Android动态添加碎片

我们编写一个能够用过按钮动态更替碎片的app，首先在主页上显示第一个碎片，点击按钮后可以替换到第二个碎片，或者删除已经替换掉的第二个碎片。

一.mainactivity.java

import androidx.fragment.app.fragmentactivity;
import androidx.fragment.app.fragmentmanager;
import androidx.fragment.app.fragmenttransaction;

import android.os.bundle;
import android.util.log;
import android.view.view;
import android.widget.button;

public class mainactivity extends fragmentactivity {

    public mainactivity() {
        log.e("tag", "mainactivity()..");
    }

    @override
    protected void oncreate(bundle savedinstancestate) {
        log.e("tag", "mainactivity oncreate()..");
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.activity_main);//重写oncreate()方法


        // 创建fragment对象
        final myfragment1 fragment1 = new myfragment1();
        // 得到fragmentmanager
        fragmentmanager manager = getsupportfragmentmanager();
        // 得到fragmenttransacation
        fragmenttransaction transaction = manager.begintransaction();
        // 添加fragment对象并提交
        transaction.add(r.id.ll_main, fragment1).commit();

        button button1=(button)findviewbyid(r.id.fragment_1);
        button1.setonclicklistener(new view.onclicklistener() {
            @override
            public void onclick(view view) {
                showfragment2();
            }
        });
        button button2=(button)findviewbyid(r.id.fragment_2);
        button2.setonclicklistener(new view.onclicklistener() {
            @override
            public void onclick(view view) {
                deletefragment2();
            }
        });

    }
    private myfragment2 fragment2;
    public void showfragment2() {
        // 创建fragment对象
        fragment2 = new myfragment2();
        // 得到fragmentmanager
        fragmentmanager manager = getsupportfragmentmanager();
        // 得到fragmenttransacation
        fragmenttransaction transaction = manager.begintransaction();

        //将当前操作添加到回退栈, 这样点击back回到上一个状态
        transaction.addtobackstack(null);

        // 替换fragment对象并提交
        transaction.replace(r.id.ll_main, fragment2).commit();
    }
    public void deletefragment2() {

        // 得到fragmentmanager
        fragmentmanager manager = getsupportfragmentmanager();
        // 得到fragmenttransacation
        fragmenttransaction transaction = manager.begintransaction();
        // 移除fragment对象并提交
        transaction.remove(fragment2).commit();
    }
}

二.activity_main.xml

<?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">
    <linearlayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
<button

    android:id="@+id/fragment_1"
    android:text="切换至第二个碎片"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content" />
    <button
        android:id="@+id/fragment_2"
        android:text="删除第二个碎片"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content" />
    </linearlayout>
<linearlayout
    android:id="@+id/ll_main"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


</linearlayout>
</linearlayout>

编写好的界面如下图所示：

 

 

三.myfragment1.java

import android.os.bundle;

import androidx.fragment.app.fragment;

import android.util.log;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;
import android.widget.textview;


public class myfragment1 extends fragment {



    public myfragment1() {
        // required empty public constructor
    }



    @override
    public void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);

    }

    @override
    public view oncreateview(layoutinflater inflater, viewgroup container,
                             bundle savedinstancestate) {
        // inflate the layout for this fragment
        return inflater.inflate(r.layout.fragment_my_fragment1, container,false);
    }


}

四.myfragment2.java

import android.os.bundle;

import androidx.fragment.app.fragment;

import android.util.log;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;
import android.widget.textview;



public class myfragment2 extends fragment {
    public myfragment2() {
        // required empty public constructor
    }



    @override
    public void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);

    }

    @override
    public view oncreateview(layoutinflater inflater, viewgroup container,
                             bundle savedinstancestate) {
        // inflate the layout for this fragment
        return inflater.inflate(r.layout.fragment_my_fragment2, container,false);
    }

}

五.fragment1.xml

<?xml version="1.0" encoding="utf-8"?>
<framelayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".myfragment1">

    <!-- todo: update blank fragment layout -->
    <textview
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="这是第一个碎片" />

</framelayout>

六.fragment2.xml

<?xml version="1.0" encoding="utf-8"?>
<framelayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".myfragment2">

    <!-- todo: update blank fragment layout -->
    <textview
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="这是第二个碎片" />

</framelayout>

完毕