.getholder ();
 sfh.addcallback (this);
 paint=new paint ();
 paint.setcolor (color.white);
 paint.setantialias (true);
 setfocusable (true);
 }
 /**
 * surfaceview view creation,Respond to this function
 * /
 @override
 public void surfacecreated (surfaceholder holder) {
 screenw=this.getwidth ();
 screenh=this.getheight ();
 initgame ();
 flag=true;
 //instance thread
 th=new thread (this);
 //start the thread
 th.start ();
 }
 /**
 * Load game resources
 * /
 private void initgame () {
 //Load game resources
 bmpbackground=bitmapfactory
  .decoderesource (res, r.drawable.background);
 bmpboom=bitmapfactory.decoderesource (res, r.drawable.boom);
 bmpboosboom=bitmapfactory.decoderesource (res, r.drawable.boos_boom);
 bmpbutton=bitmapfactory.decoderesource (res, r.drawable.button);
 bmpbuttonpress=bitmapfactory.decoderesource (res,  r.drawable.button_press);
 bmpenemyduck=bitmapfactory.decoderesource (res, r.drawable.enemy_duck);
 bmpenemyfly=bitmapfactory.decoderesource (res, r.drawable.enemy_fly);
 bmpenemyboos=bitmapfactory.decoderesource (res, r.drawable.enemy_pig);
 bmpgamewin=bitmapfactory.decoderesource (res, r.drawable.gamewin);
 bmpgamelost=bitmapfactory.decoderesource (res, r.drawable.gamelost);
 bmpplayer=bitmapfactory.decoderesource (res, r.drawable.player);
 bmpplayerhp=bitmapfactory.decoderesource (res, r.drawable.hp);
 bmpmenu=bitmapfactory.decoderesource (res, r.drawable.menu);
 bmpbullet=bitmapfactory.decoderesource (res, r.drawable.bullet);
 bmpenemybullet=bitmapfactory.decoderesource (res,  r.drawable.bullet_enemy);
 bmpbossbullet=bitmapfactory
  .decoderesource (res, r.drawable.boosbullet);
 //Menu class instantiation
 gamemenu=new gamemenu (bmpmenu, bmpbutton, bmpbuttonpress);
 }
 /**
 * Game drawing
 * /
 public void mydraw () {
 try {
  canvas=sfh.lockcanvas ();
  if (canvas!=null) {
  canvas.drawcolor (color.white);
  //The drawing function draws differently depending on the state of the game
  switch (gamestate) {
  case game_menu:
   gamemenu.draw (canvas, paint);
   break;
  case gameing:
   break;
  case game_win:
   break;
  case game_lost:
   break;
  case game_pause:
   break;
  default:
   break;
  }
  }
 } catch (exception e) {
  //todo:handle exception
 } finally {
  if (canvas!=null)
  sfh.unlockcanvasandpost (canvas);
 }
 }
 /**
 * Touch screen event monitoring
 * /
 @override
 public boolean ontouchevent (motionevent event) {
 switch (gamestate) {
 case game_menu:
  gamemenu.ontouchevent (event);
  break;
 case gameing:
  break;
 case game_win:
  break;
 case game_lost:
  break;
 case game_pause:
  break;
 }
 return true;
 }
 /**
 * Key event monitoring
 * /
 @override
 public boolean onkeydown (int keycode, keyevent event) {
 switch (gamestate) {
 case game_menu:
  break;
 case gameing:
  break;
 case game_win:
  break;
 case game_lost:
  break;
 case game_pause:
  break;
 }
 return super.onkeydown (keycode, event);
 }
 @override
 public boolean onkeyup (int keycode, keyevent event) {
 switch (gamestate) {
 case game_menu:
  break;
 case gameing:
  break;
 case game_win:
  break;
 case game_lost:
  break;
 case game_pause:
  break;
 }
 return super.onkeyup (keycode, event);
 }
 /**
 * Game logic
 * /
 private void logic () {
 switch (gamestate) {
 case game_menu:
  break;
 case gameing:
  break;
 case game_win:
  break;
 case game_lost:
  break;
 case game_pause:
  break;
 }
 }
 @override
 public void run () {
 while (flag) {
  long start=system.currenttimemillis ();
  mydraw ();
  logic ();
  long end=system.currenttimemillis ();
  try {
  if (end-start<50) {
   thread.sleep (50-(end-start));
  }
  } catch (interruptedexception e) {
  e.printstacktrace ();
  }
 }
 }
 /**
 * surfaceview view state changes,Respond to this function
 * /
 @override
 public void surfacechanged (surfaceholder holder, int format, int width,  int height) {
 }
 /**
 * When the surfaceview view dies,Respond to this function
 * /
 @override
 public void surfacedestroyed (surfaceholder holder) {
 flag=false;
 }
}

Effect picture: