Tag Archives: API

Recompile with -Xlint in Android studio

3 Replies

Staying out of deprecated methods is useful, so your app won’t run in some compatibility mode on the device. Plus having clean build output is also nice 🙂

While building an app, Gradle may produces some warnings telling you that some input files are using unchecked or unsafe operations or they are overriding a deprecated API.

Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.

As the message suggest, we should recompile with -Xlint to get more details about the warnings.

In the app level build.gradle file

app level build.gradle file

we should add a section labelled  allprojects{}(if not already present).

In the allprojects{} section we will instruct Gradle to apply custom compiler arguments for each task involving  Java code compilation.

allprojects {
    tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xlint:unchecked" << "-Xlint:deprecation"
    }
}

Now each time we build our app we will get detailed output of the unchecked or unsafe operations and the deprecated API we are using.

Tip: if for some reason we want to continue using a deprecated API and just suppress the warnings, we could annotate the deprecated method with the

@SuppressWarnings("deprecation")

annotation.

CLastError

1 Reply

Small class for resolving and presenting in user readable form the codes from ::GetLastError() Win32 API function. The class has 2 static methods:

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void CLastError::Get( const DWORD& dwErrorCode, CString& strErrMessage )
{
	LPTSTR lpErrorText = NULL;
 
	::FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER, 
		0, dwErrorCode, 0, lpErrorText, MAX_PATH, 0 );
 
	strErrMessage = lpErrorText;
	::LocalFree( lpErrorText );
}

The ‘Get’ method supplied an error code will resolve the code to user readable error message and store it in the supplied ‘strErrMessage’ string!

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void CLastError::Show( const DWORD& dwErrorCode, const CString& strAppName )
{
	CString strErrMessage;
	Get( dwErrorCode, strErrMessage );
 
	CString strDisplayError;
	strDisplayError.Format( 
		_T("%s encountered an error and needs to close!\n\nError was: %s"),
		strAppName, strErrMessage );
 
	AfxMessageBox( strDisplayError, MB_ICONERROR | MB_OK );
}

The ‘Show’ method supplied an error code will resolve the code to user readable error message and the message will be displayed to the user trough AfxMessageBox() function.

Class declaration:

class CLastError
{
public:
 
	CLastError( );
	virtual ~CLastError( );
 
public:
 
	static void Get( const DWORD& dwErrorCode, CString& strErrMessage );
	static void Show( const DWORD& dwErrorCode, const CString& strAppName );
};

Class implementation:

CLastError::CLastError( )
{
}
 
CLastError::~CLastError( )
{
}
 
void CLastError::Get( const DWORD& dwErrorCode, CString& strErrMessage )
{
	LPTSTR lpErrorText = NULL;
 
	::FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER, 
		0, dwErrorCode, 0, lpErrorText, MAX_PATH, 0 );
 
	strErrMessage = lpErrorText;
	::LocalFree( lpErrorText );
}
 
void CLastError::Show( const DWORD& dwErrorCode, const CString& strAppName )
{
	CString strErrMessage;
	Get( dwErrorCode, strErrMessage );
 
	CString strDisplayError;
	strDisplayError.Format( 
		_T("%s encountered an error and needs to close!\n\nError was: %s"),
		strAppName, strErrMessage );
 
	AfxMessageBox( strDisplayError, MB_ICONERROR | MB_OK );
}