When we delete a item in our recyclerView, first step is in our adapter We must to add this:
void deleteItem(int index) {
mDataset.remove(index);
notifyItemRemoved(index);
}
And now our fragment or activity we call the method like this:
mAdapter.deleteItem(position);
The example is in GitHub
Hopefully this steps will help you removing items from a recycler view, please, drop us a comment if you have any problems with this code.
In this example you can learn how to test server call with Mockito and RxJava, We need this elements:
1. Service
2. RemoteDataSource
3. RemoteDataSourceTest
Simple Service:
public interface Service {
String URL_BASE = "https://guessthebeach.herokuapp.com/api/";
@GET("topics/")
Observable<List<Topics>> getTopicsRx();
}
For RemoteDataSource
public class RemoteDataSource implements Service {
private Service api;
public RemoteDataSource(Retrofit retrofit) {
this.api = retrofit.create(Service.class);
}
@Override
public Observable<List<Topics>> getTopicsRx() {
return api.getTopicsRx();
}
}
The key is MockWebServer from okhttp3.
This library makes it easy to test that your app Does The Right Thing when it makes HTTP and HTTPS calls. It lets you specify which responses to return and then verify that requests were made as expected.
Because it exercises your full HTTP stack, you can be confident that you’re testing everything. You can even copy & paste HTTP responses from your real web server to create representative test cases. Or test that your code survives in awkward-to-reproduce situations like 500 errors or slow-loading responses.
Use MockWebServer the same way that you use mocking frameworks like Mockito:
Here’s a complete example in RemoteDataSourceTest:
public class RemoteDataSourceTest {
List<Topics> mResultList;
MockWebServer mMockWebServer;
TestSubscriber<List<Topics>> mSubscriber;
@Before
public void setUp() {
Topics topics = new Topics(1, "Discern The Beach");
Topics topicsTwo = new Topics(2, "Discern The Football Player");
mResultList = new ArrayList();
mResultList.add(topics);
mResultList.add(topicsTwo);
mMockWebServer = new MockWebServer();
mSubscriber = new TestSubscriber<>();
}
@Test
public void serverCallWithError() {
//Given
String url = "dfdf/";
mMockWebServer.enqueue(new MockResponse().setBody(new Gson().toJson(mResultList)));
Retrofit retrofit = new Retrofit.Builder()
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create())
.baseUrl(mMockWebServer.url(url))
.build();
RemoteDataSource remoteDataSource = new RemoteDataSource(retrofit);
//When
remoteDataSource.getTopicsRx().subscribe(mSubscriber);
//Then
mSubscriber.assertNoErrors();
mSubscriber.assertCompleted();
}
@Test
public void severCallWithSuccessful() {
//Given
String url = "https://guessthebeach.herokuapp.com/api/";
mMockWebServer.enqueue(new MockResponse().setBody(new Gson().toJson(mResultList)));
Retrofit retrofit = new Retrofit.Builder()
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create())
.baseUrl(mMockWebServer.url(url))
.build();
RemoteDataSource remoteDataSource = new RemoteDataSource(retrofit);
//When
remoteDataSource.getTopicsRx().subscribe(mSubscriber);
//Then
mSubscriber.assertNoErrors();
mSubscriber.assertCompleted();
}
}
You can check my example in GitHub
When We add a item in our recyclerView, first step is in our adapter We must to add this:
void addItem(VerticalData dataObj, int index) {
mDataset.add(dataObj);
notifyItemInserted(index);
}
And now our fragment or activity we call the method like this:
mAdapter.addItem(object, mAdapter.getItemCount());
In this example you can understand different elements of RxJava with Strings.
Simple
This method creates an Observable such that when an Observer subscribes, the onNext() of the Observer is immediately called with the argument provided to Observable.just(). The onCompleted() will then be called since the Observable has no other values to emit.
Observable.create(subcriber ->{
subcriber.onNext("Hello");
subcriber.onNext("Javier Gonzalez");
subcriber.onCompleated();
});
Now with Exception:
Observable.create(subcriber ->{
subcriber.onNext("Hello");
subcriber.onNext("Javier Gonzalez");
subcriber.onError(new Exception("iOS user now allowed"));
});
And there are another different ways to do:
Observable.just("Hello again...");
Observable.from(Arrays.asList("Hello", "again..."));
Observable.from(new String[]{"Hello", "again..."});
Observable.concat(Observable.just("Hello"), Observable.just("again..."));
Observable.merge(Observable.just("Hello", "again..."), Observable.never());
If you want a good tutorial in your apps, you can make a carousel.
We can use my favorite library for tutorial
compile "com.romandanylyk:pageindicatorview:0.1.1"
In the layout We should add ViewPager and the Indicator.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:attrs="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.thedeveloperworldisyours.carouselviewpager.MainActivity">
<android.support.v4.view.ViewPager
android:id="@+id/activity_main_view_pager"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<com.rd.PageIndicatorView
android:id="@+id/tutorial_activity_page_indicator_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="10dp"
attrs:piv_animationType="drop"
attrs:piv_dynamicCount="true"
attrs:piv_interactiveAnimation="true"
attrs:piv_padding="16dp"
attrs:piv_radius="8dp"
attrs:piv_selectedColor="@color/colorAccent"
attrs:piv_unselectedColor="@color/colorPrimaryDark"
attrs:piv_viewPager="@id/activity_main_view_pager" />
</RelativeLayout>
We can custom the item
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical">
<com.thedeveloperworldisyours.carouselviewpager.CustomLinearLayout
android:id="@+id/item_root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/transparent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:id="@+id/item_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="@dimen/item_size_text" />
<Button
android:id="@+id/item_content"
android:layout_width="230dp"
android:layout_height="120dp"
android:background="@android:color/black"/>
</com.thedeveloperworldisyours.carouselviewpager.CustomLinearLayout>
</LinearLayout>
public class CustomFragment extends Fragment {
public static Fragment newInstance(Activity context, int position, float scale) {
Bundle bundle = new Bundle();
bundle.putInt("position", position);
bundle.putFloat("scale", scale);
return Fragment.instantiate(context, CustomFragment.class.getName(), bundle);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
LinearLayout linearLayout = (LinearLayout)
inflater.inflate(R.layout.item, container, false);
int position = this.getArguments().getInt("position");
TextView textView = (TextView) linearLayout.findViewById(R.id.item_text);
textView.setText(String.valueOf(position));
CustomLinearLayout root = (CustomLinearLayout) linearLayout.findViewById(R.id.item_root);
float scale = this.getArguments().getFloat("scale");
root.setScaleBoth(scale);
return linearLayout;
}
}
public class CustomLinearLayout extends LinearLayout {
private float mScale = BIG_SCALE;
public CustomLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomLinearLayout(Context context) {
super(context);
}
public void setScaleBoth(float scale) {
this.mScale = scale;
this.invalidate(); // If you want to see the mScale every time you set
// mScale you need to have this line here,
// invalidate() function will call onDraw(Canvas)
// to redraw the view for you
}
@Override
protected void onDraw(Canvas canvas) {
// The main mechanism to display mScale animation, you can customize it
// as your needs
int w = this.getWidth();
int h = this.getHeight();
canvas.scale(mScale, mScale, w / 2, h / 2);
super.onDraw(canvas);
}
}
public class CustomPagerAdapter extends FragmentPagerAdapter implements ViewPager.PageTransformer {
public final static float BIG_SCALE = 1.0f;
public final static float SMALL_SCALE = 0.7f;
public final static float DIFF_SCALE = BIG_SCALE - SMALL_SCALE;
private Activity mContext;
private FragmentManager mFragmentManager;
private float mScale;
public CustomPagerAdapter(Activity context, FragmentManager fragmentManager) {
super(fragmentManager);
this.mFragmentManager = fragmentManager;
this.mContext = context;
}
@Override
public Fragment getItem(int position) {
// make the first mViewPager bigger than others
if (position == FIRST_PAGE)
mScale = BIG_SCALE;
else
mScale = SMALL_SCALE;
return CustomFragment.newInstance(mContext, position, mScale);
}
@Override
public int getCount() {
return PAGES;
}
@Override
public void transformPage(View page, float position) {
CustomLinearLayout myLinearLayout = (CustomLinearLayout) page.findViewById(R.id.item_root);
float scale = BIG_SCALE;
if (position > 0) {
scale = scale - position * DIFF_SCALE;
} else {
scale = scale + position * DIFF_SCALE;
}
if (scale < 0) scale = 0;
myLinearLayout.setScaleBoth(scale);
}
}
public class MainActivity extends AppCompatActivity {
public final static int PAGES = 5;
public final static int FIRST_PAGE = 0 ;
public CustomPagerAdapter mAdapter;
public ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mViewPager = (ViewPager) findViewById(R.id.activity_main_view_pager);
mAdapter = new CustomPagerAdapter(this, this.getSupportFragmentManager());
mViewPager.setAdapter(mAdapter);
mViewPager.setPageTransformer(false, mAdapter);
// Set current item to the middle page so we can fling to both
// directions left and right
mViewPager.setCurrentItem(FIRST_PAGE);
// Necessary or the mViewPager will only have one extra page to show
// make this at least however many pages you can see
mViewPager.setOffscreenPageLimit(3);
// Set margin for pages as a negative number, so a part of next and
// previous pages will be showed
mViewPager.setPageMargin(-400);
}
}