25.fragment动态添加与管理

一、压缩包

fragmentManagers.zip

二、实现步骤

1.添加两个按钮和切换的页面放的容器framelayout

2.添加fragment，进行切换的片段

3.删除fragment自带且不需要的内容

4.动态切换fragment

三、整体代码

1.布局activity_main.xml文件

<?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">
    <Button
        android:id="@+id/btn_one"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/change"></Button>
    <Button
        android:id="@+id/btn_two"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/replace"></Button>
    <FrameLayout
        android:id="@+id/fl_item"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorPrimary"></FrameLayout>
</LinearLayout>

2.布局fragment_blank_fragment1.xml文件

<?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=".fragment.BlankFragment1">
    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment" />
</FrameLayout>

3.布局fragment_blank_fragment2.xml文件

<?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=".fragment.BlankFragment2">
    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/这是第二个页面" />
</FrameLayout>

4.MainActivity文件代码

package com.example.fragmentmanagers;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import com.example.fragmentmanagers.fragment.BlankFragment1;
import com.example.fragmentmanagers.fragment.BlankFragment2;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn_one = findViewById(R.id.btn_one);
        btn_one.setOnClickListener(this);
        Button btn_two = findViewById(R.id.btn_two);
        btn_two.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_one:
                replaceFragment(new BlankFragment1());
                break;
            case R.id.btn_two:
                replaceFragment(new BlankFragment2());
        }
    }
    //动态切换fragment
    private void replaceFragment(Fragment fragment) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.fl_item,fragment);
        transaction.commit();
    }
}

5.BlankFragment1文件代码

package com.example.fragmentmanagers.fragment;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.fragmentmanagers.R;
public class BlankFragment1 extends Fragment {
    @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_blank_fragment1, container, false);
    }
}

6.BlankFragment2文件代码

package com.example.fragmentmanagers.fragment;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.fragmentmanagers.R;
public class BlankFragment2 extends Fragment {
    @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_blank_fragment2, container, false);
    }
}

7.效果图：

 （1）点击change<br />![image.png](https://cdn.nlark.com/yuque/0/2021/png/1574587/1623400078629-daf18b88-eedd-4e25-a034-4c85ef7ae204.png#clientId=u6aa22632-3a92-4&from=paste&height=588&id=u75f8602f&margin=%5Bobject%20Object%5D&name=image.png&originHeight=588&originWidth=838&originalType=binary&ratio=1&size=87613&status=done&style=none&taskId=u8b814ee1-384f-4290-bac8-bbc1921ddc9&width=838)<br />     （2）点击replace<br />![image.png](https://cdn.nlark.com/yuque/0/2021/png/1574587/1623400127692-76b174b2-440a-49f8-8551-a7b3fede6d58.png#clientId=u6aa22632-3a92-4&from=paste&height=615&id=ucc38b0ea&margin=%5Bobject%20Object%5D&name=image.png&originHeight=615&originWidth=837&originalType=binary&ratio=1&size=94794&status=done&style=none&taskId=uccce711e-da31-4daf-ad33-d479aa3efba&width=837)

四、片段切换的总结

1.创建一个待处理的fragment

2.获取FragmentManeger，一般都是通过getSupportFragmentManager()

3.开启一个事务transaction，一般调用fragmentManager的beginTransaction()

4.使用transaction进行fragment的替换

5.提交事务