android开发分享Android 使用viewpager实现画廊式效果（展示图片）

先看一下效果

1.创建一个自定义类 ZoomOutPageTransformer

 public class ZoomOutPageTransformer implements ViewPager.PageTransformer {     //自由控制缩放比例     private static final float MAX_SCALE = 1f;     private static final float MIN_SCALE = 0.8f;//0.85f      @Override     public void transformPage(View page, float position) {          if (position <= 1) {              float scaleFactor = MIN_SCALE + (1 - Math.abs(position)) * (MAX_SCALE - MIN_SCALE);              page.setScaleX(scaleFactor);              if (position > 0) {                 page.setTranslationX(-scaleFactor * 2);             } else if (position < 0) {                 page.setTranslationX(scaleFactor * 2);             }             page.setScaleY(scaleFactor);         } else {              page.setScaleX(MIN_SCALE);             page.setScaleY(MIN_SCALE);         }     } } 

2.创建适配器  MyAdapter

 public class MyAdapter extends PagerAdapter {      private int[] mData;     private Context mContext;      public MyAdapter(Context ctx, int[] data) {         this.mContext = ctx;         this.mData = data;     }      @Override     public int getCount() {         return mData.length;// 返回数据的个数     }      @Override     public Object instantiateItem(final ViewGroup container, final int position) {//子View显示         View view = View.inflate(container.getContext(), R.layout.item, null);         ImageView imageView = view.findViewById(R.id.iv_icon);         imageView.setImageResource(mData[position]);          imageView.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 Toast.makeText(mContext, "当前条目：" + position, Toast.LENGTH_SHORT).show();             }         });          container.addView(view);//添加到父控件         return view;     }      @Override     public boolean isViewFromObject(View view, Object object) {         return view == object;// 过滤和缓存的作用     }      @Override     public void destroyItem(ViewGroup container, int position, Object object) {         container.removeView((View) object);//从viewpager中移除掉     } }

3.item布局

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:layout_width="match_parent"     android:layout_height="match_parent">     <ImageView         android:id="@+id/iv_icon"         android:layout_width="match_parent"         android:scaleType="centerCrop"         android:src="@mipmap/ic_launcher"         android:layout_height="match_parent"/> </LinearLayout>

4.activity_main布局

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     android:id="@+id/ll_layout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:clipChildren="false"     android:orientation="vertical">      <TextView         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:gravity="center"         android:padding="5dp"         android:text="viewpager实现画廊效果"         android:textColor="@color/colorPrimary"/>      <androidx.viewpager.widget.ViewPager         android:id="@+id/viewPager"         android:layout_width="200dp"         android:layout_height="300dp"         android:layout_gravity="center"         android:layout_marginBottom="30dp"         android:clipChildren="false"         android:layout_marginTop="30dp"/> </LinearLayout>

5.Main_Activity

 public class MainActivity extends AppCompatActivity {     private ViewPager mViewPager;     private LinearLayout ll_layout;      //向导界面的图片     private int[] mPics = new int[]{R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.mipmap.ic_launcher};      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         initView();     }      private void initView() {         mViewPager = (ViewPager) findViewById(R.id.viewPager);         ll_layout = (LinearLayout) findViewById(R.id.ll_layout);          //设置适配器         mViewPager.setAdapter(new MyAdapter(this, mPics));         mViewPager.setPageMargin(20);         mViewPager.setOffscreenPageLimit(mPics.length);         mViewPager.setPageTransformer(true, new ZoomOutPageTransformer());//设置画廊模式          //左右都有图         mViewPager.setCurrentItem(1);          //viewPager左右两边滑动无效的处理         ll_layout.setOnTouchListener(new View.OnTouchListener() {             @Override             public boolean onTouch(View view, MotionEvent motionEvent) {                 return mViewPager.dispatchTouchEvent(motionEvent);             }         });     } }