Fragment创建添加切换和对应底部导航（二）

目标：可以滑动Fragment来导航。

原来是通过FragmentManager添加Fragment后，show和hide来显示和隐藏Fragment。

这里使用Viewpager和FragmentPagerAdapter来实现。

把activity_main.xml中的FrameLayout改成ViewPager

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

全部activity_main.xml文件代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical">

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

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="55dp">

        <View
            android:layout_width="wrap_content"
            android:layout_height="1dp"
            android:background="?android:listDivider"
            />
        <LinearLayout
            android:layout_width="match_parent"
            android:orientation="horizontal"
            android:background="@android:color/white"
            android:layout_height="54dp">

            <LinearLayout
                android:id="@+id/ll_home"
                android:layout_width="0dp"
                android:padding="4dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:gravity="center"
                android:orientation="vertical">

                <ImageView
                    android:id="@+id/iv_home"
                    android:layout_width="28dp"
                    android:layout_height="28dp"
                    android:src="@drawable/bid02"
                    tools:ignore="ContentDescription" />

                <TextView
                    android:id="@+id/tv_home"
                    android:textColor="@color/home_back_unselected"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="首页"
                    android:layout_marginTop="2dp"
                    android:textSize="14sp"/>
            </LinearLayout>
            <LinearLayout
                android:id="@+id/ll_invest"
                android:layout_width="0dp"
                android:padding="4dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:gravity="center"
                android:orientation="vertical">

                <ImageView
                    android:id="@+id/iv_invest"
                    android:layout_width="28dp"
                    android:layout_height="28dp"
                    android:src="@drawable/bid04" />

                <TextView
                    android:id="@+id/tv_invest"
                    android:textColor="@color/home_back_unselected"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="二页"
                    android:layout_marginTop="2dp"
                    android:textSize="14sp"/>
            </LinearLayout>
            <LinearLayout
                android:id="@+id/ll_me"
                android:layout_width="0dp"
                android:padding="4dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:gravity="center"
                android:orientation="vertical">

                <ImageView
                    android:id="@+id/iv_me"
                    android:layout_width="28dp"
                    android:layout_height="28dp"
                    android:src="@drawable/bid06" />

                <TextView
                    android:id="@+id/tv_me"
                    android:textColor="@color/home_back_unselected"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="三页"
                    android:layout_marginTop="2dp"
                    android:textSize="14sp"/>
            </LinearLayout>-
            <LinearLayout
                android:id="@+id/ll_more"
                android:layout_width="0dp"
                android:padding="4dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:gravity="center"
                android:orientation="vertical">

                <ImageView
                    android:id="@+id/iv_more"
                    android:layout_width="28dp"
                    android:layout_height="28dp"
                    android:src="@drawable/bid08" />

                <TextView
                    android:id="@+id/tv_more"
                    android:textColor="@color/home_back_unselected"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="四页"
                    android:layout_marginTop="2dp"
                    android:textSize="14sp"/>
            </LinearLayout>

        </LinearLayout>
        </LinearLayout>
</LinearLayout>

在MainActivity中，获取ViewPager对象

@BindView(R.id.viewPager)
ViewPager viewPager;

InitFragments函数去掉FragmentManager添加的代码，使用适配器。

    private void InitFragments() {
        fragments.clear();

        if (fragmentA == null) {
            fragmentA = new FragmentA();
        }
        if (fragmentB == null) {
            fragmentB = new FragmentB();
        }
        if (fragmentC == null) {
            fragmentC = new FragmentC();
        }
        if (fragmentD == null) {
            fragmentD = new FragmentD();
        }
        fragments.add(fragmentA);
        fragments.add(fragmentB);
        fragments.add(fragmentC);
        fragments.add(fragmentD);

        TabPageAdapter adapter = new TabPageAdapter(getSupportFragmentManager(), fragments);
        viewPager.setAdapter(adapter);
        //滑动响应接口实现
        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                selectNavigation(position);
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
    }

适配器类的代码

    class TabPageAdapter extends FragmentPagerAdapter {
        private List<Fragment> fragments;
        public TabPageAdapter(FragmentManager fm,List<Fragment> fragments) {
            super(fm);
            this.fragments=fragments;
        }

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

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

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            super.destroyItem(container, position, object);
        }
    }

selectNavigaton也需要对切换Fragment，原来显示和隐藏Fragment，现在不适用了，改成

viewPager.setCurrentItem(page,true);

MainActivity全部代码

package com.utopia.testfragment;

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.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

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

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class MainActivity extends FragmentActivity {


    FragmentA fragmentA;
    FragmentB fragmentB;
    FragmentC fragmentC;
    FragmentD fragmentD;
    List<Fragment> fragments = new ArrayList<Fragment>();

    @BindView(R.id.iv_home)
    ImageView ivHome;
    @BindView(R.id.tv_home)
    TextView tvHome;
    @BindView(R.id.ll_home)
    LinearLayout llHome;
    @BindView(R.id.iv_invest)
    ImageView ivInvest;
    @BindView(R.id.tv_invest)
    TextView tvInvest;
    @BindView(R.id.ll_invest)
    LinearLayout llInvest;
    @BindView(R.id.iv_me)
    ImageView ivMe;
    @BindView(R.id.tv_me)
    TextView tvMe;
    @BindView(R.id.ll_me)
    LinearLayout llMe;
    @BindView(R.id.iv_more)
    ImageView ivMore;
    @BindView(R.id.tv_more)
    TextView tvMore;
    @BindView(R.id.ll_more)
    LinearLayout llMore;
    @BindView(R.id.viewPager)
    ViewPager viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        InitFragments();
        System.out.println("init DONE....................");
        selectNavigation(0);


    }

    @OnClick({R.id.ll_home, R.id.ll_invest, R.id.ll_me, R.id.ll_more})
    public void changeTab(View view) {
        switch (view.getId()) {
            case R.id.ll_home:
                selectNavigation(0);
                break;
            case R.id.ll_invest:
                selectNavigation(1);
                break;
            case R.id.ll_me:
                selectNavigation(2);
                break;
            case R.id.ll_more:
                selectNavigation(3);
                break;
        }
    }

    /***
     * 初始化：创建Fragment，添加到FrameLayout 中（R.id.content)，并且添加到链表fragmetns中
     *
     */
    private void InitFragments() {
        fragments.clear();

        if (fragmentA == null) {
            fragmentA = new FragmentA();
        }
        if (fragmentB == null) {
            fragmentB = new FragmentB();
        }
        if (fragmentC == null) {
            fragmentC = new FragmentC();
        }
        if (fragmentD == null) {
            fragmentD = new FragmentD();
        }
        fragments.add(fragmentA);
        fragments.add(fragmentB);
        fragments.add(fragmentC);
        fragments.add(fragmentD);
//        for (Fragment frag : fragments) {
//            if (!frag.isAdded()) {
//                getSupportFragmentManager().beginTransaction().add(R.id.content, frag).commit();
//            }
//        }
        TabPageAdapter adapter = new TabPageAdapter(getSupportFragmentManager(), fragments);
        viewPager.setAdapter(adapter);
        //滑动响应接口实现
        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                selectNavigation(position);
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
    }

    private void showFragment(int frag) {
        //首先隐藏所有Fragments
        for (Fragment f : fragments) {
            getSupportFragmentManager().beginTransaction().hide(f).commit();
        }
        //获取当前 序号的fragment
        Fragment current_frag = fragments.get(frag);
        if (current_frag != null) {
            getSupportFragmentManager().beginTransaction().show(current_frag).commit();

        }

    }

    class TabPageAdapter extends FragmentPagerAdapter {
        private List<Fragment> fragments;
        public TabPageAdapter(FragmentManager fm,List<Fragment> fragments) {
            super(fm);
            this.fragments=fragments;
        }

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

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

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            super.destroyItem(container, position, object);
        }
    }

    private void selectNavigation(int page) {
        //相关图片，字体变成灰色
        ivHome.setImageResource(R.drawable.bid02);
        ivInvest.setImageResource(R.drawable.bid04);
        ivMe.setImageResource(R.drawable.bid06);
        ivMore.setImageResource(R.drawable.bid08);
        tvHome.setTextColor(getResources().getColor(R.color.home_back_unselected));
        tvInvest.setTextColor(getResources().getColor(R.color.home_back_unselected));
        tvMe.setTextColor(getResources().getColor(R.color.home_back_unselected));
        tvMore.setTextColor(getResources().getColor(R.color.home_back_unselected));


        switch (page) {
            case 0:
                ivHome.setImageResource(R.drawable.bid01);
                tvHome.setTextColor(getResources().getColor(R.color.home_back_selected_green));
                break;
            case 1:
                ivInvest.setImageResource(R.drawable.bid03);
                tvInvest.setTextColor(getResources().getColor(R.color.home_back_selected_green));
                break;
            case 2:
                ivMe.setImageResource(R.drawable.bid05);
                tvMe.setTextColor(getResources().getColor(R.color.home_back_selected_green));
                break;
            case 3:
                ivMore.setImageResource(R.drawable.bid07);
                tvMore.setTextColor(getResources().getColor(R.color.home_back_selected_green));
                break;
        }

        // 选择导航的时候，同时选择Fragment
        //showFragment(page);
        viewPager.setCurrentItem(page,true);
    }


}