安卓视图翻页器如何在几秒钟后自动切换页面

Question

我已经使用了Android的ViewPager来显示图片和文字，现在我想实现的是如果用户不主动滑动图片，则在几秒钟后自动更换图片，但当用户再次使用手指滑动时，图片就不会自动更换了。

我尝试使用Handler来创建延迟，但它对我没有起作用。

请帮帮我。

public class SimpleImageViewerActivity  extends Activity implements ViewPager.OnPageChangeListener{
    private Handler handler;
    ViewPager myPager;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.imageslideshow);
        MyPagerAdapter adapter = new MyPagerAdapter();
        myPager = (ViewPager) findViewById(R.id.slideShowPager);
        myPager.setAdapter(adapter);
        myPager.setCurrentItem(0);

        handler = new Handler();
    myPager.setOnPageChangeListener(this);
    }

    private class MyPagerAdapter extends PagerAdapter {

        public int getCount() {
            return 5;
        }

        public Object instantiateItem(View collection, int position) {

            LayoutInflater inflater = (LayoutInflater) collection.getContext()
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            int resId = 0;
            switch (position) {
            case 0:
                resId = R.layout.farleft;
                break;
            case 1:
                resId = R.layout.left;
                break;
            case 2:
                resId = R.layout.middle;
                break;
            case 3:
                resId = R.layout.right;
                break;
            case 4:
                resId = R.layout.farright;
                break;
            }

            View view = inflater.inflate(resId, null);

            ((ViewPager) collection).addView(view, 0);

            return view;
        }

        @Override
        public void destroyItem(View arg0, int arg1, Object arg2) {
            ((ViewPager) arg0).removeView((View) arg2);

        }

        @Override
        public void finishUpdate(View arg0) {
            // TODO Auto-generated method stub

        }

        @Override
        public boolean isViewFromObject(View arg0, Object arg1) {
            return arg0 == ((View) arg1);

        }

        @Override
        public void restoreState(Parcelable arg0, ClassLoader arg1) {
            // TODO Auto-generated method stub

        }

        @Override
        public Parcelable saveState() {
            // TODO Auto-generated method stub
            return null;
        }

        @Override
        public void startUpdate(View arg0) {
            // TODO Auto-generated method stub

        }


    }

    @Override
    public void onPageScrollStateChanged(int arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onPageScrolled(int arg0, float arg1, int arg2) {
        // TODO Auto-generated method stub

        updateUI(arg2);
    }

    @Override
    public void onPageSelected(int arg0) {
        // TODO Auto-generated method stub
        //updateUI(arg0);

    }

    public void onNothingSelected(AdapterView<?> adapterView) {    
        final int i =0;
        adapterView.postDelayed(new Runnable(){

            @Override
            public void run() {
                // TODO Auto-generated method stub
                updateUI(i);            
            }

        }, 5000);
        Toast.makeText(this, "In nothing selected method",Toast.LENGTH_SHORT).show();




    }

    private void updateUI(final int fi) {
           /* handler.post(new Runnable() {
                public void run() {
                    gallery.setSelection(i);
                    viewPager.setCurrentItem(i);

                    //textView.setText("Photo #" + i);
                }
            });*/
            handler.postDelayed(new Runnable() {
                public void run() {
                    int i=fi;
                    int j = i;
                    myPager.setCurrentItem(j++);
                    System.out.println("Hello");             

                }
            },1000);
        }   


}

- Osama.070032

---

尝试使用ViewSwitcher。设计您的页面并在几秒钟后调用其next()方法。 - Suvam Roy

请您提供一个例子或者代码片段好吗？ - Osama.070032

嘿，伙计，我已经实现了这个场景，如果你需要的话，请告诉我，我会在这里发布解决方案。 - krisDrOid

@krisDrOid，您能否在此处发布使用ViewPager的解决方案？ - Rasmus

Answer 1

使用javautil计时器并设置一个，在计时器结束时可以使用。

class UpdateTimeTask extends TimerTask {
   public void run() {
    //Code for the viewPager to change view
  }
 }


 // Code to schedule the timer
 timer = new Timer();
 timer.schedule(new UpdateTimeTask(), 100, 200);

希望这能帮到你，使用安卓文档查找确切的API调用。

<ViewPager>.setCurrentitem(i++%<MaxViews>)

- Ajay

---

尝试在onCreate（activity）中执行此操作，出现了java.lang.IllegalStateException：必须从进程的主线程调用。:/ - GuilhE

请看这个 stackoverflow 上的答案：https://dev59.com/gWMm5IYBdhLWcg3wburb#17612369 - Shajeel Afzal

Answer 2

就UI更新而言，您可以通过处理程序完成。因此，在timertask类中调用处理程序，您可以执行以下操作：

Timer timer=null;
static int time_tomove = 0;

class UpdateTimeTask extends TimerTask {
       public void run() {
        //Code for the viewPager to change view
           System.out.println("The value of the time_tomove ");
           time_tomove++;
           Message msg = handler_timer.obtainMessage();
            Bundle b = new Bundle();
            b.putInt("time", time_tomove);
            msg.setData(b);
            handler_timer.sendMessage(msg);
      }
     }




public static Handler handler_timer = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
    magazineHolder.setCurrentItem(time_tomove);
    }
};

在完成这个步骤后，你可以在onresume或oncreate()方法中调用以下两行代码：

timer = new Timer();
         timer.schedule(new UpdateTimeTask(), 100, 2000);

- Devavrata

Answer 3

Kotlin方式

这是从Fragment上下文中的代码，如果在Activity中，则删除requireActivity()

private var timer: Timer? = null
private var page = 0
private var maxPages = 4

   // Use this method to setup your viewpager in your onCreate() or onActivityCreated() methods
   fun setupViewPager(){
    viewPager2.adapter = MyAdapter()
    viewPager2.isUserInputEnabled = false
    pageSwitcher(5)
}

fun pageSwitcher(seconds: Int) {
    timer = Timer()
    timer!!.scheduleAtFixedRate(RemindTask(), 0, seconds * 1000.toLong())
}

class RemindTask:TimerTask(){

        override fun run() {
            requireActivity().runOnUiThread {
                if(page == maxPages){
                    page = 0
                }else{
                    viewPager2.setCurrentItem(page++,true)
                }
            }
        }
    }

- Gastón Saillén