BottomNavigationView的使用与碰到的坑

花了两个小时，晕乎乎的，终于搞完了，废话不多说，直接上代码。。。

坑点：BottomNavigationView在使用此控件时需要依赖25.3.1-27.1.0之间的版本，当然，目前最高版本支支持到27.1.0

　　implementation 'com.android.support:design:27.1.0'

具体使用：网上有各种写法均可使用，我这里就不多说了简单吧代码给贴上，当然一些资源图片我就不给了

layout布局文件下activity_home.xml

<?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"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

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

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        app:itemIconTint="@drawable/bottom_navigation_selector"
        app:itemTextColor="@drawable/bottom_navigation_selector"
        app:menu="@menu/menu_bottom_navigation" />

    <View
        android:layout_width="match_parent"
        android:layout_height="5dp"
        android:layout_above="@id/bottom_navigation"
        android:background="@drawable/bottom_shadow" />

</RelativeLayout>

fragment_base.xml

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

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"/>

</RelativeLayout>

values文件下values.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <dimen name="design_bottom_navigation_active_text_size">14dp</dimen>
    <dimen name="design_bottom_navigation_text_size">14dp</dimen>
</resources>
drawable文件下
bottom_navigation_selector.xml

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

bottom_shadow.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="90"
        android:endColor="#0000"
        android:startColor="#30000000"
        android:type="linear"/>

</shape>


menu文件夹下
menu_bottom_navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/item_news"
        android:icon="@mipmap/ic_news_gray"
        android:title="新闻" />
    <item
        android:id="@+id/item_lib"
        android:icon="@mipmap/ic_library_gray"
        android:title="图书" />

    <item
        android:id="@+id/item_find"
        android:icon="@mipmap/ic_discovery_gray"
        android:title="发现" />

</menu>

资源文件基本就这些，还有一些图片和色值就不贴了
Java代码：

HomeActivity.java

package com.jlj.bottomnavigationdemo;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;

/**
* Created by jlj on 2019/2/13.
* HomeActivity 主界面
*/

public class HomeActivity extends AppCompatActivity {

private ViewPager viewPager;
private MenuItem menuItem;
private BottomNavigationView bottomNavigationView;

@SuppressLint("ClickableViewAccessibility")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);

viewPager = (ViewPager) findViewById(R.id.viewpager);
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation);
//默认 >3 的选中效果会影响ViewPager的滑动切换时的效果，故利用反射去掉
BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
bottomNavigationView.setOnNavigationItemSelectedListener(
new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.item_news:
viewPager.setCurrentItem(0);
break;
case R.id.item_lib:
viewPager.setCurrentItem(1);
break;
case R.id.item_find:
viewPager.setCurrentItem(2);
break;
}
return false;
}
});

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}

@Override
public void onPageSelected(int position) {
if (menuItem != null) {
menuItem.setChecked(false);
} else {
bottomNavigationView.getMenu().getItem(0).setChecked(false);
}
menuItem = bottomNavigationView.getMenu().getItem(position);
menuItem.setChecked(true);
}

@Override
public void onPageScrollStateChanged(int state) {
}
});

// 禁止ViewPager滑动
viewPager.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return true;
}
});

setupViewPager(viewPager);
}

private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());

adapter.addFragment(BaseFragment.newInstance("新闻"));
adapter.addFragment(BaseFragment.newInstance("图书"));
adapter.addFragment(BaseFragment.newInstance("发现"));
viewPager.setAdapter(adapter);
}
}　　

ViewPagerAdapter.java

package com.fedming.bottomnavigationdemo;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

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

/**
 * Created by jlj on 2019/2/13.
 * ViewPagerAdapter
 */

public class ViewPagerAdapter extends FragmentPagerAdapter {

    private final List<Fragment> mFragmentList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

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

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

    public void addFragment(Fragment fragment) {
        mFragmentList.add(fragment);
    }

}

BottomNavigationViewHelper.java

package com.fedming.bottomnavigationdemo;

import android.support.design.internal.BottomNavigationItemView;
import android.support.design.internal.BottomNavigationMenuView;
import android.support.design.widget.BottomNavigationView;

import java.lang.reflect.Field;

// 利用反射，改变 item 中 mShiftingMode 的值
public class BottomNavigationViewHelper {

    public static void disableShiftMode(BottomNavigationView navigationView) {

        BottomNavigationMenuView menuView = (BottomNavigationMenuView) navigationView.getChildAt(0);
        try {
            Field shiftingMode = menuView.getClass().getDeclaredField("mShiftingMode");
            shiftingMode.setAccessible(true);
            shiftingMode.setBoolean(menuView, false);
            shiftingMode.setAccessible(false);

            for (int i = 0; i < menuView.getChildCount(); i++) {
                BottomNavigationItemView itemView = (BottomNavigationItemView) menuView.getChildAt(i);
                itemView.setShiftingMode(false);
                itemView.setChecked(itemView.getItemData().isChecked());
            }

        } catch (NoSuchFieldException | IllegalAccessException e) {
            e.printStackTrace();
        }
    }
}

BaseFragment.java

package com.fedming.bottomnavigationdemo;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

/**
 * Created by jlj on 2019/2/13.
 * BaseFragment
 */

public class BaseFragment extends Fragment {
    public static BaseFragment newInstance(String info) {
        Bundle args = new Bundle();
        BaseFragment fragment = new BaseFragment();
        args.putString("info", info);
        fragment.setArguments(args);
        return fragment;
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_base, null);
        TextView tvInfo = (TextView) view.findViewById(R.id.textView);
        tvInfo.setText(getArguments().getString("info"));
        tvInfo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Snackbar.make(v, "Don't click me.please!.", Snackbar.LENGTH_SHORT).show();
            }
        });
        return view;
    }
}
去除动画效果，水波纹效果，建议参考：https://www.jianshu.com/p/dd31d7f07b2d
好，到这里代码已经完成，如果有问题请留言