Fragment 一

2022-04-30 17:01:00 阅读：262 来源： 互联网

标签：Fragment savedInstanceState Bundle fragment ARG import public

今天学习了Fragment 的创建：静态和动态.代码比较简单，加有注释，不再详解。

Fragment是Android3.0后引入的一个新的API，他出现的初衷是为了适应大屏幕的平板电脑，当然现在他仍然是平板APP UI设计的宠儿，而且我们普通手机开发也会加入这个Fragment，我们可以把他看成一个小型的Activity，又称Activity片段！想想，如果一个很大的界面，我们就一个布局，写起界面来会有多麻烦，而且如果组件多的话是管理起来也很麻烦！而使用Fragment 我们可以把屏幕划分成几块，然后进行分组，进行一个模块化的管理！从而可以更加方便的在运行过程中动态地更新Activity的用户界面！另外Fragment并不能单独使用，他需要嵌套在Activity 中使用，尽管他拥有自己的生命周期，但是还是会受到宿主Activity的生命周期的影响，比如Activity 被destory销毁了，他也会跟着销毁！

首先是文件

MainActivit

package com.example.fragment;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    //静态
    public void staticFragment(View view) {
        Intent intent = new Intent(MainActivity.this, StaticFragmentActivity.class);
        startActivity(intent);
    }
    //动态
    public void DynameicFragment(View view) {
        Intent intent = new Intent(MainActivity.this, DynameicFragmentActivity.class);
        startActivity(intent);
    }
}

StacticFragementActivity

package com.example.fragment;

import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;

public class StaticFragmentActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_staticfragment);
    }
}

package com.example.fragment;

import android.os.Bundle;

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

import com.example.fragment.fragment.DynameicFragment;

public class DynameicFragmentActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dynameicfragment);


        if (savedInstanceState == null) {
            //得到FragmentManager
            FragmentManager fragmentManager = getSupportFragmentManager();
            //得到FragmentTransaction 一次事务打包的操作
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

            fragmentTransaction.add(R.id.dynameicfragment, DynameicFragment.class, null)
                    .setReorderingAllowed(true)
                    //.addToBackStack(null)  //压缩到栈里
                    .commit()
            ;

        }

    }




}

DynameicFragment

package com.example.fragment.fragment;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

import com.example.fragment.R;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link DynameicFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class DynameicFragment extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public DynameicFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment DynameicFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static DynameicFragment newInstance(String param1, String param2) {
        DynameicFragment fragment = new DynameicFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_dynameic, container, false);
    }
}

StaticFragment

package com.example.fragment.fragment;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

import com.example.fragment.R;

/**
 * A simple {@link Fragment} subclass.
 * Use the {@link StaticFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class StaticFragment extends Fragment {

    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;

    public StaticFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment StaticFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static StaticFragment newInstance(String param1, String param2) {
        StaticFragment fragment = new StaticFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_static, container, false);
    }
}

activity_dynameicfragment.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"
    tools:context=".DynameicFragmentActivity">


<androidx.fragment.app.FragmentContainerView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/dynameicfragment"

    >



</androidx.fragment.app.FragmentContainerView>

</LinearLayout>

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"
    tools:context=".MainActivity"
    android:orientation="vertical"
    >

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAlignment="center"
    android:text="静态Fragment"
    android:gravity="center"
    android:onClick="staticFragment"
    android:layout_gravity="center_horizontal"
   android:textAllCaps="false"
   ></Button>


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAlignment="center"
        android:text="动态Fragment"
        android:gravity="center"
        android:layout_gravity="center_horizontal"
        android:textAllCaps="false"
        android:onClick="DynameicFragment"
        ></Button>




</LinearLayout>

activity_staticfragment.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"
    tools:context=".StaticFragmentActivity">

    <fragment
        android:id="@+id/staric"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="com.example.fragment.fragment.StaticFragment"
        tools:layout="@layout/fragment_static"
        ></fragment>

</LinearLayout>

fragment_dynameic.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=".fragment.DynameicFragment">

    <!-- TODO: Update blank fragment layout -->
    <TextView


        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="这是动态fragment" />

</FrameLayout>

fragment_static.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=".fragment.StaticFragment"
    >

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="这是静态fragment"
        android:gravity="center"/>


</FrameLayout>

展示效果

标签：Fragment,savedInstanceState,Bundle,fragment,ARG,import,public
来源： https://www.cnblogs.com/zhaolei0419/p/16210631.html

本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享；
2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关；
3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关；
4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除；
5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。

ICode9

Fragment 一