一、建立Bottom Navigation

使用Android Studio建立工程，在選擇activity的時候選擇Bottom Navigation Activity

之後 xml檔案 程式碼修改如下

<?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程式碼暫時不變

二、結合Fragment使用

首先我們建立空白的Fragment，如下圖。主頁要幾個頁面就建立幾個（注意，不能是任意個，主頁介面是3-5個）。建立完成之後呢，Fragment類裡面的程式碼很多，我們不需要這些，把他刪掉，只剩下這一個方法onCreateView這一個方法就行了。刪完後代碼如下，所有新增的Fragment類都是這樣。

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;

/**
 * 第一個頁面 課表查詢
 *
 * @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;
    }
}

 

建立相對應的佈局檔案

修改MainActivity程式碼

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);
    }

    // 設定預設tab顯示頁面
    private void setDefaultFragment() {
        fragmentManager = getSupportFragmentManager();
        transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.content, new BlankFragment()).commit();

    }

    //設定3-5個碎片化介面
    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裡面是無法直接findviewbyid找到控制元件的，必須要在前面加getView().或者view.才行。

注意一點，需要重寫onStart方法，所有的控制元件放到這裡面初始化。

@Override
    public void onStart() {
        TextView textView = getView().findViewById(R.id.textOne);
        textView.setText("我是第一個檢視哦");
        super.onStart();
    }

需要新增或更改Bottom圖示和文字的需要在Navigation.xml裡面修改。