为什么我会得到一个InvocationTargetException？Android 2D游戏
为什么我会得到一个InvocationTargetException？Android 2D游戏
提问于 2012-01-22 12:11:44
我正在用Cocos2D在安卓做一个2D游戏，用Java写的。以下是我的主要内容的代码：
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;
}正如您所看到的，这个函数看起来很好，canExecuteMovement中的矩形也非常好，但是在这一行中：
LINE 107: if (Rect.intersects(projectedBounds, platform[i].getBounds())) {我要买一台InvocationTargetException。下面是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)可能的问题是什么？guy中的getBounds()类如下所示：
public Rect getBounds() {
return new Rect(x, y, x+width, y+height);
}回答 1
Stack Overflow用户
回答已采纳
发布于 2012-01-22 12:43:04
InvocationTargetException只是动态调用中抛出的异常的包装器。真正的问题是它包装的NullPointerException：
Caused by: java.lang.NullPointerException
at com.qasim.platformer.GameLayer.canExecuteMovement(GameLayer.java:107)
at com.qasim.platformer.GameLayer.gameLoop(GameLayer.java:86)正如您所指出的，这是令人不快的一行：
if (Rect.intersects(projectedBounds, platform[i].getBounds())) {在此行中，空指针可能出现的唯一位置是platform[i].getBounds()。要么是platform本身是null，要么是platform[i]上的元素是。
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原文链接：
https://stackoverflow.com/questions/8958882
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