Android ViewPager + Fragment实现滑动页面效果

package com.cloud.viewpagerdemo;
import java.io.Serializable;
class PagerData implements Serializable {
  private int mImageResId;
  private String mContent;
  PagerData(int imageResId, String content) {
    mImageResId = imageResId;
    mContent = content;
  }
  public int getImageResId() {
    return mImageResId;
  }
  public void setImageResId(int imageResId) {
    mImageResId = imageResId;
  }
  public String getContent() {
    return mContent;
  }
  public void setContent(String content) {
    mContent = content;
  }
}

package com.cloud.viewpagerdemo;
import android.graphics.Outline;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewOutlineProvider;
import android.widget.ImageView;
import android.widget.TextView;
public class PagerFragment extends Fragment {
  private static final String ARG_DATA = "data";
  private PagerData mData;
  private ImageView mImageView;
  private TextView mContent;
  /**
   * 通过静态方法获取Fragment实例，向Fragment传参数
   * @param data 数据
   * @return Fragment
   */
  public static PagerFragment newInstance(PagerData data) {
    PagerFragment fragment = new PagerFragment();
    //使用FragmentArguments传递参数
    Bundle args = new Bundle();
    args.putSerializable(ARG_DATA, data);
    fragment.setArguments(args);
    return fragment;
  }
  @Override
  public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mData = (PagerData) getArguments().getSerializable(ARG_DATA);
  }
  @Nullable
  @Override
  public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
               @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_pager, container, false);
    //绑定控件
    mImageView = view.findViewById(R.id.image_view);
    mContent = view.findViewById(R.id.text_content);
    //ImageView设置圆角
    ViewOutlineProvider viewOutlineProvider = new ViewOutlineProvider() {
      @Override
      public void getOutline(View view, Outline outline) {
        outline.setRoundRect(0, 0, mImageView.getWidth(), mImageView.getHeight(), 16);
      }
    };
    mImageView.setOutlineProvider(viewOutlineProvider);
    mImageView.setClipToOutline(true);
    mImageView.setImageResource(mData.getImageResId());
    mContent.setText(mData.getContent());
    return view;
  }
}

package com.cloud.viewpagerdemo;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class PagerActivity extends AppCompatActivity {
  private List<PagerData> mPagerData = new ArrayList<>();
  private ViewPager mViewPager;
  private TextView mTextPage;
  private String page = "1 / 3";
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_pager);
    initData();
    FragmentManager fragmentManager = getSupportFragmentManager();
    mViewPager = findViewById(R.id.view_pager);
    mTextPage = findViewById(R.id.text_page);
    //设置ViewPager适配器
    mViewPager.setAdapter(new FragmentStatePagerAdapter(fragmentManager) {
      @Override
      public Fragment getItem(int position) {
        return PagerFragment.newInstance(mPagerData.get(position));
      }
      @Override
      public int getCount() {
        return mPagerData.size();
      }
    });
    //监听页面改变
    mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
      @Override
      public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
      }
      @Override
      public void onPageSelected(int position) {
        //页面选中
        page = String.valueOf(position + 1) + " / " + String.valueOf(mPagerData.size());
        mTextPage.setText(page);
      }
      @Override
      public void onPageScrollStateChanged(int state) {
      }
    });
    //设置缓存页数
    mViewPager.setOffscreenPageLimit(3);
    //设置默认页
    mViewPager.setCurrentItem(0);
    mTextPage.setText(page);
  }
  private void initData() {
    //添加三项数据
    mPagerData.add(new PagerData(R.drawable.img_0, "Photo by Adam Krowitz"));
    mPagerData.add(new PagerData(R.drawable.img_1, "Photo by Samuel Ferrara"));
    mPagerData.add(new PagerData(R.drawable.img_2, "Photo by Earth"));
  }
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginBottom="32dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:background="@drawable/pager_background"
    android:elevation="4dp"
    android:orientation="vertical"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent">
    <ImageView
      android:id="@+id/image_view"
      android:layout_width="match_parent"
      android:layout_height="0dp"
      android:layout_margin="8dp"
      android:layout_weight="1"
      android:contentDescription="@null"
      android:scaleType="centerCrop" />
    <TextView
      android:id="@+id/text_content"
      android:layout_width="match_parent"
      android:layout_height="125dp"
      android:gravity="center"
      android:padding="8dp"
      android:textSize="18sp"
      android:textColor="#000000"
      tools:text="Content" />
  </LinearLayout>
</android.support.constraint.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context=".PagerActivity">
  <android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="48dp"
    android:background="@color/colorPrimary"
    android:elevation="4dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent">
    <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="center"
      android:textSize="18sp"
      android:textColor="#FFFFFF"
      android:text="@string/app_name" />
  </android.support.v7.widget.Toolbar>
  <android.support.v4.view.ViewPager
    android:id="@+id/view_pager"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/toolbar">
  </android.support.v4.view.ViewPager>
  <TextView
    android:id="@+id/text_page"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="4dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="@+id/toolbar"
    tools:text="page" />
</android.support.constraint.ConstraintLayout>