ViewPager添加小圆点

Posted 2020-09-26 新年新气象934060369

ViewPager添加小圆点很简单，但是如果是网络图片可能就不太好做了，所以我这里给出一种方法，当然你也可以用其他的

 

 

1.主界面xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context="com.cqytjr.www.cheji.Activity.BigImageActivity">


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






    </android.support.v4.view.ViewPager>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:id="@+id/ll_pager_num"
        android:orientation="horizontal"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="45dp"
        android:layout_centerHorizontal="true"
        >



    </LinearLayout>



</RelativeLayout>

 activity代码：

public class BigImageActivity extends BaseActivity {

    private ViewPager pager;
    private List <ImageView>list;
    private LinearLayout mNumLayout;
    private List<Button>pagerList;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_big_image);
        initView();
    }

    @Override
    protected void initView() {
        super.initView();

        initWithData();


        mNumLayout = (LinearLayout) findViewById(R.id.ll_pager_num);
        pagerList = new ArrayList<Button>();

        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_page_indicator);
        for (int i = 0; i < list.size(); i++) {
            Button bt = new Button(this);
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));


           //为小圆点左右添加间距
            params.leftMargin = 10;
            params.rightMargin = 10;
            //手动给小圆点一个大小
            params.height = bitmap.getWidth();
            params.width = bitmap.getHeight();


//            bt.setLayoutParams(new ViewGroup.LayoutParams(bitmap.getWidth(),bitmap.getHeight()));
//            bt.setBackgroundResource(R.drawable.ic_page_indicator);
            mNumLayout.addView(bt,params);
            pagerList.add(bt);
        }
        pager = (ViewPager)findViewById(R.id.viewpager);


        PagerAdapter adapter = new PagerAdapter() {
            @Override
            public int getCount() {
                return list.size();
            }

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

            @Override
            public Object instantiateItem(ViewGroup container, int position)
            {

                container.addView(list.get(position));

                return list.get(position);
            }

            @Override
            public void destroyItem(ViewGroup container, int position,
                                    Object object)
            {

                container.removeView(list.get(position));
            }


        };



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

            }

            @Override
            public void onPageSelected(int position) {
                choseItem(position);
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

        pager.setAdapter(adapter);
        pager.setCurrentItem(0);
        choseItem(0);


    }
    public void initWithData(){

        int[]strings = {R.drawable.ic_test_0,R.drawable.ic_test_1,R.drawable.ic_test_2,
                R.drawable.ic_test_3,R.drawable.ic_test_4,R.drawable.ic_test_5,R.drawable.ic_test_6};

        list = new ArrayList<ImageView>();
        for (int i=0;i<strings.length;i++){

            ImageView imageView = new ImageView(getApplicationContext());
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setImageResource(strings[i]);
            list.add(imageView);
        }

    }


    private void choseItem(int i){

        Log.d("BigImageActivity",i+"===========");

        for (Button button:pagerList){
            button.setBackgroundResource(R.drawable.ic_page_indicator);
        }
        Button button = pagerList.get(i);
        button.setBackgroundResource(R.drawable.ic_page_indicator_focused);

    }








}