There is one injector per Angular application.  Normally you don&#39;t need to interact with it directly.  The injector is key to making dependency injection work in Angular.

Module methods such as `factory`, `service`, `directive`, etc. register these items with the injector.  When you inject something (e.g., a service into a controller), the injector will lookup and then instantiate the service (if it wasn&#39;t instantiated already -- if it was, it will return the already-instantiated object).

If for some reason you really needed to dynamically inject a service into, say, a controller, see https://stackoverflow.com/a/14418384/215945 for an example of how to do that.
See also https://stackoverflow.com/a/14743553/215945.


I&#39;m troubleshooting a bug with a service I call through .NET&#39;s HttpClient, trying to route the request through a local proxy (Fiddler), but my proxy settings seem to not be taking effect.

Here&#39;s how I create the client:

    private HttpClient CreateHttpClient(CommandContext ctx, string sid) {
        var cookies = new CookieContainer();

        var handler = new HttpClientHandler {
            CookieContainer = cookies,
            UseCookies = true,
            UseDefaultCredentials = false,
            Proxy = new WebProxy(&quot;http://localhost:8888&quot;, false, new string[]{}),
            UseProxy = true,
        };

        // snip out some irrelevant setting of authentication cookies

        var client = new HttpClient(handler) {
            BaseAddress = _prefServerBaseUrl,
        };

        client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue(&quot;application/json&quot;));

        return client;
    }

then I send the request by:

    var response = CreateHttpClient(ctx, sid).PostAsJsonAsync(&quot;api/prefs/&quot;, smp).Result;

Request goes straight to the server without attempting to hit the proxy.  What did I miss?


Using a proxy with .NET 4.5 HttpClient

I have a listview which is fetching data from sqlite database by Json.
    
I want to turn it into dynamic listview that at the end of scroll, a &quot;load more items&quot; appears in the footer of the list while loading more items and adding them to the adapter (for example 10 items each time). I have problem in implementing this feature. Please help me with it. Thanks.

    public class AllProductsActivity extends Activity {

	... defining variables...;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		new LoadAllProducts().execute();

	}
	
	class LoadAllProducts extends AsyncTask&lt;String, String, String&gt; {
	
		@Override
		protected void onPreExecute() {
			super.onPreExecute();
			... progress dialog...
		}

		protected String doInBackground(String... args) {
			countryList = new ArrayList&lt;Country&gt;();
			List&lt;NameValuePair&gt; params = new ArrayList&lt;NameValuePair&gt;();
			JSONObject json = jParser.makeHttpRequest(url_all_products, &quot;GET&quot;, params);

			Log.d(&quot;All Products: &quot;, json.toString());

			try {
				// Checking for SUCCESS TAG
				int success = json.getInt(TAG_SUCCESS);

				if (success == 1) {
					// products found
					// Getting Array of Products
					products = json.getJSONArray(TAG_PRODUCTS);

					// looping through All Products
					for (int i = 0; i &lt; products.length(); i++) {
						JSONObject c = products.getJSONObject(i);

						// Storing each json item in variable
						String id = c.getString(TAG_PID);
						String name = c.getString(TAG_NAME);
						String description = c.getString(TAG_DESCRIPTION);
						String due_date = c.getString(TAG_DUE_DATE);
						String staff = c.getString(TAG_STAFF);
						String status = c.getString(TAG_STATUS);

						country = new Country(id,name,description,
								due_date, staff, status);
						countryList.add(country);
					}
				}
			} catch (JSONException e) {
				e.printStackTrace();
			}

			return null;
		}

		protected void onPostExecute(String file_url) {
			pDialog.dismiss();
			runOnUiThread(new Runnable() {
				public void run() {

					displayListView();

				}
			});
		}
	}

	private void displayListView() {
		dataAdapter = new MyCustomAdapter(this,
				R.layout.country_info, countryList);
		ListView listView = (ListView) findViewById(R.id.listView1);
		listView.setAdapter(dataAdapter);
	}

	private class MyCustomAdapter extends ArrayAdapter&lt;Country&gt; {

		... blah blah blah ...

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {

			ViewHolder holder = null;
			Log.v(&quot;ConvertView&quot;, String.valueOf(position));
			if (convertView == null) {
			... blah blah blah ...
			}

			return convertView;
		}
	}
    }

dynamic listview adding &quot;Load more items&quot; at the end of scroll

Due to deficiency of official docs explanation on `$injector` (service) I have hard time understanding how it actually works. How many `$injector`s may be per application? When should I use it? How does `$injector` work? (and so on) Please provide me with a real world explanation and some JavaScript sandbox samples on it.

Explain please AngularJS $injector with a clear example

<p>Due to deficiency of official docs explanation on <code>$injector</code> (service) I have hard time understanding how it actually works. How many <code>$injector</code>s may be per application? When should I use it? How does <code>$injector</code> work? (and so on) Please provide me with a real world explanation and some JavaScript sandbox samples on it.</p>


If you prefer to see the question in working code, start here: http://jsbin.com/ayigub/2/edit

Consider this almost equivalent ways to write a simple direcive:
    
    app.directive(&quot;drinkShortcut&quot;, function() {
      return {
        scope: { flavor: &#39;@&#39;},
        template: &#39;&lt;div&gt;{{flavor}}&lt;/div&gt;&#39;
      };
    });

    app.directive(&quot;drinkLonghand&quot;, function() {
      return {
        scope: {},
        template: &#39;&lt;div&gt;{{flavor}}&lt;/div&gt;&#39;,
        link: function(scope, element, attrs) {
          scope.flavor = attrs.flavor;
        }
      };
    });

When used by themselves, the two directives work and behave identically:
      
      &lt;!-- This works --&gt;
      &lt;div drink-shortcut flavor=&quot;blueberry&quot;&gt;&lt;/div&gt;
      &lt;hr/&gt;

      &lt;!-- This works --&gt;
      &lt;div drink-longhand flavor=&quot;strawberry&quot;&gt;&lt;/div&gt;
      &lt;hr/&gt;

However, when used within an ng-repeat, only the shortcut version works:

      &lt;!-- Using the shortcut inside a repeat also works --&gt;
      &lt;div ng-repeat=&quot;flav in [&#39;cherry&#39;, &#39;grape&#39;]&quot;&gt;
        &lt;div drink-shortcut flavor=&quot;{{flav}}&quot;&gt;&lt;/div&gt;
      &lt;/div&gt;
      &lt;hr/&gt;
      
      &lt;!-- HOWEVER: using the longhand inside a repeat DOESN&#39;T WORK --&gt;      
      &lt;div ng-repeat=&quot;flav in [&#39;cherry&#39;, &#39;grape&#39;]&quot;&gt;
        &lt;div drink-longhand flavor=&quot;{{flav}}&quot;&gt;&lt;/div&gt;
      &lt;/div&gt;
      
My questions are:

1. Why does the longhand version not work inside an ng-repeat?
2. How could you make the longhand version work inside an ng-repeat?

Using a directive inside an ng-repeat, and a mysterious power of scope &#39;@&#39;

I have some text in a hidden textarea. When a button is clicked I would like to have the text offered for download as a `.txt` file. Is this possible using AngularJS or Javascript?

How do you serve a file for download with AngularJS or Javascript?

I have a template binding that displays a model attribute called &#39;date&#39; which is a date, using Angular&#39;s date filter.

    &lt;span class=&quot;gallery-date&quot;&gt;{{gallery.date | date:&#39;mediumDate&#39;}}&lt;/span&gt;

So far so good. However at the moment, if there is no value in the date field, the binding displays nothing. However, I would like it to display the string &#39;Various&#39; if there is no date.

I can get the basic logic using a binary operator:

    &lt;span class=&quot;gallery-date&quot;&gt;{{gallery.date || &#39;Various&#39;}}&lt;/span&gt;

However I can&#39;t get it to work with the date filter:

    &lt;span class=&quot;gallery-date&quot;&gt;{{gallery.date | date:&#39;mediumDate&#39; || &quot;Various&quot;}}&lt;/span&gt;

**How can I use the binary operator alongside the date filter?**


Angularjs Template Default Value if Binding Null / Undefined (With Filter)

Is there any way to make an expression for something like [`ng-class`][1] to be a conditional?

For example, I have tried the following:

    &lt;span ng-class=&quot;{test: &#39;obj.value1 == \&#39;someothervalue\&#39;&#39;}&quot;&gt;test&lt;/span&gt;

The issue with this code is that no matter what `obj.value1` is, the class test is always applied to the element. Doing this:

    &lt;span ng-class=&quot;{test: obj.value2}&quot;&gt;test&lt;/span&gt;

As long as `obj.value2` does not equal a truthy value, the class in not applied.  Now I can work around the issue in the first example by doing this:

    &lt;span ng-class=&quot;{test: checkValue1()}&quot;&gt;test&lt;/span&gt;

Where the `checkValue1` function looks like this:

    $scope.checkValue1 = function() {
      return $scope.obj.value === &#39;somevalue&#39;;
    }

I am just wondering if this is how `ng-class` is supposed to work.  I am also building a custom directive where I would like to do something similar to this. However, I can&#39;t find a way to watch an expression (and maybe that is impossible and the reason why it works like this).

Here is a [plnkr][2] to show what I mean.


  [1]: https://docs.angularjs.org/api/ng/directive/ngClass
  [2]: http://plnkr.co/edit/iSh0t8swDEyGbh7ylZg2?p=preview

AngularJS ngClass conditional

I have three controllers that are quite similar. I want to have a controller which these three extend and share its functions.

Content Type	Original Author	Original Content on Stackoverflow
Question	Mikalaj Murziankou	View Question on Stackoverflow
Solution 1 - Angularjs	Mark Rajcok	View Answer on Stackoverflow

Explain please AngularJS $injector with a clear example

Angularjs Problem Overview

Angularjs Solutions

Solution 1 - Angularjs

dynamic listview adding "Load more items" at the end of scroll

Using a proxy with .NET 4.5 HttpClient

Attributions