运行在单独进程中的ContentProvider

ContentProvider既可以与调用方处在同一进程，也可以运行在单独进程中，完全取决于ContentProvider所处的aplication的进程信息。因此假如ContentProvider运行在单独的进程中，那么调用ContentProvider将会涉及到IPC通信。

既然涉及到IPC通信，那么ContentProvider一定继承自IInterface，这个IInterface就是IContentProvider，其主要的接口方法如下，

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1. public IBulkCursor bulkQuery(Uri url, String[] projection,  
2.         String selection, String[] selectionArgs, String sortOrder, IContentObserver observer,  
3.         CursorWindow window) throws RemoteException;  
4. public Cursor query(Uri url, String[] projection, String selection,  
5.         String[] selectionArgs, String sortOrder) throws RemoteException;  
6. public String getType(Uri url) throws RemoteException;  
7. public Uri insert(Uri url, ContentValues initialValues)  
8.         throws RemoteException;  
9. public int bulkInsert(Uri url, ContentValues[] initialValues) throws RemoteException;  
10. public int delete(Uri url, String selection, String[] selectionArgs)  
11.         throws RemoteException;  
12. public int update(Uri url, ContentValues values, String selection,  
13.         String[] selectionArgs) throws RemoteException;  
14. public ParcelFileDescriptor openFile(Uri url, String mode)  
15.         throws RemoteException, FileNotFoundException;  
16. public AssetFileDescriptor openAssetFile(Uri url, String mode)  
17.         throws RemoteException, FileNotFoundException;  
18. public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations)  
19.         throws RemoteException, OperationApplicationException;  

public IBulkCursor bulkQuery(Uri url, String[] projection, String selection, String[] selectionArgs, String sortOrder, IContentObserver observer, CursorWindow window) throws RemoteException; public Cursor query(Uri url, String[] projection, String selection, String[] selectionArgs, String sortOrder) throws RemoteException; public String getType(Uri url) throws RemoteException; public Uri insert(Uri url, ContentValues initialValues) throws RemoteException; public int bulkInsert(Uri url, ContentValues[] initialValues) throws RemoteException; public int delete(Uri url, String selection, String[] selectionArgs) throws RemoteException; public int update(Uri url, ContentValues values, String selection, String[] selectionArgs) throws RemoteException; public ParcelFileDescriptor openFile(Uri url, String mode) throws RemoteException, FileNotFoundException; public AssetFileDescriptor openAssetFile(Uri url, String mode) throws RemoteException, FileNotFoundException; public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations) throws RemoteException, OperationApplicationException;
但是阅读ContentProvider代码时，会发现

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1. public abstract boolean onCreate();  
2. public void onConfigurationChanged(Configuration newConfig)；  
3. public void onLowMemory()；  

public abstract boolean onCreate();public void onConfigurationChanged(Configuration newConfig)；public void onLowMemory()；
这几个方法并不在IContentProvider中声明，因此千万注意它们在运行时并不是处在AndroidManifest.xml中声明时的进程中。而是处在调用ContentProvider的应用的进程中的。

因此千万不要在onCreate中添加你期望运行在ContentProvider的进程的代码。