Android异常 NullPointerException: Attempt to invoke virtual method int java.lang.Integer.intValue()
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异常详情
05-23 16:15:41.672 4206 6875 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference05-23 16:15:41.672 4206 6875 E AndroidRuntime: at org.libjingle.LibjingleWrapper$MessageEventHandler.handleMessage(LibjingleWrapper.java:310)05-23 16:15:41.672 4206 6875 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)05-23 16:15:41.672 4206 6875 E AndroidRuntime: at android.os.Looper.loop(Looper.java:142)05-23 16:15:41.672 4206 6875 E AndroidRuntime: at android.os.HandlerThread.run(HandlerThread.java:61)
相关代码
private static Map<String, Integer> downloadingFiles = null;...downloadingFiles.put(fileInfo.strFileName, msgId);...int msgid = downloadingFiles.get(serverFileName);
问题原因:
@1. 当serverFileName为null时,Map.get(Object key)会产生异常
java.lang.NullPointerException if the specified key is null and this map does not permit null keys (optional)
@2. 当downloadingFiles.get(serverFileName)为null时,会产生NullPointerException解决方法:
将如下代码int msgid = downloadingFiles.get(serverFileName);更改为:public int getId(String serverFileName) { if (null != serverFileName && downloadingFiles.containsKey(serverFileName)) { return downloadingFiles.get(serverFileName); } return 0; }
不要直接调用Map.get(Object key)方法,应该先判断Map.containsKey(String key)是否包含该字段,然后再从中取。
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