[英]Not sure why there is concurrent modification exception
I am iterating through two lists of Orb objects 我正在遍历两个Orb对象列表
Currently as I go through both lists I add and remove Orb objects as I iterate through them. 目前,当我浏览两个列表时,我在遍历它们时添加和删除了Orb对象。
//first I iterate through the "friendly" orb list.
for(orbIterator = friendlyOrbs.listIterator(); orbIterator.hasNext();) {
//I have only included what I (think) is the relevant code.
Orb tempOrb = orbIterator.next(); //Set a reference to the current orb object so I can update it and use its properties.
//Some drawing stuff I don't include.
//The orb is not dead
int orbResult = tempOrb.Update(); //Updates the orb object and returns its current state.
if(orbResult == 0) {
} else if(orbResult == 2) {
//Died a natural death
//Stuff to do when the orb dies naturally.
orbIterator.remove();
} else if(orbResult == 3) {
//Killed by player.
//stuff to do when player kills orb.
orbIterator.remove();
orbIterator.add(new Orb(...));
}
}
Now this is how I iterate through the "enemy" orb list: 现在,这就是我遍历“敌人”球列表的方式:
for(orbIterator = enemyOrbs.listIterator(); orbIterator.hasNext();) {
Orb tempOrb = orbIterator.next();
int orbResult = tempOrb.Update();
if(orbResult == 0) {
} else if (orbResult == 2) {
//Enemy orb died a natural death.
orbIterator.remove();
enemyOrbs.add(...);
} else if(orbResult == 3) {
//Enemy orb killed by player.
orbIterator.remove();
} else {
//Draw the orb.
}
}
I also have two timer tasks (one for spawning friendly orbs, one for spawning enemy orbs) that set a boolean flag that tells the onDraw method if it should add a new orb to the screen. 我还有两个计时器任务(一个用于生成友好的球,一个用于生成敌人的球),它们设置了一个布尔标志,该标志告诉onDraw方法是否应该向屏幕添加新的球。
//the friendly orb timertask
public static class FriendlyOrbTimerTask extends TimerTask implements Cloneable {
@Override
public void run() {
if(SystemClock.uptimeMillis() - drawCallTime < 100) {
Log.i("ADDING NEW ORB", "ADDING NEW ORB");
friendlyOrbToBeAdded = true;
friendlyOrbSpawnInterval += 250;
TIMER.schedule(this.clone(), friendlyOrbSpawnInterval);
} else {
pauseStartTime = SystemClock.uptimeMillis();
}
}
@Override
public FriendlyOrbTimerTask clone(){
return new FriendlyOrbTimerTask(); //add parameters from the current contextif needed.
}
}
Here is the enemyOrb timertask: 这是敌人的球计时器任务:
public static class EnemyOrbTimerTask extends TimerTask implements Cloneable {
@Override
public void run() {
if(SystemClock.uptimeMillis() - drawCallTime < 50) {
enemyOrbToBeAdded = true;
enemyOrbSpawnInterval+= 250;
TIMER.schedule(this.clone(), enemyOrbSpawnInterval);
}
}
@Override
public EnemyOrbTimerTask clone(){
return new EnemyOrbTimerTask(); //add parameters from the current contextif needed.
}
}
Here are the if statements that tell me if I should add a new orb to the screen (located in onDraw) 这是if语句,告诉我是否应在屏幕上添加新的球体(位于onDraw中)
//These are located right before I iterate through the lists.
if(friendlyOrbToBeAdded) {
friendlyOrbs.add(...);
friendlyOrbToBeAdded = false;
}
if(enemyOrbToBeAdded) {
enemyOrbs.add(...);
enemyOrbToBeAdded = false;
}
The problem is sometimes my app randomly crashes on the line that says: 问题是有时我的应用程序随机崩溃,并显示以下内容:
Orb tempOrb = orbIterator.next(); //This is in the enemyOrb iterator loop.
It gives the exception: java.util.ConcurrentModificationException
它给出了异常:
java.util.ConcurrentModificationException
I don't know why this is happening because I am using listIterator.add()
and listIterator.remove()
which should allow me to avoid these exceptions. 我不知道为什么会这样,因为我正在使用
listIterator.add()
和listIterator.remove()
,这应该允许我避免这些异常。
If your copy-pasting is accurate, then I think this is the problem: 如果您的复制粘贴正确,那么我认为这就是问题所在:
for(orbIterator = enemyOrbs.listIterator(); orbIterator.hasNext();) {
...
enemyOrbs.add(...);
...
}
You have a call to add
on the collection while you are iterating it. 在迭代集合时,您可以致电
add
集合。
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