實驗環境：

在Android Studio中進行有關代碼的撰寫和界面效果展示
圖示來源于阿里矢量圖示庫

界面分析：

點擊底端相應區域，中間內容會進行相應切換（將對應的Fragment顯示，其余的Fragment隱藏），下面展示點擊聯系人后，中間內容的變化，

同時點擊選單后，該選單的圖示和文字都將切換為綠色，

界面布局的代碼實作：

1. 頂部top.xml
2. 底端bottom.xml
3. 中間內容四個分段fragment.xml
4. 表單總布局的activity_main.xml
5. 四個分段fragment.xml對應的.java檔案
6. 主函式檔案MainActivity.java

頂部top.xml

（布局可以通過設定android:background屬性改變背景顏色，文本可以通過設定android:textColor屬性改變字體顏色，）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="@color/black">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="50dp"
        android:layout_weight="1"
        android:gravity="center"
        android:text="我的微信"
        android:textColor="@color/white"
        android:textSize="24sp" />

</LinearLayout>

底端bottom.xml

（為節省篇幅此處只給出了第一個垂直式的LinearLayout-聊天選單）
android:gravity屬性可以定義布局內控制元件的對齊方式，居中、水平居中和垂直居中
android:orientation屬性可以定義布局內控制元件的排列方式，一般有水平式和垂直式

<?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"
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:background="@color/colorViewNormal"
    android:gravity="center">

    <LinearLayout
        android:id="@+id/chat"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:gravity="center"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            app:srcCompat="@drawable/chat" />

        <TextView
            android:id="@+id/textView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center"
            android:textColor="@color/black"
            android:text="聊天"
            android:textSize="20sp" />
    </LinearLayout>

</LinearLayout>

中間內容區四個fragment.xml

（同樣只給出了一個分段，其余三個分段類似）

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Fragment_chat">

    <TextView
        android:id="@+id/textView5"
        android:layout_width="wrap_content"
        android:layout_height="50dp"
        android:gravity="center"
        android:text="這是“我的微信”的聊天界面！"
        android:textColor="@color/black"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml

（包含top、middle、bottom三個部分id，用 include 陳述句呼叫頂部和底部導航欄兩個xml檔案）

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <include layout="@layout/top"></include>


    <FrameLayout
        android:id="@+id/frame_content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"></FrameLayout>


    <include layout="@layout/bottom"></include>


</LinearLayout>

fragment_chat.java

(同樣只給出點擊聊天選單后顯示的分段，其余三個類似)

package com.example.mywork;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.fragment.app.Fragment;

public class Fragment_chat extends Fragment {

    public Fragment_chat() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
//        return super.onCreateView(inflater, container, savedInstanceState);
        return inflater.inflate(R.layout.fragment_chat,container,false);
    }
}

MainActivity.java

（各組件的初始化操作及點擊各選單的轉換操作函式）

package com.example.mywork;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    //Fragment
    private Fragment fragment_first=new Fragment_chat();
    private Fragment fragment_second=new Fragment_contacts();
    private Fragment fragment_third=new Fragment_circle_friend();
    private Fragment fragment_fourth=new Fragment_settings();

    //底端選單欄LinearLayout
    private LinearLayout linear_first;
    private LinearLayout linear_second;
    private LinearLayout linear_third;
    private LinearLayout linear_fourth;

    //底端選單欄中的Imageview
    private ImageView imageView_first;
    private ImageView imageView_second;
    private ImageView imageView_third;
    private ImageView imageView_fourth;

    //底端選單欄中的TextView
    private TextView textView_first;
    private TextView textView_second;
    private TextView textView_third;
    private TextView textView_fourth;


    //FragmentManager
    private FragmentManager fragmentManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE );
        setContentView(R.layout.activity_main);

        initView();
        initFragment();
        initEvent();
        selectFragment(0);
        //將第一個圖示設為選中狀態
        imageView_first.setImageResource(R.drawable.chat_green);
        textView_first.setTextColor(getResources().getColor(R.color.colorViewPress));
    }

    @Override
    public void onClick(View view) {
        //每次點擊之后，將所有的ImageView和TextView設定為未選中
        restartButton();

        switch(view.getId())
        {
            case R.id.chat:
                //選擇所點擊的選單對應的圖層片段
                selectFragment(0);
                //將該選單的點擊狀態置為點擊態
                imageView_first.setImageResource(R.drawable.chat_green);
                textView_first.setTextColor(getResources().getColor(R.color.colorViewPress));
                break;
            case R.id.contacts:
                selectFragment(1);
                imageView_second.setImageResource(R.drawable.contacts_green);
                textView_second.setTextColor(getResources().getColor(R.color.colorViewPress));
                break;
            case R.id.circle_friend:
                selectFragment(2);
                imageView_third.setImageResource(R.drawable.circle_people_green);
                textView_third.setTextColor(getResources().getColor(R.color.colorViewPress));
                break;
            case R.id.settings:
                selectFragment(3);
                imageView_fourth.setImageResource(R.drawable.settings_green);
                textView_fourth.setTextColor(getResources().getColor(R.color.colorViewPress));
                break;
            default:
                break;
        }
    }

    //重置選單的點擊狀態，設為未點擊
    private void restartButton() {
        //設定為未點擊狀態
        //第一片段
        imageView_first.setImageResource(R.drawable.chat);
        textView_first.setTextColor(getResources().getColor(R.color.black));
        //第二片段
        imageView_second.setImageResource(R.drawable.contacts);
        textView_second.setTextColor(getResources().getColor(R.color.black));
        //第三片段
        imageView_third.setImageResource(R.drawable.circle_people);
        textView_third.setTextColor(getResources().getColor(R.color.black));
        //第四片段
        imageView_fourth.setImageResource(R.drawable.settings);
        textView_fourth.setTextColor(getResources().getColor(R.color.black));
    }

    //初始化中間的部分的圖層片段
    private void initFragment(){
        fragmentManager=getSupportFragmentManager();
        FragmentTransaction transaction=fragmentManager.beginTransaction();
        transaction.add(R.id.frame_content,fragment_first);
        transaction.add(R.id.frame_content,fragment_second);
        transaction.add(R.id.frame_content,fragment_third);
        transaction.add(R.id.frame_content,fragment_fourth);
        //提交事務
        transaction.commit();
    }

    //初始化各底端的LinearLayout、ImageView和TextView組件
    private  void initView(){
        linear_first=findViewById(R.id.chat);
        linear_second=findViewById(R.id.contacts);
        linear_third=findViewById(R.id.circle_friend);
        linear_fourth=findViewById(R.id.settings);

        imageView_first=findViewById(R.id.imageView1);
        imageView_second=findViewById(R.id.imageView2);
        imageView_third=findViewById(R.id.imageView3);
        imageView_fourth=findViewById(R.id.imageView4);

        textView_first=findViewById(R.id.textView1);
        textView_second=findViewById(R.id.textView2);
        textView_third=findViewById(R.id.textView3);
        textView_fourth=findViewById(R.id.textView4);

    }

    //初始化點擊監聽事件
    private void initEvent(){
        linear_first.setOnClickListener(this);
        linear_second.setOnClickListener(this);
        linear_third.setOnClickListener(this);
        linear_fourth.setOnClickListener(this);
    }

    //隱藏所有圖層分段
    private void hideView(FragmentTransaction transaction){
        transaction.hide(fragment_first);
        transaction.hide(fragment_second);
        transaction.hide(fragment_third);
        transaction.hide(fragment_fourth);
    }

    //選擇相應的圖層分段
    private void selectFragment(int i){
        FragmentTransaction transaction=fragmentManager.beginTransaction();
        //呼叫隱藏所有圖層函式
        hideView(transaction);
        switch (i){
            case 0:
                transaction.show(fragment_first);

                break;
            case 1:
                transaction.show(fragment_second);

                break;
            case 2:
                transaction.show(fragment_third);

                break;
            case 3:
                transaction.show(fragment_fourth);

                break;
            default:
                break;
        }
        //提交轉換事務
        transaction.commit();
    }

}

小結：在Android Studio中進行仿微信APP門戶界面的初步設計，實作了top和bottom導航欄的設計，及中間片段圖層之間的隱藏與切換，最后實作了點擊選單后的顏色切換問題，用到了TextView、ImageView、LinearLayout、Fragment組件，了解了點擊事件onClick函式的撰寫，

具體代碼已上傳至gitee代碼倉庫

——2021.10.04