Android uses Viewpager loop ad bit to achieve _android

How to implement loop playback

Now online loop playback is done in the adapter GetCount () method returns a larger value and Instantiateitem (ViewGroup container, int position) through the fetch (position/ Datas.size ()) The way, let Viewpager continue to play down.

Here we implement this by modifying the data source and setting the CurrentItem.

To modify a data source:

Final list<integer> datas = new arraylist<> ();
Add test data here, the actual project can be from the network to obtain data
    Datas.add (r.mipmap.welcome_page_01);
    Datas.add (r.mipmap.welcome_page_02);
    Datas.add (r.mipmap.welcome_page_03);
    Processing data source
    Datas.add (0,datas.get (Datas.size ()-1));
    Datas.add (Datas.get (1));

Setting CurrentItem needs to be done in the Onpagechangelistener object:

Mviewpager.setonpagechangelistener (New Viewpager.onpagechangelistener () {
      @Override public
      Void onpagescrolled (int position, float positionoffset, int positionoffsetpixels) {
      }
      @Override public
      Void onpageselected (int position) {
        if (position==0) {
          Mviewpager.setcurrentitem (datas.size () -2,false);
        } else if (position==datas.size ()-1) {
          mviewpager.setcurrentitem (1,false);
        }
      }
      @Override public
      void onpagescrollstatechanged (int state) {
      }
    });

Adapter is the same as the general Viewpager adapter.

How to implement an automatic loop:

Automatic loop implementation, more methods, such as Timer,handler,alarm and so on. Here we use the handle way

The custom handler class is as follows:

  public class Bannerhander extends handler{
    @Override public
    void Handlemessage (msg) {
      if (msg.what= =1) {
        Mviewpager.setcurrentitem (Mviewpager.getcurrentitem () +1);
        Sendemptymessagedelayed (1,3000);}}
  

To get the data, you can start the automatic loop after you set the adapter to Viewpager:

if (!) ( Mhandler!=null && mhandler.get ()!=null)) {
Mhandler = new Weakreference<bannerhander> (new Bannerhander ());
}
Mhandler.get (). sendemptymessagedelayed (1, 300);

Here we use a weak reference, mainly to prevent memory overflow.

Attention:

When you set up CurrentItem, you must do it in Onpagechangelistener, and the adapter finishupdate (view view) is set to display a white screen. If any great God knows, please teach.