Android 【很抱歉，xxx已停止】

當遇到【很抱歉，xxx已停止】時，查看LogCat，找Caused by那行會顯示甚麼原因跳出錯誤， 下面那行會顯示哪個檔的第幾行出錯(java:xx)，NullPointerException為常見空值錯誤， 此時用if或try catch來除錯
if else

if(someObject != null) {
    someObject.doSomething(); //錯誤行放裡面
} else {
   Log.i("Tag","空值"); // do something other
}

try catch

try {
    someObject.doSomething(); //錯誤行放裡面
} catch(NullPointerException e) {
    Log.i("Tag","空值"); // do something other
}

參考來源:http://stackoverflow.com/questions/2931065/how-to-handle-nullpointerexception-in-java