Month: May 2017

I am a complete beginner in Spring.

I am right now trying to see if I can test RequestMapping, RequestBody, RequestResponse and RestTemplate.

I wanted to receive this object as response:

public interface TestObject {
    public int getId();
    public String getValue();
}

@Component
public class TestObjectImpl {

    private int id;
    private String value;

    public TestObjectImpl(int id, String value){
        this.id = id;
        this.value = value;
    }

    public int getId(){
        return id;
    }

    public String getValue(){
        return value;
    }
}

However, I get:

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'int' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1486) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:189) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1193) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1095) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at io.yclub.castr.ads_java.ApplicationServer.main(ApplicationServer.java:12) [main/:na]

So, it says,

Description:
Parameter 0 of constructor in io.yclub.castr.ads_java.google.adwords.model.TestObjectImpl required a bean of type 'int' that could not be found.

Action:
Consider defining a bean of type 'int' in your configuration.

But how do I really create a bean definition for ‘int’?

What have I done?

// EDIT

Thanks to KrishnaKuntala, it was just because i did not have a default constructor.

Putting one immediately resolved the issue.

Answer

You can Injecting simple properties and can easily access the properties with @Value annotation and placeholders:

@Component
public class TestObjectImpl {
    private int id;
    private String value;

    @Autowired
    public TestObjectImpl(@Value("${prop1}")int id, @Value("${prop2}")String value){
        this.id = id;
        this.value = value;
    }

    public int getId(){
        return id;
    }

    public String getValue(){
        return value;
    }
}

Then you need to add them to the applicationContext:

<context:property-placeholder .../>

Note

If you fix it with the default constructor, you will need another mechanism to initialize your bean, so, you have to know what you are doing if you want to add the non arg constructor instead of doing the previous.

I have an Angular app that I want to use particles.js in however I have no clue how to add it and get it working.

I’ve added it to the .angular-cli.json

  "scripts": [
    "../node_modules/particles.js/particles.js"
  ],

And I’ve imported it into my component

import * as  particlesJS from 'particles.js';

And attempted to initialize it using

  particlesJS.load('particles-js', 'assets/particles.json', function() {
    console.log('callback - particles.js config loaded');
  });

Has anyone got this working?

Answer

Here is how to do that:

1. Just import the particles.js in your index.html (cdn or local)

   <script src="https://cdn.jsdelivr.net/particles.js/2.0.0/particles.min.js"></script>
   

2. Put in the div anchor into your component template (you could also put it to index.html or somewhere else)

   <div id="particles-js"></div>
   

3. Make the package visible by adding a simple type definition (in your component or in the typings.d.ts)

   declare var particlesJS: any;
   

4. Initialize it in ngOnInit (or somewhere else)

   particlesJS.load('particles-js', 'particles.json', null);
   

I have made a little plunker example: http://plnkr.co/edit/GLRvYgNPJue4KqdMuAJB?p=preview

From the docs:

To run the AVD Manager, do one of the following:

• In Android Studio, select Tools > Android > AVD Manager.
• Click AVD Manager in the toolbar.

Neither of these things exist.

I went into the settings and found the AVD Manager menu item that isn’t displayed, and assigned it a keyboard shortcut, but it didn’t do anything.

Other sources on the web mention running android avd to start the AVD Manager, but this was deprecated and removed.

**************************************************************************
The "android" command is deprecated.
For manual SDK, AVD, and project management, please use Android Studio.
For command-line tools, use toolsbinsdkmanager.bat
and toolsbinavdmanager.bat
**************************************************************************

Invalid or unsupported command "avd"

How do I open the AVD Manager?

Answer

The React Native CLI creates an Android project in the android directory.

In Android Studio, you can import (or open) this folder as a project, rather than the outer directory, and the Tools > Android option should appear. (It might take a few seconds for some reason.)

I have a Snackbar which is as follows:

However, if the drop down of the AutoCompleteTextView is too long, the drop down will block the Snackbar.

As you can see in the above image, the Snackbar is actually showing. However, its visibility is blocked by the long drop down. You can see from the above image

I try to use the following Snackbar code. Adding bringToFront() doesn’t help much.

private void showSnackbar(String message) {
    Snackbar snackbar
            = Snackbar.make(getActivity().findViewById(R.id.content), message, Snackbar.LENGTH_LONG);
    snackbar.getView().bringToFront();
    snackbar.show();
}

R.id.content is a CoordinatorLayout:

    <android.support.design.widget.CoordinatorLayout
        android:id="@+id/content"
        android:background="?attr/MyActivityBackground"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:foreground="?attr/headerShadow" />

Is there any good way, to avoid Snackbar from being covered by AutoCompleteTextView‘s drop down?

Answer

I might have a solution for that case. Of course, there are some assumptions but maybe the solution would suit you.

The key here is putting AutoCompleteTextView inside CoordinatorLayout and add custom CoordinatorLayout.Behavior to it.

1. Create appropriate Behavior for your class:

   public class AutoCompleteTextViewBehaviour extends CoordinatorLayout.Behavior<AutoCompleteTextView> {
   
       public AutoCompleteTextViewBehaviour(Context context, AttributeSet attrs) {
           super(context, attrs);
       }
   
       @Override
       public boolean layoutDependsOn(CoordinatorLayout parent, AutoCompleteTextView child, View dependency) {
           return dependency instanceof Snackbar.SnackbarLayout;
       }
   }
   

2. Override a method layoutDependsOn:

   @Override
   public boolean layoutDependsOn(CoordinatorLayout parent, AutoCompleteTextView child, View dependency) {
       return dependency instanceof Snackbar.SnackbarLayout;
   }
   

3. Get reference to AutoCompleteTextView popup view:

   Unfortunately I haven’t found a simple solution for that. However can be done via reflection.

   @Nullable
   private View getPopupList(AutoCompleteTextView child) {
       try {
           Field popupField;
           Class clazz;
           if (child instanceof AppCompatAutoCompleteTextView) {
               clazz = child.getClass().getSuperclass();
           } else {
               clazz = child.getClass();
           }
           popupField = clazz.getDeclaredField("mPopup");
           popupField.setAccessible(true);
           ListPopupWindow popup = (ListPopupWindow) popupField.get(child);
           Field popupListViewField = popup.getClass().getDeclaredField("mDropDownList");
           popupListViewField.setAccessible(true);
           return (View) popupListViewField.get(popup);
       } catch (NoSuchFieldException e) {
           e.printStackTrace();
       } catch (IllegalAccessException e) {
           e.printStackTrace();
       }
       return null;
   }
   

4. Override onDependentViewChanged method:

   @Override
   public boolean onDependentViewChanged(CoordinatorLayout parent, final AutoCompleteTextView child, View dependency) {
       if (popupList == null) {
           popupList = getPopupList(child);
           if (popupList == null) {
               return super.onDependentViewChanged(parent, child, dependency);
           }
       }
       int dropdownBottom = child.getBottom() + child.getDropDownVerticalOffset() + popupList.getHeight();
       int snackBarTop = dependency.getTop();
       int difference = dropdownBottom - snackBarTop;
       if (difference > 0) {
           child.setDropDownHeight(popupList.getHeight() - difference);
           return true;
       } else {
           child.setDropDownHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
       }
       return super.onDependentViewChanged(parent, child, dependency);
   }
   

5. Apply the behavior to AutocompleteTextView in .xml:

   app:layout_behavior="com.example.package.AutoCompleteTextViewBehaviour"/>
   

Of course this is a very basic solution, that for example does not animate list height, but I think this is a good start. Here is the full gist.

From what i have read Room doesn’t allow you to issue database queries on the main thread (as can cause delays on the main thread)). so imagine i am trying to update a textview on the UI main thread which some data how would i get a call back. Let me show you an example. Imagine i want to store my business model data into a object called Events. We would therefore have a EventDao object:

imagine we have this DAO object below:

@Dao
public interface EventDao {

   @Query("SELECT * FROM " + Event.TABLE_NAME + " WHERE " + Event.DATE_FIELD + " > :minDate" limit 1)
   LiveData<List<Event>> getEvent(LocalDateTime minDate);

   @Insert(onConflict = REPLACE)
   void addEvent(Event event);

   @Delete
   void deleteEvent(Event event);

   @Update(onConflict = REPLACE)
   void updateEvent(Event event);

}

and now in some activity i have a textview and i’d like to update its value so i do this:

 myTextView.setText(EventDao.getEvent(someDate));/*i think this is illegal as im trying to call room dao on mainthread, therefore how is this done correctly ? would i need to show a spinner while it updates ?*/

since the fetching is occuring off of the main thread i dont think i can call it like this and expect a smooth update. Whats the best approach here ?

Some more information: i wanted to use the room database as mechanism for retrieving model information instead of keeping it statically in memory. so the model would be available to me locally through the db after i download it through a rest service.

UPDATE: so since i am returning a livedata then i can do this:

eventDao = eventDatabase.eventDao();
eventDao.getEvent().observe(this, event -> {
     myTextView.setText(event.get(0));
});

and that works for something very small. but imagine my database has a million items. then when i do this call, there will be a delay retrieving the data. The very first time this gets called it will be visible to the user that there is a delay. How to avoid this ? So to be clear , there are times i do not want live data, i just need to update once the view. I need to know how to do this ? even if its not with liveData.

Answer

If you want to do your query synchronously and not receive notifications of updates on the dataset, just don’t wrap you return value in a LiveData object. Check out the sample code from Google.

Take a look at loadProductSync() here