Fragment滑动切换简单案例

2022-11-08 21:18:45

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

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