This example shares the specific code for Android to implement the infinite loop of ViewPager for your reference. The specific content is as follows
Method 1:
Implementation principle:
Suppose there are 3 pictures, 1, 2, 3, respectively, then create 5 pictures. The order of these 5 pictures is: 3, 1, 2, 3, 1, 2, 3 are the pictures we want to slide, the leftmost 3 and the rightmost 1 are the pictures we added. At the beginning, picture 1 is displayed. When the picture slides to the left, it is 1, 2, 3 in turn. When the third picture continues to slide to the left, we will add more picture 1. At this time, set the current index to the position where the real picture 1 is.
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/**
* Created by XiaoMai on 2016/10/7 17:19.
*
*/
public class LoopViewPagerDemoActivity extends BaseActivity {
/**
* Time to update the picture
*/
private static final int UPDATE_TIME = 3 * 1000;
private ViewPager mViewPager;
private LoopViewPagerAdapter mLoopViewPager;
/**
* Image resource collection
*/
private int[] mImageIds;
/**
* Picture collection
*/
private List<ImageView> mImageList;
/**
* The index of the current ad
*/
private int mCurrentPageIndex;
/**
* Instruction Point
*/
private LinearLayout mLinearLayoutPoints;
private Handler mHandler = new Handler();
@Override
protected void onCreate(Bundle savedInstanceState) {
(savedInstanceState);
}
@Override
protected void onResume() {
();
(myRunnable, UPDATE_TIME);
}
@Override
protected void onPause() {
();
(myRunnable);
}
Runnable myRunnable = new Runnable() {
@Override
public void run() {
(mCurrentPageIndex + 1);
}
};
@Override
protected void initVariables() {
();
}
@Override
protected void initViews() {
mLinearLayoutPoints = (LinearLayout) findViewById(.activity_ll_container);
mViewPager = (ViewPager) findViewById(.activity_loop_viewpager);
}
@Override
protected void loadData() {
();
(new Runnable() {
@Override
public void run() {
/**
* Initialize the resource id of the image
*/
mImageIds = new int[]{
.ic_launcher,
.ic_launcher,
.my_toast,
.my_toast};
/**
* Add ImageView
*/
mImageList = new ArrayList<>();
//Add two additional pictures int pagerCount = + 2;
layoutParams =
new (
.MATCH_PARENT,
.WRAP_CONTENT);
for (int i = 0; i < pagerCount; i++) {
ImageView imageView = new ImageView(mContext);
(layoutParams);
(imageView);
}
//Diameter of dot int diameter = Utils.dip2px(mContext,10f);
params =
new (diameter, diameter);
int margin = Utils.dip2px(mContext,5f);
(margin,margin,margin,margin);
();
for (int i = 0; i < (); i++) {
View view = new View(mContext);
(params);
if (i != 0 && i != () - 1) {
(.circle_normal);
}
(view);
}
();
(new () {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
(myRunnable);
(myRunnable, UPDATE_TIME);
mCurrentPageIndex = position;
if (position == 0) {
// When the view is in the first, set the page number to the last picture. mCurrentPageIndex = ;
} else if (position == + 1) {
// When the view is at the last, set the page number to the first picture. mCurrentPageIndex = 1;
} else {
}
/**
* When the view is in the first or last, the values of pageIndex and position are not equal.
* So you need to change the current item of viewPager.
*/
if (position != mCurrentPageIndex) {
/**
* The second parameter must be set to false, which means transitioning immediately and not giving the user a visual effect.
*/
(mCurrentPageIndex, false);
return;
}
for (int i = 1; i < () - 1; i++) {
if (i != mCurrentPageIndex){
(i).setBackgroundResource(.circle_normal);
}else {
(mCurrentPageIndex).setBackgroundResource(
.circle_select);
}
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
/**
* When the ViewPager is pressed, cancel the automatic scrolling
* On the contrary, turn on automatic sliding.
*/
(new () {
@Override
public boolean onTouch(View v, MotionEvent event) {
if(() == MotionEvent.ACTION_DOWN){
(myRunnable);
}else if (() == MotionEvent.ACTION_UP){
(myRunnable, UPDATE_TIME);
}
return false;
}
});
mLoopViewPager = new LoopViewPagerAdapter(mImageList, mImageIds);
(mLoopViewPager);
/**
* Because the 0th item is the added image, the current item must be set to 1 during initialization.
*/
(1);
dissMissProgressDialog();
}
}, 3 * 1000);
}
@Override
protected int getContentLayout() {
return .act_loopviewpager;
}
}
package ;
import .;
import ;
import ;
import ;
import ;
/**
* Created by XiaoMai on 2016/10/7 17:23.
*/
public class LoopViewPagerAdapter extends PagerAdapter {
private List<ImageView> mImageList;
private int[] mImageIds;
public LoopViewPagerAdapter(List<ImageView> mImageList, int[] mImageIds) {
= mImageList;
= mImageIds;
}
@Override
public int getCount() {
return mImageList == null ? 0 : ();
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
if (position == 0) {
// If it is the 0th item, set its image content to the last image content (position).setImageResource(mImageIds[-1]);
} else if (position == (() - 1)) {
// If it is the last item, set its image content to the first image content (position).setImageResource(mImageIds[0]);
} else {
// This is a normal picture (position).setImageResource(mImageIds[position - 1]);
}
((position));
return (position);
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
((position));
}
}
Layout file
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:andro android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <include android: layout="@layout/my_app_bar" /> <. android: android:layout_width="match_parent" android:layout_height="200dp" android:layout_below="@id/titleBar" /> <LinearLayout android: android:layout_width="match_parent" android:orientation="horizontal" android:gravity="center" android:background="@color/toast" android:layout_alignBottom="@id/activity_loop_viewpager" android:visibility="gone" android:layout_height="40dp"/> </RelativeLayout>
The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.