Fragment的动态添加-kotlin

Fragment是一种可以嵌入到Activity当中的UI片段
可以使用他来为app适配大屏平板
参考资料：《第一行代码》
喜欢就坚持吧！

效果

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与之前写的界面的区别,就是这个是由一左一右两个Fragment构成的,能更好的的适配平板设备.

具体实现

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左Fragment布局left_layout.xml

<?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="match_parent">
    <Button
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/go"/>
</LinearLayout>

右Fragment布局(切换前)right_layout.xml

<?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="match_parent"
    android:background="#126BE6">
</LinearLayout>

右Fragment布局(切换后)another_right_layout.xml

<?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="match_parent"
    android:background="#E61912">
</LinearLayout>

主布局activity_main.xml

<?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=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal">
        <fragment
            android:id="@+id/leftFragment"
            android:name="com.example.fragmenttest2.LeftFragment"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="match_parent"/>
        <FrameLayout
            android:id="@+id/rightLayout"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="match_parent" />
    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

逻辑实现MainActivity.kt

package com.example.fragmenttest2

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import kotlinx.android.synthetic.main.left_fragment.*

//载入左布局文件
class LeftFragment():Fragment(){
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return inflater.inflate(R.layout.left_fragment,container,false)
    }
}
//载入右布局文件(切换前)
class RightFragment():Fragment(){
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return inflater.inflate(R.layout.right_fragment,container,false)
    }
}
//载入右布局文件(切换后)
class AnotherRightFragment():Fragment(){
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return inflater.inflate(R.layout.another_right_fragment,container,false)
    }
}
class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        replaceFragment(RightFragment())    //默认情况下加载切换前的右布局文件
        button.setOnClickListener{
            replaceFragment(AnotherRightFragment()) //点击后动态切换为左布局文件
        }
    }
    private fun replaceFragment(fragment: Fragment){
        val fragmentManager = supportFragmentManager //获取FragmentManager
        val transaction = fragmentManager.beginTransaction() //开启一个事务
        transaction.replace(R.id.rightLayout,fragment)  //替换容器内的fragment
        transaction.addToBackStack(null)    //返回栈,实现按下back键返回上一个fragment
        transaction.commit()    //提交事务
    }
}