Simple Coding Rules

1. Code should be proper indented.
2. Meaning full name of variables and constants.
3. Meaning full name of methods and classes.
4. No duplicate code.
5. No inline css.
6. No inline java script.
7. Html, css and java script code also be indented.
8. No html code should come with java services.
9. If you find a code two times in a class than make a separate method using that code.
10. If you find same code in two or more classes than make a separate class using that code and use       that class.

AngularJs: order by filter

Use order by like this:

<tr ng-repeat="emp in empList | orderBy:joiningDate">
</tr>

Above code will show you emp list in ascending order of joining date.

<tr ng-repeat="emp in empList | orderBy:-joiningDate">
</tr>

You can see I used - (hyphen) in above code. Due to this hyphen employee list will show in descending order of joining date.

How to show alternate image if source image is not found?

A example is here

Phonegap/Cordova: Download file

To download file in cordova you have to add following plugins:

1. File
2. File System
3. File Transfer

And example is here:
var app = {
    // Application Constructor
    initialize: function() {
        this.bindEvents();
    },
    // Bind Event Listeners
    //
    // Bind any events that are required on startup. Common events are:
    // 'load', 'deviceready', 'offline', and 'online'.
    bindEvents: function() {
        document.addEventListener('deviceready', this.onDeviceReady, false);
    },
    // deviceready Event Handler
    //
    // The scope of 'this' is the event. In order to call the 'receivedEvent'
    // function, we must explicitly call 'app.receivedEvent(...);'
    onDeviceReady: function() {
        app.receivedEvent('deviceready');
    },
    // Update DOM on a Received Event
    receivedEvent: function(id) {
        var parentElement = document.getElementById(id);
        var listeningElement = parentElement.querySelector('.listening');
        var receivedElement = parentElement.querySelector('.received');

        listeningElement.setAttribute('style', 'display:none;');
        receivedElement.setAttribute('style', 'display:block;');
window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, app.fileSystemSuccess, app.fileSystemFail);
        console.log('Received Event: ' + id);
    },

fileSystemSuccess: function(fileSystem) {
var directoryEntry = fileSystem.root;
directoryEntry.getDirectory("folder_rahul", {create: true, exclusive: false}, app.onDirectorySuccess, app.onDirectoryFail);
var rootdir = fileSystem.root;
var fp = rootdir.toURL();
alert(fp);
fp = fp + "folder_rahul/120px-State-lib-sum.png";
var fileTransfer = new FileTransfer();
   fileTransfer.download("http://data-gov.tw.rpi.edu/w/images/thumb/b/b1/State-lib-sum.png/120px-State-lib-sum.png",fp,
   function(entry) {
       alert("download complete: " + entry.fullPath);
   },
   function(error) {
cosnole.log(error);
       alert("download error source " + error.source);
       alert("download error target " + error.target);
       alert("upload error code" + error.code);
   }
);
},

fileSystemFail: function(evt) {
    alert("Failed---"+evt.target.error.code);
},

onDirectorySuccess: function(parent) {
console.log(parent);
},

onDirectoryFail: function(error) {
alert("Unable to create new directory: " + error.code);
}
};

More details are here and here

Angularjs filtered array length

In this example, I am applying a filter on list and after that I am getting the length.

<tr ng-show="showdate && (yourlist | filter:searchEmp).length > 0"><td class='appointment_header' style="font-weight:bold;" colspan="3"><span> {{----}}</span></td></tr>

Is it valid to replace http:// with // in a script src=“http://…”?

Yes, It is valid and good.

We don't have to think about protocol It can be http or https.

It is very helpful when we use CDN or any Google/Facebook or any other API.

Load javascript file dynamically using jquery with callback

Que: How to load javascript file dynamically using jquery?

Ans: jQuery.getScript("/xyz/abc/your.js", function(){

initialize(); // this function will call after loading of your.js

});

Solved: Android uninstall APK file from command line

Que: How to uninstall APK file from command line?

Ans: ./adb uninstall com.example.hello

"com.example.hello" this is the package name of your application.

Select2 get value and label of selected option

Que: How to get the value and label of option from select2 using jQuery?

Ans:

var theID = jQuery("#tags").select2('data').id;
var theSelection = jQuery("#tags").select2('data').text;

Here #tags is the id of your select2 field in html code. 

Solved:: Phonegap access origin problem with angularjs

I am giving simple steps to solve Phonegap access origin problem with angularjs

You have to create a filter at your java server side to allow cross domain requests (If your angularjs requests resources from any other java server):


A. Your java filter class will be look like as:
package com.abc.security.corsfilter.util;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class CORSFilter implements Filter {
    public void destroy() {
    }

    public static String VALID_METHODS = "DELETE, HEAD, GET, OPTIONS, POST, PUT";

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException,
            IOException {
        HttpServletRequest httpReq = (HttpServletRequest) req;
        HttpServletResponse httpResp = (HttpServletResponse) resp;

        // No Origin header present means this is not a cross-domain request
        String origin = httpReq.getHeader("Origin");
        if (origin == null) {
            // Return standard response if OPTIONS request w/o Origin header
            if ("OPTIONS".equalsIgnoreCase(httpReq.getMethod())) {
                httpResp.setHeader("Allow", VALID_METHODS);
                httpResp.setStatus(200);
                return;
            }
        } else {
            // This is a cross-domain request, add headers allowing access
            httpResp.setHeader("Access-Control-Allow-Origin", origin);
            httpResp.setHeader("Access-Control-Allow-Methods", VALID_METHODS);

            String headers = httpReq.getHeader("Access-Control-Request-Headers");
            if (headers != null)
                httpResp.setHeader("Access-Control-Allow-Headers", headers);

            // Allow caching cross-domain permission
            httpResp.setHeader("Access-Control-Max-Age", "3600");
        }
        // Pass request down the chain, except for OPTIONS
        if (!"OPTIONS".equalsIgnoreCase(httpReq.getMethod())) {
            chain.doFilter(req, resp);
        }
    }

    public void init(FilterConfig config) throws ServletException {

    }

}

B. Make entry of this filter in web.xml. Remember entry of this filter should be first, if you have any other filters entry in your web.xml

      <filter>
         <filter-name>CorsFilter</filter-name>
         <filter-class>com.certain.security.corsfilter.util.CORSFilter</filter-class>
     </filter>
     <filter-mapping>
         <filter-name>CorsFilter</filter-name>
         <url-pattern>/*</url-pattern>

     </filter-mapping>


*******Now we are going to make changes in code of your phonegap application.******


Your phonegap activity class should look like this:

package com.example.hello;

import android.os.Bundle;
import org.apache.cordova.*;
import android.webkit.CookieManager;

public class HelloWorld extends CordovaActivity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        super.init();
CookieManager.setAcceptFileSchemeCookies(true); // this must be in this class
        // Set by <content src="index.html" /> in config.xml
        super.loadUrl(Config.getStartUrl());
        //super.loadUrl("file:///index.html");
    }
}

Changes in /usr/local/src/node-v0.10.29/hello/config.xml

use <access origin="*" />