v7底部欄fragment

detail: v7 實作底部欄

step1: D:\project\push\Infrared\five\v7\kotlin\DemoAnalytic\app\build.gradle

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

dependencies {
    implementation 'com.google.firebase:firebase-core:16.0.9'
    implementation 'com.android.support:design:28.0.0'
}
apply plugin: 'com.google.gms.google-services'      

step2: NavigationActivity 首頁

package com.example.demoanalytic;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;

public class NavigationActivity extends AppCompatActivity {

    private BottomNavigationView bottomNav;
    private FragmentTransaction fragmentTransaction;
    private HomeFragment homeFragment;
    private ResultFragment resultFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);
        initViews();
        initFragments();
    }

    private void initFragments() {
        homeFragment = new HomeFragment();
        setFragment(homeFragment);
    }

    private void setFragment(Fragment fragment) {
        fragmentTransaction = getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.frame_home, fragment).commit();
    }

    private void initViews() {
        bottomNav = (BottomNavigationView) findViewById(R.id.bottomNav);
        bottomNav.setOnNavigationItemSelectedListener(new BottomNavi());
    }


    private class BottomNavi implements BottomNavigationView.OnNavigationItemSelectedListener {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.botnav_home:
                    homeFragment = new HomeFragment();
                    setFragment(homeFragment);
                    return true;
                case R.id.botnav_result:
                    resultFragment = new ResultFragment();
                    setFragment(resultFragment);
                    return true;
                default:
                    return false;
            }
        }
    }
}      

step3: 首頁布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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/nav_drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:weightSum="2"
        android:orientation="vertical">

        <!--background that changes fragments-->
        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:layout_gravity="center_horizontal"
            android:id="@+id/frame_home">
        </FrameLayout>

        <!--bottom nav -->
        <android.support.design.widget.BottomNavigationView
            android:id="@+id/bottomNav"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:layout_weight="1"
            app:elevation="10dp"
            app:menu="@menu/botnav_menu">

        </android.support.design.widget.BottomNavigationView>

    </LinearLayout>

</LinearLayout>      

step4: menu 底部

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/botnav_home"
        android:icon="@drawable/ic_composition"
        android:title="Home"/>

    <item android:id="@+id/botnav_reference"
        android:icon="@drawable/ic_composition"
        android:title="References"/>

    <item android:id="@+id/botnav_result"
        android:icon="@drawable/ic_composition"
        android:title="Results"/>

    <item android:id="@+id/botnav_account"
        android:icon="@drawable/ic_composition"
        android:title="Account"/>

</menu>      

step5: fragment

package com.example.demoanalytic;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class HomeFragment extends  Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment1, null);
    }
}      

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_purple">

</android.support.constraint.ConstraintLayout>