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Java-填充ArrayList会产生空指针错误_Java_Nullpointerexception - Fatal编程技术网

Java-填充ArrayList会产生空指针错误

Java-填充ArrayList会产生空指针错误,java,nullpointerexception,Java,Nullpointerexception,在我的课堂上,我定义: private ArrayList<BlockObject> blocks; 但是我得到了这个错误 02-22 17:06:52.672: E/AndroidRuntime(479): Caused by: java.lang.NullPointerException 02-22 17:06:52.672: E/AndroidRuntime(479): at com.comp1008.hhh.uuu.Scenario.blocks(Scenario.jav

在我的课堂上,我定义:

private ArrayList<BlockObject> blocks;
但是我得到了这个错误

02-22 17:06:52.672: E/AndroidRuntime(479): Caused by: java.lang.NullPointerException
02-22 17:06:52.672: E/AndroidRuntime(479):  at com.comp1008.hhh.uuu.Scenario.blocks(Scenario.java:41)
有什么建议吗?

在填充arraylist之前,您必须初始化它

private ArrayList<BlockObject> blocks = new ArrayList<BlockObject>(); 
在填充arraylist之前,必须初始化它

private ArrayList<BlockObject> blocks = new ArrayList<BlockObject>(); 
你必须初始化你的对象


你必须初始化你的对象。

哦,天哪,那是非常快和非常容易的。我对这门语言还不熟悉,非常欣赏哦,伙计,这门语言非常快,非常简单。我是新来的语言,非常感谢
private ArrayList<BlockObject> blocks = new ArrayList<BlockObject>();