Come si crea un Pager di visualizzazione Android con un indicatore di punti?

Probabilmente molti di voi (come me), hanno problemi con la creazione ViewPagercon punti in basso, come questo:

Come si crea un ViewPager per Android?

Tutto ciò di cui abbiamo bisogno sono: ViewPager , TabLayout e 2 drawable per punti selezionati e predefiniti.

In primo luogo, dobbiamo aggiungere TabLayoutal nostro layout dello schermo e collegarlo con ViewPager. Possiamo farlo in due modi:

Nidificato TabLayoutinViewPager

<androidx.viewpager.widget.ViewPager
    android:id="@+id/photos_viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.tabs.TabLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</androidx.viewpager.widget.ViewPager>

In questo caso TabLayoutverrà automaticamente collegato ViewPager, ma TabLayoutsarà accanto ViewPager, non su di esso.

Separato TabLayout

<androidx.viewpager.widget.ViewPager
    android:id="@+id/photos_viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

<com.google.android.material.tabs.TabLayout
    android:id="@+id/tab_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"/>

In questo caso, possiamo metterlo TabLayoutovunque, ma dobbiamo collegarci TabLayouta livello di ViewPagercodice

ViewPager pager = (ViewPager) view.findViewById(R.id.photos_viewpager);
PagerAdapter adapter = new PhotosAdapter(getChildFragmentManager(), photosUrl);
pager.setAdapter(adapter);

TabLayout tabLayout = (TabLayout) view.findViewById(R.id.tab_layout);
tabLayout.setupWithViewPager(pager, true);

Una volta creato il nostro layout, dobbiamo preparare i nostri punti. Così creiamo tre file: selected_dot.xml, default_dot.xmle tab_selector.xml.

selected_dot.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape
            android:innerRadius="0dp"
            android:shape="ring"
            android:thickness="8dp"
            android:useLevel="false">
            <solid android:color="@color/colorAccent"/>
        </shape>    
    </item>
</layer-list>

default_dot.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape
            android:innerRadius="0dp"
            android:shape="ring"
            android:thickness="8dp"
            android:useLevel="false">
            <solid android:color="@android:color/darker_gray"/>
        </shape>    
    </item>
</layer-list>

tab_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/selected_dot"
          android:state_selected="true"/>

    <item android:drawable="@drawable/default_dot"/>
</selector>

Ora dobbiamo aggiungere solo 3 righe di codice TabLayoutnel nostro layout XML.

app:tabBackground="@drawable/tab_selector"
app:tabGravity="center"
app:tabIndicatorHeight="0dp"

Per ViewPager2leggere questo articolo:

ViewPager (2) con indicatore di punti su medium.com

I voti positivi sono i benvenuti ;-)

Per prima cosa, crea un layout, in modo da dare un LinerLayout per punti che viene visualizzato sul tuo View Pager

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>


    <LinearLayout
        android:id="@+id/pager_dots"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="10dp"
        android:background="@android:color/transparent"
        android:gravity="center_horizontal"
        android:orientation="horizontal">
    </LinearLayout>

</RelativeLayout>

Successivamente crea 2 drawable

1. Disegnabile non selezionato

<?xml version="1.0" encoding="utf-8"?>
<shape android:shape="oval" xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@android:color/transparent"/>
    <size android:width="12dp" android:height="12dp"/>

    <stroke android:width="1dp" android:color="#ffffff"/>
</shape>

2. Drawable selezionato

<?xml version="1.0" encoding="utf-8"?>
<shape android:shape="oval" xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@android:color/transparent"/>
    <size android:width="12dp" android:height="12dp"/>

    <stroke android:width="1dp" android:color="#000000"/>
</shape>

Dopo quell'adattatore impostato

private LinearLayout llPagerDots;
private ViewPager viewPager;
private ArrayList<String> eventImagesUrl;
private HomeViewPagerAdapter homeViewPagerAdapter;
private ImageView[] ivArrayDotsPager;

public void setUpViewPager() {
    viewPager = (ViewPager) findViewById(R.id.view_pager);
    llPagerDots = (LinearLayout) findViewById(R.id.pager_dots);

    homeViewPagerAdapter = new HomeViewPagerAdapter(mContext, eventImagesUrl);

    viewPager.setAdapter(homeViewPagerAdapter);

    setupPagerIndidcatorDots();

    ivArrayDotsPager[0].setImageResource(R.drawable.page_indicator_selected);

    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            for (int i = 0; i < ivArrayDotsPager.length; i++) {
                ivArrayDotsPager[i].setImageResource(R.drawable.page_indicator_unselected);
            }
            ivArrayDotsPager[position].setImageResource(R.drawable.page_indicator_selected);
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });
}

Crea un metodo setupPagerIndidcatorDots ():

private void setupPagerIndidcatorDots() {
    ivArrayDotsPager = new ImageView[eventImagesUrl.size()];
    for (int i = 0; i < ivArrayDotsPager.length; i++) {
        ivArrayDotsPager[i] = new ImageView(getActivity());
        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        params.setMargins(5, 0, 5, 0);
        ivArrayDotsPager[i].setLayoutParams(params);
        ivArrayDotsPager[i].setImageResource(R.drawable.page_indicator_unselected);
        //ivArrayDotsPager[i].setAlpha(0.4f);
        ivArrayDotsPager[i].setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                view.setAlpha(1);
            }
        });
        llPagerDots.addView(ivArrayDotsPager[i]);
        llPagerDots.bringToFront();
    }

Puoi controllare la mia biblioteca per gestire la tua richiesta: https://github.com/tommybuonomo/dotsindicator

Nel tuo layout XML

  <com.tbuonomo.viewpagerdotsindicator.DotsIndicator
      android:id="@+id/dots_indicator"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      app:dotsColor="@color/colorPrimary"
      app:dotsSize="16dp"
      app:dotsWidthFactor="3"
      />

Nel tuo codice Java

dotsIndicator = (DotsIndicator) findViewById(R.id.dots_indicator);
viewPager = (ViewPager) findViewById(R.id.view_pager);
adapter = new ViewPagerAdapter();
viewPager.setAdapter(adapter);
dotsIndicator.setViewPager(viewPager);

<android.support.v4.view.ViewPager
      android:id="@+id/vpImage"
      android:layout_width="match_parent"
      android:layout_height="@dimen/_120sdp" />


<android.support.design.widget.TabLayout
      android:id="@+id/tlImage"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:tabBackground="@drawable/selector_product_image"
      app:tabGravity="center"
      app:tabIndicatorHeight="0dp"
      app:tabMaxWidth="12dp"
      app:tabRippleColor="@null" />

ImageAdapter imageAdapter = new ImageAdapter(context, arrayList);
vpImage.setOffscreenPageLimit(1);
vpImage.setAdapter(imageAdapter);
tlImage.setupWithViewPager(vpImage);

selector_product_image.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/image_selected" android:state_selected="true" />
    <item android:drawable="@drawable/image_unselected" />

</selector>

image_selected.xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape
            android:innerRadius="0dp"
            android:shape="ring"
            android:thickness="4dp"
            android:useLevel="false">
            <solid android:color="@color/colorAccent" />
        </shape>
    </item>
</layer-list>

image_unselected.xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape
            android:innerRadius="0dp"
            android:shape="ring"
            android:thickness="4dp"
            android:useLevel="false">
            <solid android:color="@color/colorPrimary" />
        </shape>
    </item>
</layer-list>

ImageAdapter.java

class ImageAdapter extends PagerAdapter {

  private Context context;
  private ArrayList<ImageModel> arrayList;
  private LayoutInflater layoutInflater;

  public ImageAdapter(Context context, ArrayList<ImageModel> arrayList) {
      this.context = context;
      this.arrayList = arrayList;
      this.layoutInflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  }

  @Override
  public int getCount() {
      return arrayList.size();
  }

  @Override
  public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
      return view == ((View) o);
  }

  @Override
  public Object instantiateItem(ViewGroup container, int position) {
      View view = layoutInflater.inflate(R.layout.row_slider_image, container, false);

      AppCompatImageView ivProductImage = view.findViewById(R.id.ivProductImage);

      if (!TextUtils.isEmpty(arrayList.get(position).getImage())) {
          Glide.with(context)
                  .load(arrayList.get(position).getImage())
                  .apply(new RequestOptions().placeholder(R.drawable.no_image).error(R.drawable.no_image))
                  .into(ivProductImage);
      }

      container.addView(view);
      return view;
  }

  @Override
  public void destroyItem(ViewGroup container, int position, Object object) {
      container.removeView((View) object);
  }
}

row_slider_image.xml

<android.support.v7.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.AppCompatImageView
        android:id="@+id/ivProductImage"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/no_image" />

</android.support.v7.widget.LinearLayoutCompat>

Il tuo xml

  <RelativeLayout
                android:id="@+id/rl_speed"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_above="@+id/ll_dashboard_buttons"
                android:layout_below="@+id/ib_menu">

                <com.smart.gps.speedometer.app.utils.SmartViewPager
                    android:id="@+id/view_pager"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" 
                   app:layout_behavior="@string/appbar_scrolling_view_behavior">
                   </com.smart.gps.speedometer.app.utils.SmartViewPager>

                   <android.support.design.widget.TabLayout
                    android:id="@+id/sliding_tabs"
                    android:layout_alignParentBottom="true"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    app:tabBackground="@drawable/tab_selector"
                    app:tabIndicatorHeight="0dp"
                    app:tabGravity="center"
                    />

crea un disegno. fare clic con il tasto destro su drawable -> new -> Drawable file nome risorsa quel file

tab_selector.xml

<item android:drawable="@drawable/selected_tab"
    android:state_selected="true"/>

<item android:drawable="@drawable/unselected_tab"/>

Ora ci sono altri due file XML. creare altri due file xml con il nome rispettato. questi sono l'indicatore di selezione e l'indicatore non selezionato

selected_tab.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape
            android:innerRadius="0dp"
            android:shape="ring"
            android:thickness="4dp"
            android:useLevel="false">
            <solid android:color="@color/highspeed"/>
        </shape>
    </item>
</layer-list>

unselected_tab.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape
            android:innerRadius="0dp"
            android:shape="ring"
            android:thickness="2dp"
            android:useLevel="false">
            <solid android:color="@android:color/darker_gray"/>
        </shape>
    </item>
</layer-list>

Quando vuoi qualcosa di simile a questo con l'ultimo ViewPager2 e Kotlin

Tutto si spiega da sé, non c'è bisogno di spiegare!

1. La tua attività o frammento

val imageList = listOf(
        ImageModel(R.drawable.offer1),
        ImageModel(R.drawable.splash),
        ImageModel(R.drawable.offer1),
        ImageModel(R.drawable.splash2)
    )

    val adapter = HomeOffersAdapter()
    adapter.setItem(imageList)
    photos_viewpager.adapter = adapter

    TabLayoutMediator(tab_layout, photos_viewpager) { tab, position ->
    }.attach()
}

2. Layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="@dimen/dp_200">

<androidx.viewpager2.widget.ViewPager2
    android:id="@+id/photos_viewpager"
    android:layout_width="match_parent"
    android:layout_height="@dimen/dp_200" />

<com.google.android.material.tabs.TabLayout
    android:id="@+id/tab_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_gravity="bottom|center"
    app:tabBackground="@drawable/tab_selector"
    app:tabGravity="center"
    app:tabIndicatorHeight="0dp"
    app:tabSelectedTextColor="@android:color/transparent"
    app:tabTextColor="@android:color/transparent" />

3. Drawable: tab_selector.xml

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/dot_selected" android:state_selected="true" />
<item android:drawable="@drawable/dot_default" />

4. Disegnabile: dot_selected.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:innerRadius="0dp"
android:shape="ring"
android:thickness="@dimen/dp_8"
android:useLevel="false">

<solid android:color="@color/colorPrimary" />

<stroke
    android:width="@dimen/dp_1"
    android:color="@android:color/white" />

5. Drawable: dot_default.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:innerRadius="0dp"
android:shape="ring"
android:thickness="@dimen/dp_8"
android:useLevel="false">

<solid android:color="@android:color/transparent" />

<stroke
    android:width="@dimen/dp_1"
    android:color="@android:color/white" />

6. Adattatore

class HomeOffersAdapter : RecyclerView.Adapter<HomeOffersAdapter.HomeOffersViewHolder>() {

private var list: List<ImageModel> = listOf()


override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): HomeOffersViewHolder {
    return HomeOffersViewHolder(parent)
}


override fun onBindViewHolder(holder: HomeOffersViewHolder, position: Int) {
    holder.bind(list[position])
}

fun setItem(list: List<ImageModel>) {
    this.list = list
    notifyDataSetChanged()
}

override fun getItemCount(): Int = list.size

class HomeOffersViewHolder constructor(itemView: View) : RecyclerView.ViewHolder(itemView) {

    constructor(parent: ViewGroup) : this(
        LayoutInflater.from(parent.context).inflate(
            R.layout.pager_item,
            parent, false
        )
    )

    fun bind(imageModel: ImageModel) {
        itemView.offerImage.setImageResource(imageModel.image)
    }
}

}

7. Layout: pager_item.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:orientation="vertical">

<androidx.appcompat.widget.AppCompatImageView
    android:id="@+id/offerImage"
    android:layout_width="match_parent"
    android:layout_height="@dimen/dp_200"
    android:adjustViewBounds="true"
    android:scaleType="fitXY"
    tools:src="@drawable/offer1" />

Posiziona ViewFlipper e viewFlipper_linear_dot_lay (Linearlayout) sulla stessa linea di base e segui la seguente

viewFlipper_linear_dot_lay= (LinearLayout) findViewById(R.id.dots_lay);
setupDotsOnViewPager(images_viewFlipper);
    for (int i = 0; i < images_viewFlipper.size(); i++) {
    //Add Images to ViewFlipper 
    }



private void setupDotsOnViewPager(ArrayList images_viewFlipper) {
                    images_linear = new ImageView[images_viewFlipper.size()];
                    for (int i = 0; i < images_linear.length; i++) {
                        images_linear[i] = new ImageView(this);
                        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
                        params.setMargins(5, 0, 5, 0);
                        params.gravity = Gravity.BOTTOM | Gravity.CENTER;
                        images_linear[i].setLayoutParams(params);
                        images_linear[i].setImageResource(R.drawable.unselected);
                        viewFlipper_linear_dot_lay.addView(images_linear[i]);
                        viewFlipper_linear_dot_lay.bringToFront();
                    }
                }

E OnRight & OnLeft ottiene il seguente codice

for (int i = 0; i < images_linear.length; i++) {
 images_linear[i].setImageResource(R.drawable.unselected);
 }
images_linear[viewFlipper.getDisplayedChild()].setImageResource(R.drawable.selected);

Aggiungi dipendenze> Sincronizza il Gradle

implementation 'com.tbuonomo.andrui:viewpagerdotsindicator:4.1.2'

Nel tuo codice Java

 dotsIndicator = (DotsIndicator) findViewById(R.id.dots_indicator3);


myViewPagerAdapter = new MyViewPagerAdapter();
        viewPager.setAdapter(myViewPagerAdapter);
        viewPager.addOnPageChangeListener(viewPagerPageChangeListener);
        dotsIndicator.setViewPager(viewPager);

Nel tuo layout

<com.tbuonomo.viewpagerdotsindicator.SpringDotsIndicator
android:id="@+id/spring_dots_indicator"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:dampingRatio="0.5"
app:dotsColor="@color/material_white"
app:dotsStrokeColor="@color/material_yellow"
app:dotsCornerRadius="2dp"
app:dotsSize="16dp"
app:dotsSpacing="6dp"
app:dotsStrokeWidth="2dp"
app:stiffness="300"
/>