Archive for required library in project 'demo' cannot be read or is not a valid

getting issue : Archive for required library: '/home/user/.m2/repository/org/springframework/spring-core/5.3.9/spring-core-5.3.9.jar' in project 'demo' cannot be read or is not a valid ZIP file demo Build path Build Path Problem

Solution is respective jar is not downloaded correctly be either 

1.relaunch eclips

2.Goto path and delete respective directory so maven will fetch new one 

so above example 

goto /home/user/.m2/repository/org/springframework/spring-core/5.3.9/

and delete 5.3.9 dirctory.

Delete all the jar directory for which you are getting error

Dismiss keypad or keyboard in iphone

use

    [self.view endEditing:YES];

it will dismiss keypad

-iPhone backboardd[52] : failed to resume in time

Some times u are getting this error

Feb 27 13:18:45 -iPhone backboardd[52] <Warning>: com.xyz.abc failed to resume in time

Main cause for this is the load on main thread. 

Try to avoid calling blocking calls for long time on main thread.

Create separate threads for such things.

If u know steps to reproduce follow steps find load on main thread also 

find performSelectorOnMainThread function used and get called at the same time.

try to avoid call many performSelectorOnMainThread functions.

Which crates extra burden on main thread.

Moving from portrait view to Landscape view / Potrait UI orientation to landscape Ui orienttion in Phone iOS / Ui Orientation according to device Orientation / manually forcing orientation / change orientation manually

When u are switching from one view to another view .

First view is Portrait mode and next mode is in Landscape mode . 

Even u have implemented

-(BOOL)shouldAutorotate;

-(NSUInteger)supportedInterfaceOrientations;

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation duration:(NSTimeInterval)duration;

USe 

+ (void)attemptRotationToDeviceOrientation

Attempts to rotate all windows to the orientation of the device.

-(void) viewDidAppear:(BOOL)animated

{

    [UIViewController attemptRotationToDeviceOrientation];

    [super viewDidAppear:animated];

}