NAND: could not write file Error

Error:

NAND: could not write file /tmp/android-nipun/emulator-kOjnli, File exists

Solution:

The hard-disk partition which has /tmp folder had not enough space when the Android virtual device (AVD) was started. Making free space that is more than needed by AVD resolve this error.

How To Hide Status Bar In iOS 7

- (BOOL)prefersStatusBarHidden
{
   return YES;
}

Write above method on every UIViewController class which has a UIView to show without status bar.

A Code Snippet For Converting NSDate To NSString With NSDateFormatter

When working on programs that manipulate Dates sometimes those days need to be store & printed in particular format. iOS has given NSDate for date and time related data handling and  NSDateFormatter can be used to give a date of NSDate object a visual form. 

Code

Current Date and Time is obtained by init method of NSDate.

NSDate *date = [[NSDate alloc] init];

Create a NSDateFormatter for set the date format that is needed to print and get a NSString object from the date.

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

Use setDateFormat of NSDateFormatter to get a date format that is needed to display. This method get the required date format by using NSString parameter and returns nothing.  The method has been called on the object dateFormatter.

[dateFormatter setDateFormat:@"dd-MM-YYYY HH:mm:ss"];

Method signature for setDateFormat

- (void)setDateFormat:(NSString *)string

NSString *dateString = [dateFormatter stringFromDate:date];

Invoke stringFromDate on dateFormatter object to get the the date value of NSDate object in specified date format. This method consumes previously created date object and assign a NSString represent of the date on date object to dateString.

Method signature for stringFromDate

- (NSString *)stringFromDate:(NSDate *)date

Print the dateString using  NSLog();

NSLog(@"The Date: %@", dateString);

Complete Code

    NSDate *date = [[NSDate alloc] init];

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

    [dateFormatter setDateFormat:@"dd-MM-YYYY HH:mm:ss"];

    NSString *dateString = [dateFormatter stringFromDate:date];

    NSLog(@"The Date: %@", dateString);

CodeProject

isDescendantOfView: To check whether UIView is a subview of another UIView in iOS

Sometimes it's needed to check whether a UIView is a subview of another view. A typical use case is show and hide UIViews with button click events. it's better if the code check whether a UIView is a sub view of another view before the view is removed from the super view. UIView class have method  "isDescendantOfView" [1] it returns "YES" if the specified UIView is a subview of another UIView if it's not it returns "NO".

In example code below, "I m in" is printed if the theSubView is a sub view of the UIView self.view otherwise it prints "I m out".

if ([theSubView isDescendantOfView:self.view]) {

    

        NSLog(@"I m in");

        

    }else{

    

        NSLog(@"I m out");

    

    }

Reference:
[1]. http://developer.apple.com/library/ios/documentation/uikit/reference/uiview_class/uiview/uiview.html#//apple_ref/occ/instm/UIView/isDescendantOfView:

Converting NSString to NSData and NSData to NSString

Description

Below code segment shows how to convert a NSString value to NSData and NSData value to NSString value. At the beginning, It create a NSString literal with the variable name "firstString" then value of "firstString" variable is taken as a way that can be assigned into NSData variable by using method [1]. The variable "firstString" is assigned with "nil" in order to show that the variable contains nothing. The value of the variable has printed to by using "NSLog". After the printing a NSString object is created with by using previously created NSData. Method [2] has been used. Then the "firstString" value is printed again with NSLog.

1. - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding
2. - (instancetype)initWithData:(NSData *)data encoding:(NSStringEncoding)encoding

Code

    NSString *firstString = @"This is the string that is wanted to convert";

    

    NSData *dataFromString = [firstString dataUsingEncoding:NSUTF8StringEncoding];

    

    firstString = nil;

    

    NSLog(@"firstString (nil) = %@", firstString);

    

    firstString = [[NSString alloc] initWithData:dataFromString encoding:NSUTF8StringEncoding];

    

    NSLog(@"firstString (!nil) = %@", firstString);

Result

2014-03-24 17:10:11.367 TestProject[3048:60b] firstString (nil) = (null)

2014-03-24 17:10:11.369 TestProject[3048:60b] firstString (!nil) = This is the string that is wanted to convert