我在宇宙飞船第一人称视角游戏中工作。我有一个操纵杆，当我移动操纵杆时，我可以移动屏幕上的所有物体（小行星），模拟用操纵杆移动宇宙飞船。
游戏运行正常，但现在我遇到了问题。如果您在最大左侧位置按下操纵杆，然后执行ACTION_UP，然后立即在操纵杆中立即执行ACTION_DOWN，但在最右侧位置，飞船开始以最大速度向右移动。 很难解释。例如，如果您在最左侧位置按下操纵杆，则太空船每帧向左移动-20px，如果您在最右侧位置按下操纵杆，则飞船向右移动+ 20px每帧。
所以，现在，如果我在操纵杆上进行快速最大左右最大触摸，那么宇宙飞船会做这个动作：-20 .... + 20
这不是真正的运动。
我想得到这个动作：-20 -17 -14 -9 -5 0 +5 +9 +14 +17 +20 ......我的意思是更加神奇的宇宙飞船运动。但问题是我不是数学或物理专家，我不知道如何在这个操纵杆中获得这种功能......任何帮助都将非常感激。
在这里，您可以使用操纵杆找到演示项目： https://mega.co.nz/#!cp5FhYIT!dM88qx_xQdyhED9fX_4xeJ9ciQYJirUlNzEi-KOzU2k
这是操纵杆代码，我在google中找到它，并且除了我之前描述的非逼真运动外，效果非常好：
public class Joystick extends View {
public static final int INVALID_POINTER = -1;
private JoystickMovedListener moveListener;
//# of pixels movement required between reporting to the listener
private float moveResolution;
//Max range of movement in user coordinate system
private float movementRange;
//Last touch point in view coordinates
private int pointerId = INVALID_POINTER;
private float touchX;
private float touchY;
private float touchXDelayedMovement;
private float touchYDelayedMovement;
//Handle center in view coordinates
private float handleX;
private float handleY;
//Last reported position in view coordinates (allows different reporting sensitivities)
private float reportX;
private float reportY;
//Center of the view in view coordinates
private int cX;
private int cY;
//Size of the view in view coordinates
private int dimX;
private int dimY;
private int innerPadding;
private int bgRadius;
private int handleRadius;
private int movementRadius;
private int handleInnerBoundaries;
//Cartesian coordinates of last touch point - joystick center is (0,0)
private int cartX;
private int cartY;
//User coordinates of last touch point
private int userX;
private int userY;
//Offset co-ordinates (used when touch events are received from parent's coordinate origin)
private int offsetX;
private int offsetY;
private Paint bgPaint;
private Paint handlePaint;
boolean disabled;
Handler handler;
Handler handlerDelayedMovement;
public Joystick(Context context) {
super(context);
initJoystickView();
}
private void initJoystickView() {
setFocusable(true);
handlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
handlePaint.setColor(Color.RED);
handlePaint.setStrokeWidth(1);
handlePaint.setStyle(Paint.Style.FILL_AND_STROKE);
bgPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
bgPaint.setColor(Color.DKGRAY);
bgPaint.setStrokeWidth(1);
bgPaint.setStyle(Paint.Style.FILL_AND_STROKE);
this.moveResolution = 1.0f;
handler = new Handler();
handlerDelayedMovement = new Handler();
}
public void setMovementRange(float movementRange) {
this.movementRange = movementRange;
}
public void setOnJostickMovedListener(JoystickMovedListener listener) {
this.moveListener = listener;
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
int d = Math.min(getMeasuredWidth(), getMeasuredHeight());
dimX = d;
dimY = d;
cX = d / 2;
cY = d / 2;
bgRadius = dimX/2 - innerPadding;
handleRadius = (int)(d * 0.2);
handleInnerBoundaries = handleRadius;
movementRadius = Math.min(cX, cY) - handleInnerBoundaries;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// Here we make sure that we have a perfect circle
int measuredWidth = measure(widthMeasureSpec);
int measuredHeight = measure(heightMeasureSpec);
setMeasuredDimension(measuredWidth, measuredHeight);
}
private int measure(int measureSpec) {
int result = 0;
// Decode the measurement specifications.
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.UNSPECIFIED) {
result = 200; // Return a default size of 200 if no bounds are specified.
} else {
result = specSize; // As you want to fill the available space always return the full available bounds.
}
return result;
}
@Override
protected void onDraw(Canvas canvas) {
canvas.save();
// Draw the background
canvas.drawCircle(cX, cY, bgRadius, bgPaint);
// Draw the handle
handleX = touchX + cX;
handleY = touchY + cY;
canvas.drawCircle(handleX, handleY, handleRadius, handlePaint);
canvas.restore();
}
public void setPointerId(int id) {
this.pointerId = id;
}
public int getPointerId() {
return pointerId;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_MOVE: {
if (disabled==true)
break;
return processMoveEvent(ev);
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP: {
if ( pointerId != INVALID_POINTER ) {
returnHandleToCenter();
returnHandleToCenterDelayedMovement();
setPointerId(INVALID_POINTER);
}
break;
}
case MotionEvent.ACTION_POINTER_UP: {
if ( pointerId != INVALID_POINTER ) {
final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if ( pointerId == this.pointerId ) {
returnHandleToCenter();
returnHandleToCenterDelayedMovement();
setPointerId(INVALID_POINTER);
return true;
}
}
break;
}
case MotionEvent.ACTION_DOWN: {
handlerDelayedMovement.removeCallbacksAndMessages(null);
if ( pointerId == INVALID_POINTER ) {
int x = (int) ev.getX();
if ( x >= offsetX && x < offsetX + dimX ) {
setPointerId(ev.getPointerId(0));
if (disabled==true){
return true;
}
return processMoveEvent(ev);
}
}
break;
}
case MotionEvent.ACTION_POINTER_DOWN: {
if ( pointerId == INVALID_POINTER ) {
final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
int x = (int) ev.getX(pointerId);
if ( x >= offsetX && x < offsetX + dimX ) {
setPointerId(pointerId);
return true;
}
}
break;
}
}
return false;
}
private boolean processMoveEvent(MotionEvent ev) {
if ( pointerId != INVALID_POINTER ) {
final int pointerIndex = ev.findPointerIndex(pointerId);
// Translate touch position to center of view
float x = ev.getX(pointerIndex);
touchX = x - cX - offsetX;
float y = ev.getY(pointerIndex);
touchY = y - cY - offsetY;
reportOnMoved();
invalidate();
return true;
}
return false;
}
private void reportOnMoved() {
//constraint circle
float diffX = touchX;
float diffY = touchY;
double radial = Math.sqrt((diffX*diffX) + (diffY*diffY));
if ( radial > movementRadius ) {
touchX = (int)((diffX / radial) * movementRadius);
touchY = (int)((diffY / radial) * movementRadius);
}
//We calc user coordinates
//First convert to cartesian coordinates
cartX = (int)(touchX / movementRadius * movementRange);
cartY = (int)(touchY / movementRadius * movementRange);
//Cartesian Coordinates
userX = cartX;
userY = cartY;
if (moveListener != null) {
boolean rx = Math.abs(touchX - reportX) >= moveResolution;
boolean ry = Math.abs(touchY - reportY) >= moveResolution;
if (rx || ry) {
this.reportX = touchX;
this.reportY = touchY;
moveListener.OnMoved(userX, userY);
}
}
}
private void reportOnMovedDelayedMovement() {
//constraint circle
float diffX = touchXDelayedMovement;
float diffY = touchYDelayedMovement;
double radial = Math.sqrt((diffX*diffX) + (diffY*diffY));
if ( radial > movementRadius ) {
touchXDelayedMovement = (int)((diffX / radial) * movementRadius);
touchYDelayedMovement = (int)((diffY / radial) * movementRadius);
}
//We calc user coordinates
//First convert to cartesian coordinates
cartX = (int)(touchXDelayedMovement / movementRadius * movementRange);
cartY = (int)(touchYDelayedMovement / movementRadius * movementRange);
//Cartesian Coordinates
userX = cartX;
userY = cartY;
if (moveListener != null) {
boolean rx = Math.abs(touchXDelayedMovement - reportX) >= moveResolution;
boolean ry = Math.abs(touchYDelayedMovement - reportY) >= moveResolution;
if (rx || ry) {
this.reportX = touchXDelayedMovement;
this.reportY = touchYDelayedMovement;
moveListener.OnMoved(userX, userY);
}
}
}
private void returnHandleToCenter() {
final int numberOfFrames = 5;
final double intervalsX = (0 - touchX) / numberOfFrames;
final double intervalsY = (0 - touchY) / numberOfFrames;
handler.removeCallbacksAndMessages(null);
for (int i = 0; i < numberOfFrames; i++) {
final int j = i;
handler.postDelayed(new Runnable() {
@Override
public void run() {
touchX += intervalsX;
touchY += intervalsY;
//reportOnMoved();
invalidate();
if (moveListener != null && j == numberOfFrames - 1) {
moveListener.OnReturnedToCenter();
}
}
}, i * 10);
}
if (moveListener != null) {
moveListener.OnReleased();
}
}
private void returnHandleToCenterDelayedMovement() {
final int numberOfFrames = 25;
touchXDelayedMovement=touchX;
touchYDelayedMovement=touchY;
final double intervalsX = (0 - touchXDelayedMovement) / numberOfFrames;
final double intervalsY = (0 - touchYDelayedMovement) / numberOfFrames;
handlerDelayedMovement.removeCallbacksAndMessages(null);
for (int i = 0; i < numberOfFrames; i++) {
handlerDelayedMovement.postDelayed(new Runnable() {
@Override
public void run() {
touchXDelayedMovement += intervalsX;
touchYDelayedMovement += intervalsY;
reportOnMovedDelayedMovement();
}
}, i * 50);
}
}
public void setInnerPadding(int innerPadding){
this.innerPadding=innerPadding;
}
public void disable(){
disabled=true;
}
public void enable(){
disabled=false;
}
public interface JoystickMovedListener {
public void OnMoved(int pan, int tilt);
public void OnReleased();
public void OnReturnedToCenter();
}
}
您必须在将使用操纵杆的类中执行此操作：
private JoystickMovedListener joystickListener = new JoystickMovedListener() {
@Override
public void OnMoved(int pan, int tilt) {
//here i move the objects in the game
}
}
@Override
public void OnReleased() {}
public void OnReturnedToCenter() {};
};
joystickOnScreen = new Joystick(this);
joystickOnScreen.setMovementRange(screenHeight/50);
joystickOnScreen.setInnerPadding(screenHeight/30);
joystickOnScreen.setOnJostickMovedListener(joystickListener);
RelativeLayout.LayoutParams joystickParams = new RelativeLayout.LayoutParams(sh/3, sh/3);
joystickParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
joystickParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
joystickParams.setMargins(sh/100, 0, 0, sh/100);
joystickOnScreen.setLayoutParams(joystickParams);
joystickOnScreen.setAlpha(0.3f);
答案 0 :(得分：1)
我不会为您实施这些更改，但希望这个答案可以帮助您自己实现这些更改。
使用当前实现，您将更新每帧的对象位置（x，y）。为了获得您想要的更逼真的物理效果，您还需要存储和更新速度（vx，vy）。
在当前正在更新位置的对象中添加两个新变量vx和vy（初始值为零）。操纵杆应控制速度的变化而不是位置。更改更新位置x和y的代码，以更新速度vx和vy。当操纵杆最大化时，您可以设置vx = vx - 3。
更新速度后，您需要使用速度变量更新位置。例如，设置位置x = x + vx。理想情况下，即使您不移动操纵杆，您也希望以不同的方式运行，但为了保持简单，您可以在更新速度变量后立即执行此更新。
通过这种实现，您将获得更逼真的游戏物理。作为下一步，您可能希望增加速度限制，以避免移动太快。这可以通过if语句来完成，在if语句中，在向其添加更多值之前检查值是否太大，或者在从中减去之前检查该值是否太小。祝你好运！