viewPager的简单实现

首先是布局

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"              android:layout_width="match_parent"              android:layout_height="match_parent"              android:orientation="vertical">    <android.support.v4.view.ViewPager        android:id="@+id/vp_guide"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:layout_alignParentLeft="true"        android:layout_alignParentTop="true">    android.support.v4.view.ViewPager>RelativeLayout>

activity代码

public class GuideActivity extends AppCompatActivity {    private int[] imageIds = new int[] {R.mipmap.guide_1, R.mipmap.guide_2, R.mipmap.guide_3};//图片数组    private ViewPager vpGuide;    private LinearLayout llContainer;    private ImageView ivRedDot;    private Button btnNext;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_guide);        initView();        MyPagerAdapter myPagerAdapter = new MyPagerAdapter();        vpGuide.setAdapter(myPagerAdapter);//别忘了设置适配器    }    /** 初始化控件 **/    private void initView() {        vpGuide = (ViewPager) findViewById(R.id.vp_guide);    }    private class MyPagerAdapter extends PagerAdapter{        /** 返回界面viewPager返回个数 **/        @Override        public int getCount() {            return imageIds.length;        }        @Override        public boolean isViewFromObject(View view, Object object) {            return view == object;        }        /** 给viewPager添加一个界面的方法 **/        @Override        public Object instantiateItem(ViewGroup container, int position) {            //1.准备添加的图片            ImageView imageView = new ImageView(getApplicationContext());            imageView.setBackgroundResource(imageIds[position]);            //2.向viewPager添加图片            container.addView(imageView);            //3.如果添加的内容要展示,一定要将添加的对象返回出去            return imageView;        }        /** 从ViewPager删除一个界面的方法  为了防止oom  out of memory**/        @Override        public void destroyItem(ViewGroup container, int position, Object object) {            container.removeView((View) object);            //需要删除的异常   super.destroyItem(container, position, object);        }    }}

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