I’m currently writing an application for the Android platform that requires a mounted SD card (or ExternalStorage). I know that it might not be the best way to require something like that, but the application will work with quite a lot of data, and I don’t even want to think about storing that on the device’s storage.
Anyway, to ensure that the application won’t run without the external storage, I do a quick check in the activity’s onCreate method. If the card is not mounted, I want to display an error message and then quit the application.
My current approach looks like this:
public void onCreate ( Bundle savedInstanceState )
{
super.onCreate( savedInstanceState );
setContentView( R.layout.main );
try
{
// initialize data storage
// will raise an exception if it fails, or the SD card is not mounted
// ...
}
catch ( Exception e )
{
AlertDialog.Builder builder = new AlertDialog.Builder( this );
builder
.setMessage( "There was an error: " + e.getMessage() )
.setCancelable( false )
.setNeutralButton( "Ok.", new DialogInterface.OnClickListener()
{
public void onClick ( DialogInterface dialog, int which )
{
MyApplication.this.finish();
}
} );
AlertDialog error = builder.create();
error.show();
return;
}
// continue ...
}
When I run the application, and the exception gets raised (I raise it manually to check if everything works), the error message is displayed correctly. However when I press the button, the application closes and I get an Android error, that the application was closed unexpectedly (and I should force exit).
I read some topics before on closing an application, and I know that it maybe shouldn’t happen like that. But how should I instead prevent the application from continuing to run? How do you close the application correctly when an error occurs?
