BottomNavigationView的基本使用

红太狼 2023-07-20 05:54 11阅读 0赞

因为最近自己在写一个壁纸类的apk，需要底部的导航栏来配合fragment来使用，所以写个笔记供读者阅览。

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## 1.简介 ##

BottomNavigationView是一个底部导航栏控件，一般和fragment一起使用。

## 2.导包 ##

implementation 'com.google.android.material:material:1.0.0'

## 3.使用 ##

<android.support.design.widget.BottomNavigationView
            android:id="@+id/bottomNavigation"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:itemTextColor="@drawable/main_bottom_navigation"
            app:itemIconTint="@drawable/main_bottom_navigation"
            app:menu="@menu/navigation">
        </android.support.design.widget.BottomNavigationView>

控件分析：  
**app:itemTextColor 指的是导航栏文字的颜色  
app:itemIconTint 指的是导航栏中图片的颜色  
app:iteamBackground 指的是底部导航栏的背景颜色,默认是主题的颜色  
app:menu 指的是布局（文字和图片都写在这个里面）**

注意:关于app：的使用，都需要在最外层里面加入下面这个  
xmlns:app="[http://schemas.android.com/apk/res-auto][http_schemas.android.com_apk_res-auto]" 系统会默认导入的，如果没有就手动导入。

## 4.navigation界面 ##

<?xml version="1.0" encoding="utf-8"?>
    <menu xmlns:android="http://schemas.android.com/apk/res/android">
        <item
            android:id="@+id/main_wallpaper"
            android:icon="@drawable/ic_wallpaper"
            android:title="@string/main_wallpaper" />
        <item
            android:id="@+id/main_music"
            android:icon="@drawable/ic_music"
            android:title="@string/main_music" />
        <item
            android:id="@+id/main_my"
            android:icon="@drawable/ic_user"
            android:title="@string/main_user" />
    </menu>

ic\_开头的是图片  
main\_开头的是文字

**可以从icon和title来看出来，这里我建议大家使用文字的时候尽量不要写在xml里面，而是写在strings里面，因为我经常做多国语言的翻译，有这个习惯。这个习惯会让你以后对文字的优化，或者添加都有好的提升。**

下面我们看控件点击时候的颜色

## 5.main\_bottom\_navigation的界面 ##

<?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
        <item android:color="#0015ff" android:state_checked="true"></item>
        <item android:color="#0084ff" android:state_checked="false"></item>
    </selector>

item里面有很多的属性，例如focus，drawable。

## 6.完整的activity代码 ##

import android.os.Build;
    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.os.Bundle;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.WindowManager;
    import android.widget.FrameLayout;
    
    import bottomnavigationview.luo.com.bottomnavigationview02.fragment.MusicFragment;
    import bottomnavigationview.luo.com.bottomnavigationview02.fragment.MyFragment;
    import bottomnavigationview.luo.com.bottomnavigationview02.fragment.WallpaperFragment;
    
    /**
     * Created by luo on 2019/7/3.
     */
    
    public class MainActivity extends AppCompatActivity {
    
        private FrameLayout mainFrame;
        private BottomNavigationView bottomNavigation;
        private WallpaperFragment wallpaperFragment;
        private MusicFragment musicFragment;
        private MyFragment myFragment;
        private Fragment[] fragments;
        private int lastfragment = 0;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            setHalfTransparent();
            initView();
        }
    
        private void initView() {
            wallpaperFragment = new WallpaperFragment();
            musicFragment = new MusicFragment();
            myFragment = new MyFragment();
            fragments = new Fragment[]{wallpaperFragment, musicFragment, myFragment};
            mainFrame = (FrameLayout) findViewById(R.id.mainFrame);
            //设置fragment到布局
            getSupportFragmentManager().beginTransaction().replace(R.id.mainFrame, wallpaperFragment).show(wallpaperFragment).commit();
    
            bottomNavigation = (BottomNavigationView) findViewById(R.id.bottomNavigation);
    
            //这里是bottomnavigationview的点击事件  
            bottomNavigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
    
        }
    
        private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
                = new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                switch (item.getItemId()) {
                    case R.id.main_wallpaper:
                      //这里因为需要对3个fragment进行切换
                      //start 
                        if (lastfragment != 0) {
                            switchFragment(lastfragment, 0);
                            lastfragment = 0;
                        }
                      //end    
                      //如果只是想测试按钮点击，不管fragment的切换，可以把start到end里面的内容去掉
                        return true;
                    case R.id.main_music:
                        if (lastfragment != 1) {
                            switchFragment(lastfragment, 1);
                            lastfragment = 1;
                        }
                        return true;
                    case R.id.main_my:
                        if (lastfragment != 2) {
                            switchFragment(lastfragment, 2);
                            lastfragment = 2;
                        }
                        return true;
                    default:
                        break;
                }
                return false;
            }
        };
    
        /**
        *切换fragment
        */
        private void switchFragment(int lastfragment, int index) {
            FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
            //隐藏上个Fragment
            transaction.hide(fragments[lastfragment]);
            if (fragments[index].isAdded() == false) {
                transaction.add(R.id.mainFrame, fragments[index]);
            }
            transaction.show(fragments[index]).commitAllowingStateLoss();
        }
    
        /**
         * 半透明状态栏
         */
        protected void setHalfTransparent() {
            if (Build.VERSION.SDK_INT >= 21) {//21表示5.0
                View decorView = getWindow().getDecorView();
                int option = View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_STABLE;
                decorView.setSystemUiVisibility(option);
                getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            } else if (Build.VERSION.SDK_INT >= 19) {//19表示4.4
                getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
                //虚拟键盘也透明
                // getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
            }
        }
    }

## 7.小结 ##

1.BottomNavigationView需要导包，与appcompat一致  
2.需要一个menu的xml，文字和图片  
3.按钮的点击设置

## 8.android studio自动创建BottomNavigationView ##

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[Image 1]: 
[http_schemas.android.com_apk_res-auto]: https://links.jianshu.com/go?to=http%3A%2F%2Fschemas.android.com%2Fapk%2Fres-auto