[英]Trying to read SMS/MMS on Android and geting java.lang.NullPointerException
I'm trying to read SMS/MMS on Android, and I have followed the answer , when writing the code and try to run it on an Android OS 6.0.1 on Samsung device I got the following exception:我正在尝试在 Android 上阅读 SMS/MMS,并且我遵循了答案,在编写代码并尝试在三星设备上的 Android OS 6.0.1 上运行它时,出现以下异常:
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.os.Parcel.readException(Parcel.java:1626)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:183)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:135)
at android.content.ContentProviderProxy.query(ContentProviderNative.java:421)
at android.content.ContentResolver.query(ContentResolver.java:502)
at android.content.ContentResolver.query(ContentResolver.java:445)
at com.my.code.services.ListenSmsMmsService$SMSObserver.onChange(ListenSmsMmsService.java:102)
This is the code that is creating the exception:这是创建异常的代码:
public void onChange(boolean selfChange) {
super.onChange(selfChange);
/*first of all we need to decide message is Text or MMS type.*/
final String[] projection = new String[] {"*"};
Uri mainUri = Telephony.MmsSms.CONTENT_CONVERSATIONS_URI; //URI for query
Cursor mainCursor = contentResolver.query(mainUri, projection, null, null, null);
The last line is the one that causes the crash.最后一行是导致崩溃的那一行。 even if I used:
即使我使用:
Uri mainUri = Uri.parse("content://mms-sms/conversations/");
and:和:
final String[] projection = new String[]{"_id", "ct_t"};
or:或者:
final String[] projection = new String[]{Telephony.MmsSms.TYPE_DISCRIMINATOR_COLUMN};
the crash happen.崩溃发生。
When I tried to run a query on ContactsContract.PhoneLookup.CONTENT_FILTER_URI
the query was successfull.当我尝试在
ContactsContract.PhoneLookup.CONTENT_FILTER_URI
上运行查询时,查询成功。
What can be the problem, that causes the crash?可能是什么问题,导致崩溃?
This happens on many other Samsung devices: seems that on these devices, you can't query for content://mms-sms/conversations?simple=true
without the ?simple=true
suffix - and when you add this suffix, it affects the returned columns, and that's why the projection failed.这发生在许多其他三星设备上:似乎在这些设备上,您无法在没有
?simple=true
后缀的情况下查询content://mms-sms/conversations?simple=true
- 当您添加此后缀时,它会影响返回的列,这就是投影失败的原因。
See here for more related info about this, though no one really knows why it behaves this way :(有关更多相关信息,请参见此处,尽管没有人真正知道它为什么会这样:(
There might be a workaround, using an undocumented URI of content://mms-sms/complete-conversations
- as you can read here .可能有一种解决方法,即使用
content://mms-sms/complete-conversations
的未记录 URI - 您可以在此处阅读。
I had the same problem with Samsung devices, so for just SMS conversations, I tried doing grouping by thread id on the SMS table here .我在三星设备上遇到了同样的问题,因此对于 SMS 对话,我尝试在此处按 SMS 表上的线程 id 进行分组。
Unfortunately content://mms-sms/complete-conversations
doesn't seem to aggregate on the thread id like content://mms-sms/conversations
does, so you end up with multiple messages from the same thread.不幸的是
content://mms-sms/complete-conversations
似乎不像content://mms-sms/conversations
那样聚合在线程 id 上,所以你最终会收到来自同一线程的多条消息。
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