Ah, I figure it out.

    RelativeLayout.LayoutParams layout = (LayoutParams) myChild.getLayoutParams();
    layout.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, 0);

So there is really no removeRule until API 17.

Depending on the situation, in my case I created new `LayoutParams` and then added rules which were needed

can anyone please explain what is wrong with this code?

    str1=&#39;&quot;xxx&quot;&#39;
    print str1
    if str1[:1].startswith(&#39;&quot;&#39;):
        if str1[:-1].endswith(&#39;&quot;&#39;):
            print &quot;hi&quot;
        else:
            print &quot;condition fails&quot;
    else:
        print &quot;bye&quot;   

The output I got is:

&lt;!-- language: lang-none --&gt;

    Condition fails

but I expected it to print `hi` instead.

Python Checking a string&#39;s first and last character

I have an AngularJS service defined in the following way

    angular.module(&#39;myService&#39;).service(&#39;myService&#39;, function() {
      this.publicFunction(param) {
        ...
      };

      this.anotherPublicFunction(param) {
        // how to call publicFunction(param)?
        ...
      };
    });    

and I would like to call the first function both from outside the service (which works fine by `myService.publicFunction(xxx)`) and from another function in the same service, i.e. `anotherPublicFunction`. &lt;del&gt;Neither one of `this.publicFunction(param)` or `myService.publicFunction(param)` won&#39;t work from within the second function, and I can understand that.&lt;/del&gt;

---
**EDIT:**&lt;br /&gt;
*Actually the whole problem was caused by something you can&#39;t reproduce with my example alone. I passed the second function as a callback parameter to another function in a separate controller, and when it is called, the reference to `this` doesn&#39;t work.*

*E.g.*

    anotherService.someCall(&#39;a&#39;, 123, myService.anotherPublicFunction);

*fails inside `anotherPublicFunction` because `this` can&#39;t be resolved.*

*I&#39;ve written a Plunker to show the problem:*
http://plnkr.co/edit/rrRs9xnZTNInDVdapiqF?p=info

*(I&#39;ll still leave the question here in case it will help someone else.)*

---


I know I could get around the problem by using a reference to the service or the first function like this

    var ms = this;
    this.anotherPublicFunction(param) {
      ms.publicFunction(param);
      ...
    };

or this

    var pf = this.publicFunction;
    this.anotherPublicFunction(param) {
      pf(param);
      ...
    };

but both seem like dirty hacks.

**Is there a good way to call the first function from the second one in this case? Or am I doing something totally wrong in the first place to have a service like this?**

I found these questions with good answers:

- https://stackoverflow.com/questions/16753825/angularjs-share-functions-inside-service
- https://stackoverflow.com/questions/18853797/angularjs-call-an-internal-service-function-from-self

but they differ from my problem since one of them has a separate, internal function that was to be called, and the other one was using a factory instead of a service.

**EDIT:**

After posting this I immediately realized I could also do this:

    var actualWork = function(param) {
      ...
    }

    this.publicFunction(param) {
      actualWork(param);
    };

    this.anotherPublicFunction(param) {
      actualWork(param);
      ...
    };

which doesn&#39;t seem quite as bad as the other options so far... Are there better approaches?

Calling a function in AngularJS service from the same service?

Prior to API 17, how do I remove a rule from a layout? I have a RelativeLayout with a number of children. The RelativeLayout is the main layout of my activity. After adding the rule programmatically using 

    RelativeLayout.LayoutParams layout = (LayoutParams) theChild.getLayoutParams();
    layout.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);

I need to remove the rule programmatically at some later time. How would I do this assuming earlier API than 17?

remove rule from RelativeLayout before api 17

Prior to API 17, how do I remove a rule from a layout? I have a RelativeLayout with a number of children. The RelativeLayout is the main layout of my activity. After adding the rule programmatically using
<pre><code class="hljs language-ini">RelativeLayout.LayoutParams layout = (LayoutParams) theChild.getLayoutParams();
layout.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
</code></pre>
I need to remove the rule programmatically at some later time. How would I do this assuming earlier API than 17?

When I run Genymotion, I get the following error:

&gt; Unable to start the Genymotion virtual device.
&gt;
&gt; Unable to configure the network adapter for the virtual device.
&gt;
&gt; Please, check the following points:  
From VirtualBox, in the main parameters of software, check a network adapter &quot;Host-only&quot; is present.
From VirtualBox, in the Genymotion virtual device parameters, check the first network interface has the type &quot;Host-only&quot;. If no, then set this parameter manually.

How can I fix that?


GenyMotion Unable to start the Genymotion virtual device

There are a lot of discussions about whether you should use `Activities` or `Fragments`.
For example:

 - [To-Fragment-or-not-to-Fragment][1]
 - [One Activity and all other Fragments][2]
 - [How many Activities vs. Fragments][3]
 - [Use Activity or Fragment in Android Application][4]

Most of the discussions I found were released before Android 4.2.   
With Android 4.2 Google invented [nested Fragments][5].

Therefore I actually don&#39;t see any reason anymore to use more than one `Activity`.

In the early stage of `Fragments` they were supposed to be used within Apps for supporting **Tablets** and **Smartphones** in a comfortable way at the same time. 

Thus for example you have a `ListView` which can open a detail `View` on click on an item. On a Smartphone we would replace the `ListView` and show the detailed `View` instead. Whereas a **Tablet** instead of replacing the List with the detail View can show both `Views` at the same time.

----------------------

Now with nested `Fragments` there are a lot of other possibilities. In case you want to use a single `Activity`, you could store general information in the `Activity` and every `Fragment` would have access to it. 

Besides this, `Fragments` who have nested `Fragments`, could also store information for their children `Fragments`. 

With `Fragments` I can easily reuse the `Views`, I can show more than one `Fragment` at the same time and I can easly form a dialog out of a `Fragment`. This all would take me probably not more than just some copy &amp; paste actions.

If I use `Activities` instead I seriously have to change a lot to get this done. 

------
I recently implemented an **Application** where I easily could use two `Fragment-ViewPager` to get things really beautiful and dynamic (Some kind of: Today&#39;s Information - Yesterday&#39;s Information). 
In my opinion `Fragments` make our life a way easier :) 

------

**Questions:**

 - **Why should I use more than one `Activity`?**

Could you provide any good example in which the usage of multiple `Activities` makes more sense instead of using `Fragments`?

 - **Are there any good examples where you don&#39;t have any choice but to use `Activities`?**

I think most of the bigger frameworks like **Maps**, **YouTube** and co already support `Fragments`. So we don&#39;t have to rely on `Activities`. 
Also is it quite easy to deal with `NavigationBar`, `TabHosts`, `ViewPager`, `ActionBar` in case you use `Fragments`. 


----------


**From Udacity:** 

Why not always create one Activity with lots of Fragments?

 1. Increased Complexity
 2. Harder Intent handling
 3. Difficult to read, maintain and test
 4. Risk of tight coupling
 5. Security concerns

 


  [1]: http://andytsui.wordpress.com/2011/10/23/to-fragment-or-not-to-fragment/
  [2]: https://stackoverflow.com/questions/12154505/one-activity-and-all-other-fragments
  [3]: https://stackoverflow.com/questions/12363790/how-many-activities-vs-fragments
  [4]: https://stackoverflow.com/questions/18885311/use-activity-or-fragment-in-android-application?rq=1
  [5]: http://developer.android.com/about/versions/android-4.2.html#NestedFragments

To Fragment or not to Fragment - Nested Fragments against Activities. Why should I use more than one Activity?

I was working on a project, and then I got a prompt to update Android Studio. After I did that, I started getting this error when trying to run my app
![Error][1]


  [1]: http://i.stack.imgur.com/czr5p.png

It says  

&gt; The project may need to be synced with Gradle files


How do I solve this?

Syncing Android Studio project with Gradle files

I&#39;m currently developing a physics app that is supposed to show a list of formulas and even solve some of them (the only problem is the `ListView`)

**This is my main layout**

        &lt;LinearLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:tools=&quot;http://schemas.android.com/tools&quot;
        android:layout_width=&quot;fill_parent&quot;
        android:layout_height=&quot;wrap_content&quot;
        android:measureWithLargestChild=&quot;false&quot;
        android:orientation=&quot;vertical&quot;
        tools:context=&quot;.CatList&quot; &gt;
        
    
        &lt;RelativeLayout
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;wrap_content&quot;
            android:background=&quot;@drawable/titlebar&quot; &gt;
    
            &lt;TextView
                android:id=&quot;@+id/Title1&quot;
                android:layout_width=&quot;wrap_content&quot;
                android:layout_height=&quot;wrap_content&quot;
                android:layout_centerHorizontal=&quot;true&quot;
                android:layout_centerVertical=&quot;true&quot;
                android:text=&quot;@string/app_name&quot;
                android:textAppearance=&quot;?android:attr/textAppearanceLarge&quot;
                android:textColor=&quot;#ff1c00&quot;
                android:textIsSelectable=&quot;false&quot; /&gt;
    
        &lt;/RelativeLayout&gt;
    
        &lt;ListView
            android:id=&quot;@+id/listFormulas&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;wrap_content&quot; &gt;
    
        &lt;/ListView&gt;
    
    &lt;/LinearLayout&gt;

**And this is my main activity**

    package com.wildsushii.quickphysics;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.ArrayList;
    import java.util.HashMap;
    
    import org.json.JSONException;
    import org.json.JSONObject;
    
    import android.os.Bundle;
    import android.app.Activity;
    import android.content.Context;
    import android.content.res.AssetManager;
    import android.view.Menu;
    import android.widget.ListView;
    
    public class CatList extends Activity {
    	
    	
    	
    	public static String AssetJSONFile (String filename, Context context) throws IOException {
            AssetManager manager = context.getAssets();
            InputStream file = manager.open(filename);
            byte[] formArray = new byte[file.available()];
            file.read(formArray);
            file.close();
            
            return new String(formArray);
        }
    
    	
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_cat_list);
    		ListView categoriesL = (ListView)findViewById(R.id.listFormulas);
    		
    		ArrayList&lt;HashMap&lt;String, String&gt;&gt; formList = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;();
    		Context context = null;
    		try {
    			String jsonLocation = AssetJSONFile(&quot;formules.json&quot;, context);
    			JSONObject formArray = (new JSONObject()).getJSONObject(&quot;formules&quot;);
    			String formule = formArray.getString(&quot;formule&quot;);
    			String url = formArray.getString(&quot;url&quot;);
    		} catch (IOException e) {
    			e.printStackTrace();
    		} catch (JSONException e) {
    			e.printStackTrace();
    		}
    		
    		//My problem is here!!
    	}
    
    	
    	@Override
    	public boolean onCreateOptionsMenu(Menu menu) {
    		// Inflate the menu; this adds items to the action bar if it is present.
    		getMenuInflater().inflate(R.menu.cat_list, menu);
    		return true;
    	}
    }

I actually know I can make this without using JSON but I need more practice parsing JSON. By the way, this is the JSON

        {
    	&quot;formules&quot;: [
        {
          &quot;formule&quot;: &quot;Linear Motion&quot;,
          &quot;url&quot;: &quot;qp1&quot;
        },
        {
          &quot;formule&quot;: &quot;Constant Acceleration Motion&quot;,
          &quot;url&quot;: &quot;qp2&quot;
        },
        {
          &quot;formule&quot;: &quot;Projectile Motion&quot;,
          &quot;url&quot;: &quot;qp3&quot;
        },
        {
          &quot;formule&quot;: &quot;Force&quot;,
          &quot;url&quot;: &quot;qp4&quot;
        },
        {
          &quot;formule&quot;: &quot;Work, Power, Energy&quot;,
          &quot;url&quot;: &quot;qp5&quot;
        },
        {
          &quot;formule&quot;: &quot;Rotary Motion&quot;,
          &quot;url&quot;: &quot;qp6&quot;
        },
        {
          &quot;formule&quot;: &quot;Harmonic Motion&quot;,
          &quot;url&quot;: &quot;qp7&quot;
        },
        {
          &quot;formule&quot;: &quot;Gravity&quot;,
          &quot;url&quot;: &quot;qp8&quot;
        },
        {
          &quot;formule&quot;: &quot;Lateral and Longitudinal Waves&quot;,
          &quot;url&quot;: &quot;qp9&quot;
        },
        {
          &quot;formule&quot;: &quot;Sound Waves&quot;,
          &quot;url&quot;: &quot;qp10&quot;
        },
        {
          &quot;formule&quot;: &quot;Electrostatics&quot;,
          &quot;url&quot;: &quot;qp11&quot;
        },
        {
          &quot;formule&quot;: &quot;Direct Current&quot;,
          &quot;url&quot;: &quot;qp12&quot;
        },
        {
          &quot;formule&quot;: &quot;Magnetic Field&quot;,
          &quot;url&quot;: &quot;qp13&quot;
        },
        {
          &quot;formule&quot;: &quot;Alternating Current&quot;,
          &quot;url&quot;: &quot;qp14&quot;
        },
        {
          &quot;formule&quot;: &quot;Thermodynamics&quot;,
          &quot;url&quot;: &quot;qp15&quot;
        },
        {
          &quot;formule&quot;: &quot;Hydrogen Atom&quot;,
          &quot;url&quot;: &quot;qp16&quot;
        },
        {
          &quot;formule&quot;: &quot;Optics&quot;,
          &quot;url&quot;: &quot;qp17&quot;
        },
        {
          &quot;formule&quot;: &quot;Modern Physics&quot;,
          &quot;url&quot;: &quot;qp18&quot;
        },
        {
          &quot;formule&quot;: &quot;Hydrostatics&quot;,
          &quot;url&quot;: &quot;qp19&quot;
        },
        {
          &quot;formule&quot;: &quot;Astronomy&quot;,
          &quot;url&quot;: &quot;qp20&quot;
        }
      ]
    }

I have tried a lot of things and even delete the entire project to make a new one :(

How can I parse a local JSON file from assets folder into a ListView?

I am creating a pixel-hunting game. So my activity shows an ImageView. And I want to create a hint &quot;show me where is the object&quot;. For this I need to blur whole image except a circle around a point where the object is located. Instead of blur I can show a just semitransparent black background.
There is there is no problem to draw a semitransparent rectangle on the Canvas.
But I don&#39;t know how to crop a transparent circle from it. 
The result should look like like this:
![enter image description here][1]


  [1]: http://i.stack.imgur.com/tcpdJ.jpg

Please help me to achieve same result on Android SDK.

Android canvas: draw transparent circle on image

Is it possible to create placeholder text that is only visible during the layout design process in Android Studio?

For example, say I have 2 TextViews in a linear layout that are going to be dynamically populated. During the design phase, I use placeholder text to ensure I get padding and such correct. I often forget to remove placeholder text, so during loading of the new data, the old data will appear for a split second... looks tacky.

It would be cool if there was a field similar to `android:placeholderText=&quot;This is placeholder text&quot;` that would only display in the preview. There isn&#39;t such a thing that I&#39;ve happened to have missed is there?

Placeholder text (design process only) in Android layout?

I have a nested layout like the following:

     &lt;LinearLayout&gt;     &lt;!----Parent layout---&gt;
        &lt;LinearLayout&gt;    &lt;!-----child 1---&gt;
           ...
        &lt;/LinearLayout&gt;   &lt;!----child 1 ended---&gt;
        &lt;LinearLayout&gt;    &lt;!-----child 2---&gt;
           ...
        &lt;/LinearLayout&gt;   &lt;!----child 2 ended---&gt;
     &lt;/LinearLayout&gt;    &lt;!----Parent endded---&gt;

The problem I am having now is that since all my data items are within child 1 or child 2 `Linearlayout`, if I add or delete a item the child linearlayout will animated with the effect of animateLayoutChanges but the parent layout will not do any animation. (I have `android:animateLayoutChanges` set to `true` for all linear layouts). Especially when I delete an item within child 1 the animation effect becomes weird (basically child 2 will jump up while child 1 is still doing its animation). 

Does anybody have any idea how to solve this?

Thanks  


**UPDATE**
 
Shortly after I posted this question, I found this on android developer&#39;s site in the LayoutTransition API. 

&gt; Using LayoutTransition at multiple levels of a nested view hierarchy may not work due to the interrelationship of the various levels of layout.

So does anyone have any work around suggestions for this issue?

animateLayoutChanges does not work well with nested layout?

 I&#39;m trying to align LinearLayout&#39;s vertical center which shows following pic (skycolor border) to delete button&#39;s vertical center.

so I set the gravity of id:groupNumbers to center_vertical.

but no changed. 

How to align id:groupNumbers to button&#39;s center?

![enter image description here][1]



    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    
    &lt;LinearLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
                  android:orientation=&quot;horizontal&quot;
                  android:layout_width=&quot;match_parent&quot;
                  android:layout_height=&quot;match_parent&quot;&gt;
    
        &lt;LinearLayout
                android:id=&quot;@+id/groupNumbers&quot;
                android:orientation=&quot;horizontal&quot;
                android:gravity=&quot;center_vertical&quot;
                android:layout_weight=&quot;0.7&quot;
                android:layout_width=&quot;wrap_content&quot;
                android:layout_height=&quot;wrap_content&quot;&gt;
    
            &lt;LinearLayout
                    android:orientation=&quot;horizontal&quot;
                    android:layout_weight=&quot;1&quot;
                    android:layout_width=&quot;wrap_content&quot;
                    android:layout_height=&quot;wrap_content&quot;&gt;
    
                &lt;TextView
                        android:id=&quot;@+id/txtSelected01&quot;
                        android:text=&quot;00&quot;
                        android:textSize=&quot;30dp&quot;
                        android:gravity=&quot;center_horizontal&quot;
                        android:layout_weight=&quot;1&quot;
                        android:layout_width=&quot;wrap_content&quot;
                        android:layout_height=&quot;wrap_content&quot;/&gt;
            &lt;/LinearLayout&gt;
    
            &lt;LinearLayout
                    android:orientation=&quot;horizontal&quot;
                    android:layout_weight=&quot;1&quot;
                    android:layout_width=&quot;wrap_content&quot;
                    android:layout_height=&quot;wrap_content&quot;&gt;
    
                &lt;TextView
                        android:id=&quot;@+id/txtSelected02&quot;
                        android:text=&quot;00&quot;
                        android:textSize=&quot;30dp&quot;
                        android:gravity=&quot;center_horizontal&quot;
                        android:layout_weight=&quot;1&quot;
                        android:layout_width=&quot;0dp&quot;
                        android:layout_height=&quot;wrap_content&quot;/&gt;
            &lt;/LinearLayout&gt;
        &lt;/LinearLayout&gt;
    
    
        &lt;Button
                android:id=&quot;@+id/btn_deleteNum&quot;
                android:text=&quot;Delete&quot;
                android:textSize=&quot;20dp&quot;
                android:layout_weight=&quot;0.2&quot;
                android:layout_width=&quot;wrap_content&quot;
                android:layout_height=&quot;wrap_content&quot;/&gt;
    &lt;/LinearLayout&gt;


  [1]: http://i.stack.imgur.com/Xo100.png

How to align linearlayout to vertical center?

I would like to know The difference between `MotionEvent.getRawX` and `MotionEvent.getX` in android as one is numeric and the other is float?Whats the need to have both of these types?

Difference between MotionEvent.getRawX and MotionEvent.getX

I&#39;m wondering if it&#39;s possible to change the color of the ScrollView. 

I&#39;m not referring to the background color or the edges.&lt;br&gt;
I attached a print screen of the bar I&#39;m referring. For me, it&#39;s kind of transparnt. 

Here&#39;s how I defined it in the xml: 

    &lt;ScrollView  
        android:layout_width=&quot;wrap_content&quot; 
        android:layout_height=&quot;wrap_content&quot; 
        android:fadeScrollbars=&quot;false&quot;
        android:layout_toLeftOf=&quot;@+id/personalscores_BackButton&quot; 
        android:layout_marginRight=&quot;0dp&quot; &gt; 

![scroll bar][1]

  [1]: http://i.stack.imgur.com/okk1m.png

how to change color of the actual scroll in ScrollView android?

I need to implement an overlay (translucent) screen for my app, something similar to [Showcase View][1]

My guess was to use `FrameLayout` for this usecase, because it is used to stack items on top of each other. But I was surprised to see that the above library uses `RelativeLayout`.

My question is when to use `FrameLayout` then, if not in cases like this? What are the disadvantages if I go the `FrameLayout` way?

  [1]: https://github.com/Espiandev/ShowcaseView

FrameLayout vs RelativeLayout for overlays

I am confused about the difference between `ConstraintLayout` and `RelativeLayout`. Could someone please tell me the exact differences between them? 

Differences between ConstraintLayout and RelativeLayout

Is there a way to implement something similar to what `RelativeLayout` does on Android?

In particular I&#39;m looking for something similar to `centerInParent`, `layout_below:&lt;layout_id&gt;`, `layout_above:&lt;layout_id&gt;`, and `alignParentLeft`

For more reference on RelativeLayout: https://developer.android.com/reference/android/widget/RelativeLayout.LayoutParams.html

EDIT: here is an example of a layout relying on `RelativeLayout`

[![Screenshot][1]][1]


  [1]: https://i.stack.imgur.com/bgx6h.png

So in the image above, on top, the &quot;tofu&#39;s Songs&quot; text is aligned as `centerInParent` inside a `RelativeLayout`. Whereas the other 2 are `alignParentLeft` and `alignParentRight`

On each cell, where the fire icon is at, the number of likes on the bottom of it is aligned around the center of the flame icon. Also, the top and bottom title on each cell are aligned to the right and to the top and bottom of the image avatar, respectively. 

Content Type	Original Author	Original Content on Stackoverflow
Question	Cote Mounyo	View Question on Stackoverflow
Solution 1 - Android	Cote Mounyo	View Answer on Stackoverflow
Solution 2 - Android	TheSecond	View Answer on Stackoverflow

remove rule from RelativeLayout before api 17

Android Problem Overview

Android Solutions

Solution 1 - Android

Solution 2 - Android

Calling a function in AngularJS service from the same service?

Python Checking a string's first and last character

Attributions