Android新手开发之旅-ViewPager+Fragment实现页面的切换

liu

ViewPager+Fragment实现页面的切换




平时开发中一般都是ViewPager和Fragment一起来使用，这次来简单模仿实现下微信的主界面的切换效果

首先先建四个Fragment(HomeFragment,ContactsFragment,DiscoverFragment,MyFragment),只在布局中放入一个TextView，不做其他的操作，这里只以其中一个布局举例：


fragment_home.xml:

[XML] 纯文本查看 复制代码

<FrameLayout 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.company.helloworld.firstapplication.HomeFragment">

    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="第一个Fragment"
        />

</FrameLayout>

然后设置主布局，添加viewpager
主布局activity_main.xml:

[XML] 纯文本查看 复制代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v4.view.ViewPager
        android:id="@+id/vp"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <include layout="@layout/layout_bottom" />
</LinearLayout>

layout_bottom:

[XML] 纯文本查看 复制代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:orientation="horizontal">

        <LinearLayout
            android:id="@+id/layout_home"
            style="@style/layout">

            <ImageView
                android:id="@+id/iv_home"
                style="@style/image"
                android:src="@drawable/home_on" />

            <TextView
                android:id="@+id/tv_home"
                style="@style/textview"
                android:textColor="#00c800"
                android:text="微信" />
        </LinearLayout>

        <LinearLayout
            android:id="@+id/layout_contacts"
            style="@style/layout">

            <ImageView
                android:id="@+id/iv_contacts"
                style="@style/image"
                android:src="@drawable/contacts_off" />

            <TextView
                android:id="@+id/tv_contacts"
                style="@style/textview"
                android:text="联系人" />
        </LinearLayout>

        <LinearLayout
            android:id="@+id/layout_discover"
            style="@style/layout">

            <ImageView
                android:id="@+id/iv_discover"
                style="@style/image"
                android:src="@drawable/discover_off" />

            <TextView
                android:id="@+id/tv_discover"
                style="@style/textview"
                android:text="发现" />
        </LinearLayout>

        <LinearLayout
            android:id="@+id/layout_my"
            style="@style/layout">

            <ImageView
                android:id="@+id/iv_my"
                style="@style/image"
                android:src="@drawable/my_off" />

            <TextView
                android:id="@+id/tv_my"
                style="@style/textview"
                android:text="我" />
        </LinearLayout>

    </LinearLayout>
</LinearLayout>

style.xml:

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<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="layout">
        <item name="android:layout_width">0dp</item>
        <item name="android:layout_height">match_parent</item>
        <item name="android:layout_weight">1</item>
        <item name="android:orientation">vertical</item>
        <item name="android:gravity">center</item>
    </style>

    <style name="image">
        <item name="android:layout_width">30dp</item>
        <item name="android:layout_height">30dp</item>
    </style>

    <style name="textview">
        <item name="android:layout_height">wrap_content</item>
        <item name="android:layout_width">wrap_content</item>
        <item name="android:textSize">14sp</item>
        <item name="android:textColor">@android:color/black</item>
    </style>
</resources>

最后将新建的Fragment添加到集合中，设置适配器
MainActivity:

[Java] 纯文本查看 复制代码

package com.company.helloworld.firstapplication;

import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends FragmentActivity implements View.OnClickListener {
    private LinearLayout layout_home;
    private LinearLayout layout_contacts;
    private LinearLayout layout_discover;
    private LinearLayout layout_my;
    private ImageView iv_home;
    private ImageView iv_contacts;
    private ImageView iv_discover;
    private ImageView iv_my;
    private TextView tv_home;
    private TextView tv_contacts;
    private TextView tv_discover;
    private TextView tv_my;
    private List<Fragment> list;
    private ViewPager viewPager;

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

        initView();
    }

    private void initView() {
        //初始化控件
        viewPager = findViewById(R.id.vp);
        layout_home = findViewById(R.id.layout_home);
        layout_contacts = findViewById(R.id.layout_contacts);
        layout_discover = findViewById(R.id.layout_discover);
        layout_my = findViewById(R.id.layout_my);
        iv_home = findViewById(R.id.iv_home);
        iv_contacts = findViewById(R.id.iv_contacts);
        iv_discover = findViewById(R.id.iv_discover);
        iv_my = findViewById(R.id.iv_my);
        tv_home = findViewById(R.id.tv_home);
        tv_contacts = findViewById(R.id.tv_contacts);
        tv_discover = findViewById(R.id.tv_discover);
        tv_my = findViewById(R.id.tv_my);
        layout_home.setOnClickListener(this);
        layout_contacts.setOnClickListener(this);
        layout_discover.setOnClickListener(this);
        layout_my.setOnClickListener(this);

        //创建数据源
        list = new ArrayList<>();
        HomeFragment homeFragment = new HomeFragment();
        ContactsFragment contactsFragment = new ContactsFragment();
        DiscoverFragment discoverFragment = new DiscoverFragment();
        MyFragment myFragment = new MyFragment();
        list.add(homeFragment);
        list.add(contactsFragment);
        list.add(discoverFragment);
        list.add(myFragment);

        //设置适配器
        FragmentManager manager = getSupportFragmentManager();
        MyAdapter adapter = new MyAdapter(manager, list);
        viewPager.setAdapter(adapter);
    }

    //设置成为选择状态
    private void initColor() {
        iv_home.setImageResource(R.drawable.home_off);
        tv_home.setTextColor(Color.BLACK);
        iv_contacts.setImageResource(R.drawable.contacts_off);
        tv_contacts.setTextColor(Color.BLACK);
        iv_discover.setImageResource(R.drawable.discover_off);
        tv_discover.setTextColor(Color.BLACK);
        iv_my.setImageResource(R.drawable.my_off);
        tv_my.setTextColor(Color.BLACK);
    }

    @Override
    public void onClick(View view) {
        initColor();
        switch (view.getId()) {
            case R.id.layout_home:
                iv_home.setImageResource(R.drawable.home_on);
                tv_home.setTextColor(Color.parseColor("#00c800"));
                //设置viewpager显示哪一页，索引从0开始
                viewPager.setCurrentItem(0);
                break;
            case R.id.layout_contacts:
                iv_contacts.setImageResource(R.drawable.contacts_on);
                tv_contacts.setTextColor(Color.parseColor("#00c800"));
                viewPager.setCurrentItem(1);
                break;
            case R.id.layout_discover:
                iv_discover.setImageResource(R.drawable.discover_on);
                tv_discover.setTextColor(Color.parseColor("#00c800"));
                viewPager.setCurrentItem(2);
                break;
            case R.id.layout_my:
                iv_my.setImageResource(R.drawable.my_on);
                tv_my.setTextColor(Color.parseColor("#00c800"));
                viewPager.setCurrentItem(3);
                break;
        }
    }
}

MyAdapter:

[Java] 纯文本查看 复制代码

package com.company.helloworld.firstapplication;
    
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentManager;
    import android.support.v4.app.FragmentPagerAdapter;
    
    import java.util.List;
    
    /**
     * Created by Administrator on 2018/12/17.
     */
    
    public class MyAdapter extends FragmentPagerAdapter {
        private List<Fragment> list;
    
        public MyAdapter(FragmentManager fm, List<Fragment> fragments) {
            super(fm);
            this.list = fragments;
        }
    
        //返回第几个fragment
        @Override
        public Fragment getItem(int position) {
            return list.get(position);
        }
    
        //总共有多少个fragment
        @Override
        public int getCount() {
            return list.size();
        }
    }

看下运行效果：


        

Amy

真是难得给力的帖子啊。