初入Fragment(2)——动态加载fragment

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之前我演示了简单的如何静态加载fragment,但是这种方式在日常的开发中,其实使用的并不是很多,很多情况下,我们都是需要动态的进行fragment的更改,所以这次我就来演示一下简单的动态加载fragment的方法,也就是使用add()、remove()、replace()这三个方法,话不多说,我们来演示一下代码:

首先是在前一章的基础上,新增了一些文件,见我的目录结构:


其中,我在MainActivity的布局文件中,放了两个按钮,实现了跳转,分别进去的是DemoFragmentActivity和ManageFragmentActivity,这里我们主要说明一下ManageFragmentActivity的使用方法。

MainActivity中的java代码:

import android.app.Activity;import android.content.Intent;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);    }    public void fragmentDemo(View view){        startActivity(new Intent(this,DemoFragmentActivity.class));    }    public void fragmentManage(View view){        startActivity(new Intent(this,ManageFragmentActivity.class));    }}

MainActivity的布局文件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:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.czj01.fragmentdemo.MainActivity">    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="fragmentDemo"        android:text="Fragment基本使用方法"/>    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="fragmentManage"        android:text="Fragment基本管理方法"/></LinearLayout>

ManageFragmentActivity的java代码:

import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentTransaction;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;public class ManageFragmentActivity extends AppCompatActivity {    private FragmentManager fragmentManager;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_manage_fragment);    }    public void add(View view){        fragmentManager=getSupportFragmentManager();        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();        FragmentTest fragmentTest = new FragmentTest();        fragmentTransaction.add(R.id.fl_container,fragmentTest,"fragment");        fragmentTransaction.commit();    }    public void remove(View view){        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();        fragmentTransaction.remove(fragmentManager.findFragmentByTag("fragment"));        fragmentTransaction.commit();    }    public void replace(View view){//        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();//        fragmentTransaction.remove(fragmentManager.findFragmentByTag("fragment"));//        fragmentManager = getSupportFragmentManager();//        AnotherFragmentTest anotherFragmentTest = new AnotherFragmentTest();//        fragmentTransaction.add(R.id.fl_container,anotherFragmentTest,"anotherFragment");//        fragmentTransaction.commit();        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();        AnotherFragmentTest anotherFragmentTest = new AnotherFragmentTest();        fragmentTransaction.replace(R.id.fl_container,anotherFragmentTest);        fragmentTransaction.commit();    }    public void onBackPressed(){        finish();    }}

其实,动态加载fragment,主要是需要使用FragmentManage这个类,先创建一个这个累的对象,因为我这里使用的fragment都是supportv4里面的,所以我要使用
getSupportFragmentManager();如何使用的是app下面的,那就直接getFragmentManage()就可以了。
布局文件:
<?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"    android:id="@+id/activity_manage_fragment"    xmlns:tools="http://schemas.android.com/tools"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.czj01.fragmentdemo.ManageFragmentActivity">    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="add"        android:text="add_fragment"/>    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="remove"        android:text="remove_fragment"/>    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="replace"        android:text="replace_fragment"/>    <FrameLayout        android:id="@+id/fl_container"        android:layout_width="wrap_content"        android:layout_height="wrap_content">    </FrameLayout></LinearLayout>

fragment 和anotherfragment 的java代码:

import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;/** * Created by czj01 on 2017/5/8. */public class FragmentTest extends Fragment {    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        return inflater.inflate(R.layout.fragment_list, container, false);    }}

import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;/** * Created by czj01 on 2017/5/9. */public class AnotherFragmentTest extends Fragment {    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        return inflater.inflate(R.layout.another_fragment_list, container, false);    }}
两个布局文件fragment_list和another_fragment_list布局文件:
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:background="#8E8E8E"    android:layout_width="wrap_content"    android:layout_height="wrap_content">    <TextView        android:layout_width="100dp"        android:layout_height="100dp"        android:text="Fragment"/></LinearLayout>


?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:background="#892525"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent">    <TextView        android:layout_width="100dp"        android:layout_height="100dp"        android:text="another_fragment"/></LinearLayout>


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