Fragment滑动切换简单案例

Fragment的产生与介绍Android运行在各种各样的设备中，有小屏幕的手机，超大屏的平板甚至电视。针对屏幕尺寸的差距，很多情况下，都是先针对手机开发一套App，然后拷贝一份，修改布局以适应平板神马超级大屏的。难道无法做到一个App可以同时适应手机和平板么，当然了，必须有啊。Fragment的出现就是为了解决这样的问题。你可以把Fragment当成Activity的一个界面的一个组成部分，甚至Activity的界面可以完全有不同的Fragment组成，更帅气的是Fragment拥有自己的生命周期和接收、处理用户的事件，这样就不必在Activity写一堆控件的事件处理的代码了。更为重要的是，你可以动态的添加、替换和移除某个Fragment

实例图片：

MainActivity

package com.shaoxin.myfragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.widget.RadioGroup;

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

public class MainActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener {
    private FragmentManager fragment;
    private RadioGroup radioGroup;
    private FragmentTransaction fragmentTransaction;
    private FirstFragment firstFragment;
    private SecondFragment secondFragment;
    private ThirdFragment thirdFragment;
    private ViewPager viewpager;
    MyAdpter myAdpter;
    private List<Fragment> list;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取管理工具
        fragment = getSupportFragmentManager();
        radioGroup = (RadioGroup) findViewById(R.id.radio_group);
        viewpager = (ViewPager) findViewById(R.id.viewpager);
        //实例化fragment
        firstFragment = new FirstFragment();
        secondFragment = new SecondFragment();
        thirdFragment = new ThirdFragment();
        list = new ArrayList<>();
        list.add(firstFragment);
        list.add(secondFragment);
        list.add(thirdFragment);
        myAdpter = new MyAdpter(fragment);
        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                //开启事务
//                fragmentTransaction = fragment.beginTransaction();
                switch (checkedId) {
                    case R.id.radio_masg:
                        //替换填充view
//                        fragmentTransaction.replace(R.id.viewpager, firstFragment);
                        viewpager.setCurrentItem(0);
                        break;
                    case R.id.radio_imag:
                        viewpager.setCurrentItem(1);
//                        fragmentTransaction.replace(R.id.viewpager, secondFragment);
                        break;
                    case R.id.radio_setting:
                        viewpager.setCurrentItem(2);
//                        fragmentTransaction.replace(R.id.viewpager, thirdFragment);
                        break;
                }
                //提交数据
//                fragmentTransaction.commit();
            }
        });
        viewpager.setAdapter(myAdpter);
        viewpager.addOnPageChangeListener(this);
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    @Override
    public void onPageSelected(int position) {
        switch (position) {
            case 0:
                radioGroup.check(R.id.radio_masg);
                break;
            case 1:
                radioGroup.check(R.id.radio_imag);
                break;
            case 2:
                radioGroup.check(R.id.radio_setting);
                break;
        }
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }

    public class MyAdpter extends FragmentPagerAdapter {


        public MyAdpter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            return list.get(position);
        }

        @Override
        public int getCount() {
            return list.size();
        }
    }
}

FirstFragment

package com.shaoxin.myfragment;

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;

/**
 * Created by shaoxin on 2016/12/11.
 */

public class FirstFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        container = (ViewGroup) inflater.inflate(R.layout.first_fragment, null);
        return container;
    }
}

SecondFragment

package com.shaoxin.myfragment;

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;

/**
 * Created by shaoxin on 2016/12/11.
 */

public class SecondFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        container = (ViewGroup) inflater.inflate(R.layout.sec_fragment, null);
        return container;
    }
}

ThirdFragment

package com.shaoxin.myfragment;

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;

/**
 * Created by shaoxin on 2016/12/11.
 */

public class ThirdFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        container = (ViewGroup) inflater.inflate(R.layout.third_fragment, null);
        return container;
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.shaoxin.myfragment.MainActivity">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <RadioGroup
        android:id="@+id/radio_group"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:orientation="horizontal">

        <RadioButton
            android:id="@+id/radio_masg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:button="@null"
            android:drawableTop="@drawable/button_background"
            android:gravity="center_horizontal"
            android:text="消息" />

        <RadioButton
            android:id="@+id/radio_imag"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:button="@null"
            android:drawableTop="@drawable/button_background"
            android:gravity="center_horizontal"
            android:text="图片" />

        <RadioButton
            android:id="@+id/radio_setting"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:button="@null"
            android:drawableTop="@drawable/button_background"
            android:gravity="center_horizontal"
            android:text="设置" />
    </RadioGroup>


</FrameLayout>

first_fragment.xml

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

sec_fragment.xml

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

third_fragment.xml

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

然后再drawable文件夹中创建文件button_background.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@android:drawable/star_on" android:state_checked="true" />
    <item android:drawable="@android:drawable/star_off" android:state_checked="false" />
</selector>

另外的图片自行插入