简单的ViewPager+Fragment+小圆点的实现

红点(http://img.blog.csdn.net/20170926151350811?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvUm9va2llemJi/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
白点(http://img.blog.csdn.net/20170926151431837?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvUm9va2llemJi/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)

首先是布局：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout 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="com.bawei.lx_lxtwo.MainActivity">   <android.support.v4.view.ViewPager       android:id="@+id/vp"       android:layout_width="match_parent"       android:layout_height="match_parent"       android:layout_alignParentTop="true"       android:layout_alignParentStart="true">   </android.support.v4.view.ViewPager>   <LinearLayout       android:layout_alignParentBottom="true"       android:layout_centerHorizontal="true"       android:layout_marginBottom="10dp"       android:orientation="horizontal"       android:layout_width="wrap_content"       android:layout_height="wrap_content">      <ImageView          android:id="@+id/img1"          android:src="@drawable/point_selected"           android:layout_marginRight="5dp"          android:layout_width="wrap_content"          android:layout_height="wrap_content" />      <ImageView          android:id="@+id/img2"          android:layout_marginLeft="5dp"          android:src="@drawable/point_mormal"          android:layout_width="wrap_content"          android:layout_height="wrap_content" />   </LinearLayout></RelativeLayout>

然后我们新建两个fragment

package com.bawei.lx_lxtwo.fragments;import android.os.Bundle;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.widget.TextView;import com.bawei.lx_lxtwo.R;/** * Created by Zhang on 2017/9/26. */public class HelloFragment extends Fragment {    private View view;    private TextView mHelloTv;    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        View v = inflater.inflate(R.layout.hello, container, false);        initView(v);        mHelloTv.setText("    欢迎使用\n北京共享单车");        return v;    }    private void initView(View v) {        mHelloTv = (TextView) v.findViewById(R.id.hello_tv);    }}

fragment的布局里只有一个textview，再建一个一样的。
然后就是mainactivity

package com.bawei.lx_lxtwo;import android.os.Bundle;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentPagerAdapter;import android.support.v4.view.ViewPager;import android.support.v7.app.AppCompatActivity;import android.widget.ImageView;import com.bawei.lx_lxtwo.fragments.GoFragment;import com.bawei.lx_lxtwo.fragments.HelloFragment;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    private ViewPager mVp;    private List<Fragment> flist = new ArrayList<>();    private ImageView[] imgs;    private ImageView mImg1;    private ImageView mImg2;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //初始化数据        initView();        //设置数据        getview();        imgs = new ImageView[]{mImg1,mImg2};    }    private void getview() {        flist.add(new HelloFragment());        flist.add(new GoFragment());        mVp.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {            @Override            public Fragment getItem(int position) {                return flist.get(position);            }            @Override            public int getCount() {                return flist.size();            }        });    //这里用viewpager的OnPageChangeListener方法设置小圆点的颜色        mVp.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {            @Override            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {            }            @Override            public void onPageSelected(int position) {                getpoint(position);            }            @Override            public void onPageScrollStateChanged(int state) {            }        });    }    private void getpoint(int index) {    //这里判断哪个是红点        for (int i = 0; i < imgs.length; i++) {            if(i==index){                imgs[i].setImageResource(R.drawable.point_selected);            }else{                imgs[i].setImageResource(R.drawable.point_mormal);            }        }    }    private void initView() {        mVp = (ViewPager) findViewById(R.id.vp);        mImg1 = (ImageView) findViewById(R.id.img1);        mImg2 = (ImageView) findViewById(R.id.img2);    }}