一、创建Bottom Navigation
使用Android Studio创建工程，在选择activity的时候选择Bottom Navigation Activity
之后 xml文件 代码修改如下
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<FrameLayout
android:id="@+id/content"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="1"
android:layout_marginTop="0dp"
app:layout_constraintBottom_toTopOf="@+id/navigation"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</FrameLayout>
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="0dp"
android:layout_marginStart="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="@menu/navigation" />
</android.support.constraint.ConstraintLayout>
activity代码暂时不变
二、结合Fragment使用
首先我们创建空白的Fragment，如下图。主页要几个页面就创建几个（注意，不能是任意个，主页界面是3-5个）。创建完成之后呢，Fragment类里面的代码很多，我们不需要这些，把他删掉，只剩下这一个方法onCreateView这一个方法就行了。删完后代码如下，所有添加的Fragment类都是这样。
package com.mobileshopdemo.qingyin.myapplicationclassdemo;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* 第一个页面 课表查询
*
* @author qingyin
*
*/
public class BlankFragment extends Fragment {
private View view;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_blank, container, false);
return view;
}
}
创建相对应的布局文件
修改MainActivity代码
package com.mobileshopdemo.qingyin.myapplicationclassdemo;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity {
private FragmentTransaction transaction;
private FragmentManager fragmentManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setDefaultFragment();
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
// 设置默认tab显示页面
private void setDefaultFragment() {
fragmentManager = getSupportFragmentManager();
transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.content, new BlankFragment()).commit();
}
//设置3-5个碎片化界面
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
fragmentManager = getSupportFragmentManager();
transaction = fragmentManager.beginTransaction();
switch (item.getItemId()) {
case R.id.navigation_home:
transaction.replace(R.id.content, new BlankFragment());
transaction.commit();
return true;
case R.id.navigation_dashboard:
transaction.replace(R.id.content, new BlankFragment2());
transaction.commit();
return true;
case R.id.navigation_notifications:
transaction.replace(R.id.content, new BlankFragment3());
transaction.commit();
return true;
}
return false;
}
};
}
在Fragment里面是无法直接findviewbyid找到控件的，必须要在前面加getView().或者view.才行。
注意一点，需要重写onStart方法，所有的控件放到这里面初始化。
@Override
public void onStart() {
TextView textView = getView().findViewById(R.id.textOne);
textView.setText("我是第一个视图哦");
super.onStart();
}
需要添加或更改Bottom图标和文字的需要在Navigation.xml里面修改。
文章参考：https://blog.csdn.net/huakaibuxiangli/article/details/79201944
错误问题参考：踩坑，Fragment使用遇到那些坑 getActivity,Context为空解决办法
