(Android) How to resolve the exception of "Table has not been deactivated or closed"

I'm working on the migration my project from M5 to 0.9, i got some exceptions of SQLite which shows "Table/Cursor has not been deactivated or closed" in my database class, i found the problems come from the Cursor. After read the API documents, i understand each opened Cursor should be deactivated and closed after reading its content. Here is an example:

Cursor cursor = sqlite.query(table, null, selection, null, null, null, null);
if (cursor.getCount() > 0){
int cursorCount = cursor.getCount();
ArrayList records = new ArrayList();
cursor.moveToFirst();
for (int i=0; i record = new HashMap();
String[] columns = cursor.getColumnNames();
int columnsNb = columns.length;
for (int column=0; column

(Objective-C) How to block thread

In the multi-threading programming, sometimes we need block the other threads to wait the result of a thread. There are several solutions:

1. Using @synchronized. With this solution, we don't create a NSThread object, here is an example:

- (void) callThreadMethod {
@synchronized(self) {
//the methods you want the thread to do
}
}

2. Using NSLock. Still don't create NSThread object, here is an example:

- (void) callThreadMethod {
NSLock *myLock = [[NSLock alloc] init];
[myLock lock];
//the methods you want the thread to do
[myLock unlock];
}

For the other solutions, you could read this great tutorial of multi-threading, Multithreading Tutorial

(iPhone) How to use Preference

Writing a simple data to preference:

CFStringRef textColorKey = CFSTR("defaultTextColor");
CFStringRef colorBLUE = CFSTR("BLUE");
// Set up the preference.
CFPreferencesSetAppValue(textColorKey, colorBLUE,
kCFPreferencesCurrentApplication);
// Write out the preference data.
CFPreferencesAppSynchronize(kCFPreferencesCurrentApplication);

Reading a simple data from preference:

CFStringRef textColorKey = CFSTR("defaultTextColor");
CFStringRef textColor;
// Read the preference.
textColor = (CFStringRef)CFPreferencesCopyAppValue(textColorKey,
kCFPreferencesCurrentApplication);
// When finished with value, you must release it
// CFRelease(textColor);

To replace the exist key's value, just overwrite the values of key.

(Objective-C) Convert between NSString and CFStringRef

From NSString to CFStringRef:
NSString *test = @"test";
CFStringRef testCF = (CFStringRef) test;


From CFStringRef to NSString:
CFStringRef testCF = "test";
NSString *test = (NSString *) testCF;

End of student life

I just passed the presentation of my internship in Penbase, this means my student life is over, i finished my education of university, i am going to start the professional life.