尝试catch异常总是返回null [英] try catch exception always returns null

问题描述

我有问题了Android。我开发的设备和有问题的捕捉异常。我跑了一些code在AsyncTask的最后简化到：

I got problem with Android. I develop on device and have problem with catching exceptions. I'm running some code in AsyncTask and finally simplified it to:

try
{
    if (true)
        throw new Exception("ERROR"); 
}      
catch (Exception e)
{    
    Log.e("e", "exception", e);
}

我的问题是，'E'变量总是空。不知道发生了什么实际。更重要的是它有时工作，但我不能说什么时候。我刚起床从电脑几分钟，回来的繁荣，它的工作原理。这样做的编码几分钟，这又是空......有对SO大约一年前，但没有人知回答一个问题。也许这时候会有人有一些想法。

My problem is that 'e' variable is always null. Not sure what's happening actually. What's more it sometimes works, but I can't say when. I just get up from computer for few minutes come back and boom, it works. Doing coding few minutes and again it's null... There was one question on SO about 1 year ago but noone known answer. Maybe this time someone will have some idea.

我觉得这有什么用的AsyncTask来做为它外面，我得到了异常正确逮住......仍然没有任何线索，为什么:(我发现它只是发生在debbuger相连。当我拿出电缆从设备，它实际上捕获和异常不为空了...

I think that it have something to do with AsyncTask as outside of it, I got exception catched properly... still don't have any clue why :( I found it only happens when debbuger is connected. When I take out cable from device it actually catches and exception isn't null anymore...

推荐答案

这是不可能有电子与在该点空值。如果您正在调试使用Eclipse你的应用程序，它会显示在该点的 e.toString（）值和 e.toString（）将返回空。

It's impossible to have e with null value at that point. If you are debugging your app using Eclipse, it will show the e.toString() value at that point and the e.toString() is returning null.

尝试其他的测试，使用这种code：

Try another test, using this code:

try {
    if (true) {
        throw new Exception("ERROR");
    } 
}      
catch (Exception e) {
    if (e == null) {
        Log.e("e", "e is really null!!!");
    }
    else {
        Log.e("e", "e is not null, toString is " + e + " and message is " + e.getMessage());
    }
}

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