想知道是否有人能指出我正确的方向。
我希望能够将像子弹一样的对象从静态位置动画到屏幕上的任何区域。
我对简单的水平和垂直运动没有任何问题。即 x +/- 1 或 y +/- 1。但是当涉及到像子弹这样的物体时，它可以在任何程度上移动/动画，我不太确定如何通过使动画看起来平滑来做到这一点。例如，在 18、45 或 33 度角时，像 y+1、x+1、y+1 之类的算法......不会使动画非常流畅。
提前致谢
Ps 也许已经有一些文档了？
更新
感谢所有回复的人。
这是我迄今为止根据您的评论获得的代码。
package com.bullet;
//imports go here
public class canvas extends SurfaceView implements OnTouchListener, SurfaceHolder.Callback{
private Bitmap bullet;
private int bulletStartX, bulletStartY;
private int bulletX, bulletY;
private int bulletEndX = -1;
private int bulletEndY = -1;
private int incX = 0;
private int incY = 0;
private SurfaceHolder holder;
private Thread t;
public canvas(Context context) {
super(context);
this.setBackgroundColor(Color.WHITE);
setFocusable(true);
setFocusableInTouchMode(true);
setOnTouchListener(this);
bulletStartX = 0;
bulletStartY = 0;
bulletX = bulletStartX;
bulletY = bulletStartY;
bullet = BitmapFactory.decodeResource(getResources(), R.drawable.bullet);
holder = getHolder();
holder.addCallback(this);
}
public void onDraw(Canvas canvas){
if(bulletEndX != -1 && bulletEndY != -1){
Log.e("here", "drawing bullet");
Log.e("here", "x: " + bulletX + ", y: " + bulletY);
canvas.drawBitmap(bullet, bulletX, bulletY, null);
}
}
public void updateBullet(){
Log.e("here", "inc bullet");
bulletX += incX;
bulletY += incY;
if(bulletX > bulletEndX){
bulletEndX = -1;
}
if(bulletY > bulletEndY){
bulletEndY = -1;
}
}
@Override
public boolean onTouch(View v, MotionEvent event) {
int[] coordinates = {(int) event.getX(), (int) event.getY()};
int motion = event.getAction();
switch(motion){
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
break;
case MotionEvent.ACTION_UP:
bulletX = bulletStartX;
bulletY = bulletStartY;
bulletEndX = (int) event.getX();
bulletEndY = (int) event.getY();
incX = (int) bulletEndX / 50;
incY = (int) bulletEndY / 50;
Log.e("here", "touch up");
break;
}
return true;
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
t = new GameThread(this, holder);
t.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
//Thread class
class GameThread extends Thread{
private canvas canvas;
private SurfaceHolder holder;
private boolean run = false;
long delay = 70;
public GameThread(canvas canvas, SurfaceHolder holder){
this.holder = holder;
this.canvas = canvas;
startThread(true);
}
public boolean isRunning(){
return this.run;
}
private void startThread(boolean run){
this.run = run;
}
public void stopThread(){
this.run = false;
}
@Override
public void run(){
while(run){
Canvas c = null;
try {
//lock canvas so nothing else can use it
c = holder.lockCanvas(null);
synchronized (holder) {
//clear the screen with the black painter.
//This is where we draw the game engine.
//Log.e("drawthread", "running");
if(bulletEndX != -1 && bulletEndY != -1){
updateBullet();
canvas.postInvalidate();
}
canvas.onDraw(c);
//Log.e("drawthread", "ran");
try {
sleep(32);
//Log.e("slept", "sleeping");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
holder.unlockCanvasAndPost(c);
}
}
}
}
}
}
绘图效果很好，但是有两个问题。
1.绘图相当缓慢和跳跃......与这个java示例相比http://www.youtube.com/watch?v=-g5CyPQlIo4
2.如果点击是在接近 Y = 0 的位置，那么由于 ENDY / FRAME 的值小于 1，意味着向上舍入到 0 并且子弹穿过屏幕顶部，而不是Y 中的偶尔增量。
@SyntaxT3rr0r 你的权利，这可能是最好的方法。但是你知道任何实现这样的东西的文档吗？
再次感谢所有回复的人