我今天花了很多时间研究为什么我的吸气剂返回null并且似乎无法找到一个干净的答案。我希望使用类创建一个干净的层次结构，并将信息从一个传递到另一个。我不知道这是不是很好的做法，我仍然是游戏开发和Android工作室的新手。我希望能够从Game.java（这是我的活动类）传递变量，而不将其添加到其构造函数中的其他类。我希望能够访问getters，就像它是另一个类，但似乎无法弄清楚如何。完整代码将包含在下面：Game.java中的getXDirection和getyDirecion从播放器类返回0，暗示它们尚未初始化
game.Java
package com.Frenchie.SpaceshipSammy;
import ...
public class Game extends Activity implements SensorEventListener{
private SensorManager senSensorManager;
private Sensor senAccelerometer;
//Directional constants
private static final int DIRECTION_STATIONARY = 0;
private static final int DIRECTION_LEFT = 1;
private static final int DIRECTION_RIGHT= 2;
private static final int DIRECTION_UP = 3;
private static final int DIRECTION_DOWN= 4;
//Direction variables
private int yDirection, xDirection;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Set view to GameView
setContentView(new GameView(this));
//Sensor stuff
senSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
senAccelerometer = senSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
senSensorManager.registerListener(this, senAccelerometer , SensorManager.SENSOR_DELAY_GAME);
}
@Override
public boolean onTouchEvent(MotionEvent motionEvent) {
switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
//Finger down - Move up
yDirection = DIRECTION_UP;
break;
case MotionEvent.ACTION_UP:
//Finger lifted - Move down
yDirection = DIRECTION_DOWN;
break;
}
return true;
}
//Overriding Accelerometer to read data
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
Sensor mySensor = sensorEvent.sensor;
if (mySensor.getType() == Sensor.TYPE_ACCELEROMETER) {
float x = sensorEvent.values[1];
if (x > -1 && x < 1) {
//Stationary
xDirection = DIRECTION_STATIONARY;
} else if (x >= 1) {
//Move right
xDirection = DIRECTION_RIGHT;
} else if (x <= -1) {
//Move left
xDirection = DIRECTION_LEFT;
} else {
Log.d("onSensorChanged", "Escaped");
}
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
//Getters for Player class to use
public int getyDirection() {
return yDirection;
}
public int getxDirection() {
return xDirection;
}
}
player.Java
package com.Frenchie.SpaceshipSammy;
import ...
public class Player {
//Directional constants
private static final int DIRECTION_STATIONARY = 0;
private static final int DIRECTION_LEFT = 1;
private static final int DIRECTION_RIGHT = 2;
private static final int DIRECTION_UP = 3;
private static final int DIRECTION_DOWN = 4;
//Location variables
private int x, y, speed;
//Sprite
private Bitmap sprite;
private Game userInput;
public Player(Context context){
speed = 10;
userInput = new Game();
sprite = BitmapFactory.decodeResource(context.getResources(), R.drawable.player);
}
//Called from Logic to move players location
public void PositionUpdate(){
xMove();
yMove();
}
private void xMove(){
if (userInput.getxDirection() == DIRECTION_STATIONARY){
//Stationary
}
else if (userInput.getxDirection() == DIRECTION_RIGHT){
//Move right
x += speed;
Log.d("xMove","Right");
}
else if (userInput.getxDirection() == DIRECTION_LEFT){
//Move left
x -= speed;
}
else {
Log.d("xMove", "xDirection unrecognised");
}
}
private void yMove(){
if (userInput.getyDirection() == DIRECTION_UP){
//Move up
y -= speed;
}
else if (userInput.getyDirection() == DIRECTION_DOWN){
//Move down
y += speed;
}
else{
//Log.d("yMove", "yDirection unrecognised");
}
}
//Get x and y for Logic
public int getX() {
return x;
}
public int getY() {
return y;
}
public Bitmap getSprite() {
return sprite;
}
}
logic.Java
package com.Frenchie.SpaceshipSammy;
import ...
public class Logic implements Runnable {
//Bring in required classes
private Player player;
//Player variables
private int yPlayer, xPlayer;
private Bitmap playerSprite;
public Logic(Context context){
player = new Player(context);
//Sprite currently wont change so this doesn't need to be updated with the location
playerSprite = player.getSprite();
//Creating and running thread
Thread thread = new Thread(this);
thread.start();
}
//Thread to tell the players position update method to run and update the players values in this class
@Override
public void run() {
while(true) {
player.PositionUpdate();
PlayerLocation();
}
}
//Updates the players location which can be passed onto GameView
public void PlayerLocation(){
xPlayer = player.getX();
yPlayer = player.getY();
}
//Getters for GameView to use
public int getyPlayer() {
return yPlayer;
}
public int getxPlayer() {
return xPlayer;
}
public Bitmap getPlayerSprite() {
return playerSprite;
}
}
game view.Java
package com.Frenchie.SpaceshipSammy;
import ...
public class GameView extends SurfaceView implements Runnable{
private SurfaceHolder surfaceHolder = getHolder();
private Canvas canvas;
//Link Logic class
private Logic logic;
public GameView(Context context) {
super(context);
//Creates logic as a new object
logic = new Logic(context);
//Creates and starts the thread
Thread thread = new Thread(this);
thread.start();
}
//Override thread method. This is called when the thread is started
@Override
public void run() {
while (true){
DrawFrame();
}
}
private void DrawFrame(){
canvas = surfaceHolder.lockCanvas();
if (surfaceHolder.getSurface().isValid()){
canvas.drawColor(Color.MAGENTA);
canvas.drawBitmap(logic.getPlayerSprite(), logic.getxPlayer(), logic.getyPlayer(), null);
surfaceHolder.unlockCanvasAndPost(canvas);
} else {
Log.d("DrawFrame", "Surface Invalid");
}
}
}
所有帮助表示赞赏！
这是你的问题，在你的GameView
userInput = new Game();
您指向Activity的新实例，而不是显示的实际Activity。在使用活动实例“this”创建Player之后，您需要设置此值。