Getting Started with React Native

Brew Update

$brew update
$brew install node
$brew install watchman
$brew install yarn

$npm install -g react-native-cli

Init Project

$react-native init MyProject

$cd MyProject

$react-native run-ios

This will open up the Simulator but you can always open up Xcode manually

and show some fancy terminal window saying running on part 8081 blaa blaa 

Native means Xcode

$cd ios

$open MyProject.xcodeproj

Run the project and you might see following all over the debugger window !!!

 __nw_connection_get_connected_socket_block_invoke 50 Connection has no connected handler

1. Xcode menu -> Product -> Edit Scheme...
2. Environment Variables -> Add -> Name: "OS_ACTIVITY_MODE", Value:"disable"
3. Run your again

If every thing goes well you can run the project which shows the following screen.

Hello World!

"Welcome to React Native!" ... Seriously ? 

Some thing is very wrong about this window where is "Hello World!"

If you open the project folder you will see the following folder structure - 

You can open the index.ios.js file on any text editor of your choice, but as we are making a native app lets open it in Xcode itself ! 

Drag and drop the file in Currently open Xcode project but make sure you uncheck both 

 - Copy Items if needed  &

-  Add to target

Now open the file and navigate to line sweet 16 ! 

render() {

    return (

      <View style={styles.container}>

        <Text style={styles.welcome}>

            Hello World!

        </Text>

        <Text style={styles.instructions}>

          To get started, edit index.ios.js

        </Text>

        <Text style={styles.instructions}>

          Press Cmd+R to reload,{'\n'}

          Cmd+D or shake for dev menu

        </Text>

      </View>

    );

  }

Just replace the Line 20 with Hello World!

Now you do NOT need to hit "Cmd+R" on Xcode, just open the Simulator and hit "Cmd+R"

and with just small flicker for microsecond what you see is new content ! 

WoW !!! Thats the beauty of React Native - No compiling of code just reloading the view.

Note - don’t close the Terminal window; just keep it running in the background. If you do close it by mistake, simply stop and re-run the project via Xcode.

Links - 

https://github.com/facebook/react-native

https://facebook.github.io/react-native/docs/getting-started.html

https://facebook.github.io/react-native/

https://github.com/facebook/react-native/issues/10027

http://stackoverflow.com/questions/41311039/react-native-build-warning-issue

https://www.raywenderlich.com/126063/react-native-tutorial

Swift 2.0 Strings

After functional coding I feel the biggest change from Obj-C world to Swift was in support of Unicode string.

Then again the huge change from Swift 1.2 to Swift 2.0 might be in String.
In someway its a dramatic change !
As stated in Swift Blog

Swift provides a performant, Unicode-compliant string implementation as part of its Standard Library. In Swift 2, theString type no longer conforms to the CollectionType protocol, where String was previously a collection of Character values, similar to an array. Now, String provides a characters property that exposes a character collection view.

var letters: [Character] = ["c", "a", "f", "e"]
var string: String = String(letters)

print(letters.count) // 4
print(string) // cafe
print(string.characters.count) // 4

let acuteAccent: Character = "\u{0301}" // ´ COMBINING ACUTE ACCENT' (U+0301)

string.append(acuteAccent)
print(string.characters.count) // 4
print(string.characters.last!) // é

https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/StringsAndCharacters.html

NOTE

Extended grapheme clusters can be composed of one or more Unicode scalars. This means that different characters—and different representations of the same character—can require different amounts of memory to store. Because of this, characters in Swift do not each take up the same amount of memory within a string’s representation. As a result, the number of characters in a string cannot be calculated without iterating through the string to determine its extended grapheme cluster boundaries. If you are working with particularly long string values, be aware that the count(_:) function must iterate over the Unicode scalars in the entire string in order to calculate an accurate character count for that string.

The character count returned by the count(_:) function is not always the same as the length property of an NSString that contains the same characters. The length of an NSString is based on the number of 16-bit code units within the string’s UTF-16 rpresentation and not the number of Unicode extended grapheme clusters within the string. To reflect this fact, the length property from NSString is called utf16Count when it is accessed on a Swift String value.

Reference - 

Swift Standard Library Reference.

Core Data Model Objects using Mogenerator

Download Mogenerator at http://rentzsch.github.io/mogenerator/

Download mogenerator 1.27or install via homebrew:$ brew install mogeneratorupgrading using homebrew:$ brew update && brew upgrade mogenerator

Terminal

mogenerator --model CoreData/Model.xcdatamodeld/Model.xcdatamodel --output-dir Model/Mogenerator --template-var arc=true

XCode

1. Select your XCDataModeld
2. Editor --> Add Model Version

Projects --> Targets

Editor -->  Add Build Phases

MODELS_DIR="BeerBrowser/DataModel"

DATA_MODEL_PACKAGE="$MODELS_DIR/Beers.xcdatamodeld"

CURRENT_VERSION=`/usr/libexec/PlistBuddy "$DATA_MODEL_PACKAGE/.xccurrentversion" -c 'print _XCCurrentVersionName'`

mogenerator --template-var arc=true --model "$DATA_MODEL_PACKAGE/$CURRENT_VERSION" --output-dir "$MODELS_DIR/"

Or Simply,

/usr/local/bin/mogenerator --model "${PROJECT_DIR}/KhabarSanchar/CoreData/Model.xcdatamodeld/Model.xcdatamodel" --output-dir "${PROJECT_DIR}/Model/Mogenerator" --template-var arc=true

Sources

https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man8/PlistBuddy.8.html

http://nsscreencast.com/episodes/12-importing-into-core-data

C++ beginers code for Objective-C Developers using XCode

Problem 1: Using CPP code show the use of If…Then…Else statement-using user input values.

Code

//

//  main.cpp

//  Hello World CPP

//

//  Created by Bishal Ghimire on 9/19/13.

//  Copyright (c) 2013 Bishal Ghimire. All rights reserved.

//

#include <iostream>

using namespace std;

/**

   IF then else function for using user input values

*/

int main(int argc, const char * argv[]) {

    int inputAge;

    std::cout << "Input You Age, !\n";

    cin >> inputAge;

   

   

    if (inputAge >= 18) {

        cout << "You can Vote ! \n";

    }

    else if (inputAge < 18) {

        cout << "You can NOT vote ! \n";

    }

    return 0;

}

Output

$ g++ main.cpp

$ ./a.out

Input You Age, !

 29

You can Vote !

Problem 2: Using functions show how you can swipe variables using call by reference.

Code

/**

    Function to swipe two variables using third temp value

 */

void swap(int *u, int *v) {

    int temp;

    temp = *u;

    *u = *v;

    *v = temp;

    return;

}

int main(int argc, const char * argv[]) {

       

    int firstValue;

    cout<<"Input First Value \n";

    cin >> firstValue;

   

    int secondValue;

    cout<<"Input Second Value \n";

    cin >> secondValue;

   

    swap(firstValue, secondValue);

   

    cout<<"First Value and Second Value after they are Swaped \n";

    cout << "1st = " << firstValue << "\n2nd = " << secondValue;

    cout<<"\n";

    return 0;

}

Output

$ g++ main.cpp

$ ./a.out

Input First Value

12

Input Second Value

34

First Value and Second Value after they are Swaped

1st = 34

2nd = 12

Problem 3: Demonstrate the use of functional overloading in CPP (C++)

 Code

/**

  functionOverLoading.cpp

*/

#include "functionOverLoading.h"

using namespace std;

#define pi 3.141

/**

 Function overloading

 */

class fxn {

public:

    void area(int);              // circle

    void area(int, int);         // rectangle

    void area(int, int, int);    // triangle

};

void fxn::area(int a) {

    cout<<"Area of Circle: "<<pi*a*a;

    cout<<"\n";

}

void fxn::area(int a, int b) {

    cout<<"Area of rectangle: "<<a*b;

    cout<<"\n";

}

void fxn::area(int a, int b, int c) {

    // cout<<"Area of triangle: "<<a*b*c;

    cout<<"\n";

}

typedef enum ChoiceType

{

    choiceCircle    = 1,

    choiceRectangle,

    choiceTriangle,

    choiceExit

} ChoiceType;

int main(int argc, const char * argv[]) {

   

    int choice;

    int radius;

    int length;

    int breath;

    int sideA, sideB, sideC;

    fxn object;

   

    cout<<"\n\t\tFunction Overloading";

    cout<<"\n 1. Area of Circle \n 2. Area of Rectangle \n 3. Area of Triangle \n 4. Exit \n ";

    cout<<"Enter your Choice:";

    cin>>choice;

   

    switch (choice) {

        case choiceCircle:

            cout<<"Enter Radious of the Circle:";

            cin>>radius;

            object.area(radius);

            break;

        case choiceRectangle:

            cout<<"Enter Sides of Rectangle:";

            cin>>length>>breath;

            object.area(length, breath);

            break;

        case choiceTriangle:

            cout<<"Enter Sides of triangle:";

            cin>>sideA>>sideB>>sideC;

            object.area(sideA, sideB, sideC);

            break;

        case choiceExit:

            exit(0);

            break;

        default:

            break;

    }

    return 0;

}

Output 

$g++ functionOverLoading.cpp –o functionOverLoading

$ ./functionOverLoading

Function Overloading

 1. Area of Circle

 2. Area of Rectangle

 3. Area of Triangle

 4. Exit

 Enter your Choice:1

Enter Radious of the Circle:10

Area of Circle: 314.1

$ ./functionOverLoading

            Function Overloading

 1. Area of Circle

 2. Area of Rectangle

 3. Area of Triangle

 4. Exit

 Enter your Choice:2

Enter Sides of Rectangle:10 12

Area of rectangle: 120