为什么我会收到一个的InvocationTargetException? Android的2D游戏 [英] Why am I getting an InvocationTargetException? Android 2D game
问题描述
我想提出一个2D游戏在Android中使用Cocos2D中,用Java编写的。这是我的code的主要的东西:
公共无效gameLoop(浮点DT){
//播放器重力
如果(canExecuteMovement(0,6)){
guy.moveY(6);
}
//播放器运动
如果(方向== 1){
如果(canExecuteMovement(-3,0))
guy.moveX(-3);
}否则,如果(方向== 2){
如果(canExecuteMovement(3,0))
guy.moveX(3);
}
}
私人布尔canExecuteMovement(INT的xChange,诠释yChange){
INT projectedX = guy.getBounds()左+的xChange。
INT projectedY = guy.getBounds()上衣+ yChange。
Log.i(DD,帅哥:+ guy.getBounds()的toString());
矩形projectedBounds =新的矩形(projectedX,projectedY,projectedX + guy.getWidth(),projectedY + guy.getHeight());
Log.i(DD,帅哥:+ projectedBounds.toString());
的for(int i = 0; I< platformCount;我++){
如果(Rect.intersects(projectedBounds,平台[I] .getBounds())){
返回false;
}
}
返回true;
}
正如你看到的,这个功能看起来蛮好的,在canExecuteMovement矩形是完全没关系,但是在这一行:
第107行:如果(Rect.intersects(projectedBounds,平台[I] .getBounds())){
我得到一个的InvocationTargetException。这里是logcat的:
01-21 23:10:12.601:W / System.err的(13118):java.lang.reflect.InvocationTargetException
01-21 23:10:12.601:W / System.err的(13118):在java.lang.reflect.Method.invokeNative(本机方法)
01-21 23:10:12.605:W / System.err的(13118):在java.lang.reflect.Method.invoke(Method.java:511)
01-21 23:10:12.605:W / System.err的(13118):在org.cocos2d.actions.CCTimer.update(CCTimer.java:82)
01-21 23:10:12.605:W / System.err的(13118):在org.cocos2d.actions.CCScheduler.tick(CCScheduler.java:253)
01-21 23:10:12.605:W / System.err的(13118):在org.cocos2d.nodes.CCDirector.drawCCScene(CCDirector.java:679)
01-21 23:10:12.605:W / System.err的(13118):在org.cocos2d.nodes.CCDirector.onDrawFrame(CCDirector.java:649)
01-21 23:10:12.605:W / System.err的(13118):在android.opengl.GLSurfaceView $ GLThread.guardedRun(GLSurfaceView.java:1462)
01-21 23:10:12.605:W / System.err的(13118):在android.opengl.GLSurfaceView $ GLThread.run(GLSurfaceView.java:1216)
01-21 23:10:12.605:W / System.err的(13118):显示java.lang.NullPointerException:产生的原因
01-21 23:10:12.608:W / System.err的(13118):在com.qasim.platformer.GameLayer.canExecuteMovement(GameLayer.java:107)
01-21 23:10:12.608:W / System.err的(13118):在com.qasim.platformer.GameLayer.gameLoop(GameLayer.java:86)
01-21 23:10:12.608:W / System.err的(13118):8 ...更多
01-21 23:10:12.620:D / dalvikvm(13118):GC_CONCURRENT释放460K,6%免费9279K / 9863K,暂停2MS + 3ms的
01-21 23:10:12.624:I / DD(13118):家伙:矩形(252,63 - 300,111)
可能是什么问题?的的getBounds()中的家伙类是这样的:
公共矩形的getBounds(){
返回新的矩形(X,Y,X +宽度,Y +高);
}
<一个href="http://docs.oracle.com/javase/7/docs/api/java/lang/reflect/InvocationTargetException.html"><$c$c>InvocationTargetException$c$c>只是一个包装,它是一个动态调用内抛出异常。真正的问题是<一个href="http://docs.oracle.com/javase/7/docs/api/java/lang/NullPointerException.html"><$c$c>NullPointerException$c$c> ,它的包装:
产生的原因:显示java.lang.NullPointerException
在com.qasim.platformer.GameLayer.canExecuteMovement(GameLayer.java:107)
在com.qasim.platformer.GameLayer.gameLoop(GameLayer.java:86)
正如您所指出的那样,这是有问题的行:
如果(Rect.intersects(projectedBounds,平台[I] .getBounds())){
一个空指针可能会发生在这条线的地方是在平台[I] .getBounds()
。无论是平台
自身空
或平台元素[I]
是
I am making a 2D game in Android with Cocos2D, written in Java. Here is my code for the main stuff:
public void gameLoop(float dt) {
//Player Gravity
if(canExecuteMovement(0, 6)) {
guy.moveY(6);
}
//Player Movement
if(direction == 1) {
if(canExecuteMovement(-3, 0))
guy.moveX(-3);
} else if(direction == 2) {
if(canExecuteMovement(3, 0))
guy.moveX(3);
}
}
private boolean canExecuteMovement(int xChange, int yChange) {
int projectedX = guy.getBounds().left + xChange;
int projectedY = guy.getBounds().top + yChange;
Log.i("DD", "guy:" + guy.getBounds().toString());
Rect projectedBounds = new Rect(projectedX, projectedY, projectedX + guy.getWidth(), projectedY + guy.getHeight());
Log.i("DD", "guy:" + projectedBounds.toString());
for (int i = 0; i < platformCount; i++) {
if (Rect.intersects(projectedBounds, platform[i].getBounds())) {
return false;
}
}
return true;
}
As you see, this function looks just fine, and the rectangles in canExecuteMovement are perfectly fine too, however in this line:
LINE 107: if (Rect.intersects(projectedBounds, platform[i].getBounds())) {
I am getting a InvocationTargetException. Here is the logcat:
01-21 23:10:12.601: W/System.err(13118): java.lang.reflect.InvocationTargetException
01-21 23:10:12.601: W/System.err(13118): at java.lang.reflect.Method.invokeNative(Native Method)
01-21 23:10:12.605: W/System.err(13118): at java.lang.reflect.Method.invoke(Method.java:511)
01-21 23:10:12.605: W/System.err(13118): at org.cocos2d.actions.CCTimer.update(CCTimer.java:82)
01-21 23:10:12.605: W/System.err(13118): at org.cocos2d.actions.CCScheduler.tick(CCScheduler.java:253)
01-21 23:10:12.605: W/System.err(13118): at org.cocos2d.nodes.CCDirector.drawCCScene(CCDirector.java:679)
01-21 23:10:12.605: W/System.err(13118): at org.cocos2d.nodes.CCDirector.onDrawFrame(CCDirector.java:649)
01-21 23:10:12.605: W/System.err(13118): at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1462)
01-21 23:10:12.605: W/System.err(13118): at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1216)
01-21 23:10:12.605: W/System.err(13118): Caused by: java.lang.NullPointerException
01-21 23:10:12.608: W/System.err(13118): at com.qasim.platformer.GameLayer.canExecuteMovement(GameLayer.java:107)
01-21 23:10:12.608: W/System.err(13118): at com.qasim.platformer.GameLayer.gameLoop(GameLayer.java:86)
01-21 23:10:12.608: W/System.err(13118): ... 8 more
01-21 23:10:12.620: D/dalvikvm(13118): GC_CONCURRENT freed 460K, 6% free 9279K/9863K, paused 2ms+3ms
01-21 23:10:12.624: I/DD(13118): guy:Rect(252, 63 - 300, 111)
What could be the problem? the getBounds() class in guy is this:
public Rect getBounds() {
return new Rect(x, y, x+width, y+height);
}
InvocationTargetException
is just a wrapper for an exception that's thrown within a dynamic invocation. The true problem is the NullPointerException
that it's wrapping:
Caused by: java.lang.NullPointerException
at com.qasim.platformer.GameLayer.canExecuteMovement(GameLayer.java:107)
at com.qasim.platformer.GameLayer.gameLoop(GameLayer.java:86)
As you've pointed out, this is the offending line:
if (Rect.intersects(projectedBounds, platform[i].getBounds())) {
The only place a null pointer could be happening on this line is at platform[i].getBounds()
. Either platform
itself is null
, or the element at platform[i]
is.
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