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我遵循gamecodeschool.com的一个教程来制作'Android 2D Scrolling Shooter'游戏。currentViewportWorldCentre未解决
我对着错误：
"Cannot resolve symbol 'currentViewportWorldCentre'"
请帮助。以下我的文件GameView.java。您可以从gamecodeschool.com获取其余文件。
package com.wtech.shooterboy;
import android.content.Context;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PointF;
import android.graphics.Rect;
import android.graphics.RectF;
import android.media.AudioManager;
import android.media.SoundPool;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Random;
public class GameView extends SurfaceView implements Runnable {
// A handy Random instance
Random random = new Random();
// For sound FX
private SoundPool soundPool;
private int shootID = -1;
private int damageBuildingID = -1;
// This is an instance of an inner class
// See end of this class for code
HUD hud;
// How big is the world?
// Change these for lots of fun...
// And a slow game
int worldWidth = 0;
int targetWorldWidth = 500;
int targetWorldHeight = 150;
int groundLevel = 145;
// For the returned rectangle from the viewport
// These we will use in the main game loop, multiple times
// Saves creating new instances each frame
RectF convertedRect = new RectF();
PointF convertedPointA = new PointF();
PointF convertedPointB = new PointF();
PointF convertedPointC = new PointF();
PointF tempPointF = new PointF();
// This is our thread
private Thread gameThread = null;
// Our SurfaceHolder to lock the surface before we draw our graphics
private SurfaceHolder ourHolder;
// A boolean which we will set and unset
// when the game is running- or not.
private volatile boolean playing;
// Game is paused at the start
private boolean paused = true;
// A Canvas and a Paint object
private Canvas canvas;
private Paint paint;
// This variable tracks the game frame rate
private long fps;
// The city is built from bricks
private Brick[] bricks = new Brick[20000];
private int numBricks;
// Twinkling stars in the sky above the city
private Star[] stars = new Star[5000];
private int numStars;
// The player's ship
Ship player;
// The player's bullets
private Bullet[] playerBullets = new Bullet[10];
private int nextPlayerBullet;
private int maxPlayerBullets = 10;
// Our neat viewport/camera/clipping machine
Viewport vp;
private int metresToShowX;
private int metresToShowY;
private int numClipped;
// All code including HUD inner class goes here
// The constructor
public GameView(Context context, int screenX, int screenY) {
// The next line of code asks the
// SurfaceView class to set up our object.
// How kind.
super(context);
// Initialize ourHolder and paint objects
ourHolder = getHolder();
paint = new Paint();
// Initialize the Viewport
vp = new Viewport(screenX, screenY);
hud = new HUD(screenX, screenY);
// This SoundPool is deprecated but don't worry
soundPool = new SoundPool(10, AudioManager.STREAM_MUSIC,0);
try{
// Create objects of the 2 required classes
AssetManager assetManager = context.getAssets();
AssetFileDescriptor descriptor;
// Load our fx in memory ready for use
descriptor = assetManager.openFd("shoot.ogg");
shootID = soundPool.load(descriptor, 0);
descriptor = assetManager.openFd("damagebuilding.ogg");
damageBuildingID = soundPool.load(descriptor, 0);
}catch(IOException e){
// Print an error message to the console
Log.e("error", "failed to load sound files");
}
prepareLevel();
}
private void prepareLevel() {
player = new Ship();
// Initialize the playerBullets array
for (int i = 0; i < playerBullets.length; i++) {
playerBullets[i] = new Bullet();
}
//Reset the players location as the world centre of the viewport
//if game is playing
vp.setWorldCentre(player.getCentre().x, player.getCentre().y);
Random random = new Random();
int gapFromLastBuilding;
int maxGap = 25;
int buildingWidth;
int maxBuildingWidth = 10;
int buildingHeight;
int maxBuildingHeight = 85;
for (worldWidth = 0;
worldWidth < targetWorldWidth;
worldWidth += buildingWidth + gapFromLastBuilding) {
buildingWidth = random.nextInt(maxBuildingWidth) + 3;
buildingHeight = random.nextInt(maxBuildingHeight) + 1;
gapFromLastBuilding = random.nextInt(maxGap) + 1;
for (int x = 0; x < buildingWidth; x++) {
for (int y = groundLevel; y > groundLevel - buildingHeight; y--) {
boolean isLeft = false;
boolean isRight = false;
boolean isTop = false;
// Is this brick on left, right or top?
if (x == 0) {
isLeft = true;
}
if (x == buildingWidth - 1) {
isRight = true;
}
if (y == (groundLevel - buildingHeight) + 1) {
isTop = true;
}
bricks[numBricks] = new Brick(x + worldWidth, y,
isLeft, isRight, isTop);
numBricks++;
}
}
}
// Instantiate some stars
for (int i = 0; i < 500; i++) {
stars[i] = new Star(targetWorldWidth, targetWorldHeight);
numStars++;
}
}
@Override
public void run() {
while (playing) {
// Capture the current time in milliseconds in startFrameTime
long startFrameTime = System.currentTimeMillis();
// Update the frame
if (!paused) {
update();
}
// Draw the frame
draw();
// Calculate the fps this frame
// We can then use the result to
// time animations and more.
long timeThisFrame = System.currentTimeMillis() - startFrameTime;
if (timeThisFrame >= 1) {
fps = 1000/timeThisFrame;
}
}
}
private void update() {
//Reset the players location as the world centre of the viewport
//if game is playing
vp.setWorldCentre(player.getCentre().x, player.getCentre().y);
// Clip all off screen bricks
for (int i = 0; i < numBricks; i++) {
if (vp.clipObjects(bricks[i].getRect().left,
bricks[i].getRect().top, 1, 1)) {
bricks[i].clip();
} else {
bricks[i].unClip();
}
}
player.update(fps);
// Update all the player bullets if active
for (int i = 0; i < playerBullets.length; i++) {
if (playerBullets[i].getStatus()) {
playerBullets[i].update(fps);
}
}
// Have the player's bullets hit a building?
// Update all the player bullets if active
for (int i = 0; i < maxPlayerBullets; i++) {
if (playerBullets[i].getStatus()) {
for (int j = 0; j < numBricks; j++) {
if (!bricks[j].isClipped()) {
// Only process this brick if not destroyed
if(!bricks[j].isDestroyed()) {
if (bricks[j].getRect().contains(
playerBullets[i].getPoint().x,
playerBullets[i].getPoint().y)) {
playerBullets[i].setInactive();
soundPool.play(damageBuildingID, 1, 1, 0, 0, 1);
bricks[j].destroy();
int chainReactionSize = random.nextInt(6);
for(int k = 1; k < chainReactionSize; k++){
bricks[j+k].destroy();
bricks[j-k].destroy();
}
}
}
}
}
}
}
// set bullets inactive when they go out of view
// Clip all off screen bricks
for (int i = 0; i < maxPlayerBullets; i++) {
if (playerBullets[i].getStatus()) {
if(playerBullets[i].getPoint().x < 0){
playerBullets[i].setInactive();
}
else if(playerBullets[i].getPoint().x > targetWorldWidth){
playerBullets[i].setInactive();
}
else if(playerBullets[i].getPoint().y < 0){
playerBullets[i].setInactive();
}
else if(playerBullets[i].getPoint().y > targetWorldHeight){
playerBullets[i].setInactive();
}
}
}
// Update the stars
for (int i = 0; i < numStars; i++) {
stars[i].update();
}
// Update the bricks
for (int i = 0; i < numBricks; i++) {
if (!bricks[i].isClipped()) {
bricks[i].update();
}
}
// Has the ship collided with a top, left or right brick?
// that isn't destroyed
for (int i = 0; i < numBricks; i++) {
if (!bricks[i].isClipped() && !bricks[i].isDestroyed()) {
if (bricks[i].getRect().contains(player.getA().x, player.getA().y) ||
bricks[i].getRect().contains(player.getB().x, player.getB().y) ||
bricks[i].getRect().contains(player.getC().x, player.getC().y)) {
player.bump();
}
}
}
// Has the ship collided with the floor?
if (player.getA().y > groundLevel ||
player.getB().y > groundLevel ||
player.getC().y > groundLevel) {
player.bump();
}
// Has the ship collided with the game world ceiling?
if (player.getA().y < 0 ||
player.getB().y < 0 ||
player.getC().y < 0) {
player.bump();
}
// Has the ship collided with the game world left?
if (player.getA().x < 0 ||
player.getB().x < 0 ||
player.getC().x < 0) {
player.bump();
}
// Has the ship collided with the game world right?
if (player.getA().x > worldWidth ||
player.getB().x > worldWidth ||
player.getC().x > worldWidth) {
player.bump();
}
}
private void draw() {
// Make sure our drawing surface is valid or we crash
if (ourHolder.getSurface().isValid()) {
// Lock the canvas ready to draw
canvas = ourHolder.lockCanvas();
// Draw the background color
//canvas.drawColor(Color.argb(255, 87, 73, 122));
canvas.drawColor(Color.argb(255, 0, 0, 0));
// Draw the game world ceiling
paint.setColor(Color.argb(255, 255, 255, 255));
convertedRect = vp.worldToScreen(
0,
0,
targetWorldWidth,
1
);
canvas.drawRect(convertedRect, paint);
// Draw the left game world barrier
convertedRect = vp.worldToScreen(
0,
0,
1,
targetWorldHeight
);
canvas.drawRect(convertedRect, paint);
// Draw the right game world barrier
convertedRect = vp.worldToScreen(
targetWorldWidth,
0,
1,
targetWorldHeight
);
canvas.drawRect(convertedRect, paint);
// Draw stars if visible
// Update the stars
paint.setColor(Color.argb(255, 255, 255, 255));
for (int i = 0; i < numStars; i++) {
if (stars[i].getVisibility()) {
tempPointF = vp.worldToScreenPoint(stars[i].getX(), stars[i].getY());
canvas.drawPoint(tempPointF.x, tempPointF.y, paint);
}
}
// Draw the bricks if visible
for (int i = 0; i < numBricks; i++) {
if (!bricks[i].isClipped()) {
// Draw the bricks
// Choose the brush color for drawing
paint.setColor(bricks[i].getColor());
convertedRect = vp.worldToScreen(
bricks[i].getRect().left,
bricks[i].getRect().top,
bricks[i].getRect().right - bricks[i].getRect().left,
bricks[i].getRect().bottom - bricks[i].getRect().top
);
canvas.drawRect(convertedRect, paint);
// Draw building outline
// Choose the brush color for drawing
paint.setColor(Color.argb(255, 190, 190, 190));
if (bricks[i].getLeft()) {
canvas.drawLine(
convertedRect.left,
convertedRect.top,
convertedRect.left,
convertedRect.bottom,
paint
);
}
if (bricks[i].getRight()) {
canvas.drawLine(
convertedRect.right,
convertedRect.top,
convertedRect.right,
convertedRect.bottom,
paint
);
}
if (bricks[i].getTop()) {
canvas.drawLine(
convertedRect.left,
convertedRect.top,
convertedRect.right,
convertedRect.top,
paint
);
}
}
}
tempPointF = vp.worldToScreenPoint(player.getA().x, player.getA().y);
convertedPointA.x = tempPointF.x;
convertedPointA.y = tempPointF.y;
tempPointF = vp.worldToScreenPoint(player.getB().x, player.getB().y);
convertedPointB.x = tempPointF.x;
convertedPointB.y = tempPointF.y;
tempPointF = vp.worldToScreenPoint(player.getC().x, player.getC().y);
convertedPointC.x = tempPointF.x;
convertedPointC.y = tempPointF.y;
paint.setColor(Color.argb(255, 255, 255, 255));
canvas.drawLine(convertedPointA.x, convertedPointA.y,
convertedPointB.x, convertedPointB.y,
paint);
canvas.drawLine(convertedPointB.x, convertedPointB.y,
convertedPointC.x, convertedPointC.y,
paint);
canvas.drawLine(convertedPointC.x, convertedPointC.y,
convertedPointA.x, convertedPointA.y,
paint);
canvas.drawPoint(convertedPointA.x, convertedPointA.y, paint);
// Update all the player bullets if active
for (int i = 0; i < playerBullets.length; i++) {
if (playerBullets[i].getStatus()) {
tempPointF = vp.worldToScreenPoint(
playerBullets[i].getPoint().x, playerBullets[i].getPoint().y);
canvas.drawRect(tempPointF.x, tempPointF.y,
tempPointF.x+4,tempPointF.y+4, paint);
}
}
// Draw some debugging info
// Choose the brush color for drawing
paint.setColor(Color.argb(255, 255, 255, 255));
paint.setTextSize(20);
canvas.drawText("FPS = " + fps, 20, 70, paint);
// Draw the floor
convertedRect = vp.worldToScreen(
-10,
groundLevel,
targetWorldWidth + 10,
targetWorldHeight - groundLevel
);
paint.setColor(Color.argb(255, 5, 66, 9));
canvas.drawRect(convertedRect, paint);
// Change paint color
// Low alpha value to make buttons transparent
paint.setColor(Color.argb(80, 255, 255, 255));
for (Rect rect : hud.currentButtonList) {
RectF rf = new RectF(rect.left, rect.top, rect.right, rect.bottom);
canvas.drawRoundRect(rf, 15f, 15f, paint);
}
// Draw everything to the screen
ourHolder.unlockCanvasAndPost(canvas);
}
}
// If SpaceInvadersActivity is paused/stopped
// shutdown our thread.
public void pause() {
playing = false;
try {
gameThread.join();
} catch (InterruptedException e) {
Log.e("Error:", "joining thread");
}
}
// If SpaceInvadersActivity is started then
// start our thread.
public void resume() {
playing = true;
gameThread = new Thread(this);
gameThread.start();
}
// The SurfaceView class implements onTouchListener
// So we can override this method and detect screen touches.
@Override
public boolean onTouchEvent(MotionEvent motionEvent) {
hud.handleInput(motionEvent);
return true;
}
class HUD {
Rect left;
Rect right;
Rect thrust;
Rect shoot;
Rect pause;
//create an array of buttons for the draw method
public ArrayList<Rect> currentButtonList = new ArrayList<>();
HUD(int screenWidth, int screenHeight) {
//Configure the player buttons
int buttonWidth = screenWidth/8;
int buttonHeight = screenHeight/7;
int buttonPadding = screenWidth/80;
left = new Rect(buttonPadding,
screenHeight - buttonHeight - buttonPadding,
buttonWidth,
screenHeight - buttonPadding);
right = new Rect(buttonWidth + buttonPadding,
screenHeight - buttonHeight - buttonPadding,
buttonWidth + buttonPadding + buttonWidth,
screenHeight - buttonPadding);
thrust = new Rect(screenWidth - buttonWidth - buttonPadding,
screenHeight - buttonHeight - buttonPadding - buttonHeight - buttonPadding,
screenWidth - buttonPadding,
screenHeight - buttonPadding - buttonHeight - buttonPadding);
shoot = new Rect(screenWidth - buttonWidth - buttonPadding,
screenHeight - buttonHeight - buttonPadding,
screenWidth - buttonPadding,
screenHeight - buttonPadding);
pause = new Rect(screenWidth - buttonPadding - buttonWidth,
buttonPadding,
screenWidth - buttonPadding,
buttonPadding + buttonHeight);
// Add the rect objects in the same order as the static final values
currentButtonList.add(left);
currentButtonList.add(right);
currentButtonList.add(thrust);
currentButtonList.add(shoot);
currentButtonList.add(pause);
}
public void handleInput(MotionEvent motionEvent) {
int x = (int) motionEvent.getX(0);
int y = (int) motionEvent.getY(0);
switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
if (right.contains(x, y)) {
player.setMovementState(player.RIGHT);
} else if (left.contains(x, y)) {
player.setMovementState(player.LEFT);
} else if (thrust.contains(x, y)) {
player.setMovementState(player.THRUSTING);
} else if (shoot.contains(x, y)) {
playerBullets[nextPlayerBullet].shoot(
player.getA().x,player.getA().y, player.getFacingAngle());
nextPlayerBullet++;
if (nextPlayerBullet == maxPlayerBullets) {
nextPlayerBullet = 0;
}
soundPool.play(shootID, 1, 1, 0, 0, 1);
}else if(pause.contains(x, y)) {
paused = !paused;
}
break;
case MotionEvent.ACTION_UP:
player.setMovementState(player.STOPPING);
}
}
}// End of HUD
public void moveViewportRight(int maxWidth){
if(currentViewportWorldCentre.x < maxWidth - (metresToShowX/2)+3) {
currentViewportWorldCentre.x += 1;
}
}
public void moveViewportLeft(){
if(currentViewportWorldCentre.x > (metresToShowX/2)-3){
currentViewportWorldCentre.x -= 1;
}
}
public void moveViewportUp(){
if(currentViewportWorldCentre.y < (metresToShowY /2)-3) {
currentViewportWorldCentre.y -= 1;
}
}
public void moveViewportDown(int maxHeight){
if(currentViewportWorldCentre.y < maxHeight - (metresToShowY/2)+3) {
currentViewportWorldCentre.y += 1;
}
}
public int getNumClipped(){
return numClipped;
}
public void resetNumClipped(){
numClipped = 0;
}
// End of GameView
}