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Fragment教程之Fragment基本使用

2019-08-14  本文已影响0人  手指乐

静态使用Fragment

主要有以下两个步骤:
1、继承Fragment,重写onCreateView决定Fragment的布局
2、在Activity中声明此Fragment,就当和普通的View一样

下面展示一个例子(我使用2个Fragment作为Activity的布局,一个Fragment用于标题布局,一个Fragment用于内容布局)

TitleFragment的布局文件:

<?xml version="1.0" encoding="utf-8"?>  
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:layout_width="match_parent"  
    android:layout_height="45dp"  
    android:background="@drawable/title_bar" >  
  
    <ImageButton  
        android:id="@+id/id_title_left_btn"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_centerVertical="true"  
        android:layout_marginLeft="3dp"  
        android:background="@drawable/showleft_selector" />  
  
    <TextView  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        android:gravity="center"  
        android:text="我不是微信"  
        android:textColor="#fff"  
        android:textSize="20sp"  
        android:textStyle="bold" />  
  
</RelativeLayout>  

TitleFragment:

package com.zhy.zhy_fragments;  
  
import android.app.Fragment;  
import android.os.Bundle;  
import android.view.LayoutInflater;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.view.ViewGroup;  
import android.widget.ImageButton;  
import android.widget.Toast;  
  
public class TitleFragment extends Fragment  
{  
  
    private ImageButton mLeftMenu;  
  
    @Override  
    public View onCreateView(LayoutInflater inflater, ViewGroup container,  
            Bundle savedInstanceState)  
    {  
        View view = inflater.inflate(R.layout.fragment_title, container, false);  
        mLeftMenu = (ImageButton) view.findViewById(R.id.id_title_left_btn);  
        mLeftMenu.setOnClickListener(new OnClickListener()  
        {  
            @Override  
            public void onClick(View v)  
            {  
                Toast.makeText(getActivity(),  
                        "i am an ImageButton in TitleFragment ! ",  
                        Toast.LENGTH_SHORT).show();  
            }  
        });  
        return view;  
    }  
}  

ContentFragment布局:

<?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:orientation="vertical" >  
  
    <TextView  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        android:gravity="center"  
        android:text="使用Fragment做主面板"  
        android:textSize="20sp"  
        android:textStyle="bold" />  
  
</LinearLayout>  

ContentFragment:

package com.zhy.zhy_fragments;  
  
import android.app.Fragment;  
import android.os.Bundle;  
import android.view.LayoutInflater;  
import android.view.View;  
import android.view.ViewGroup;  
  
public class ContentFragment extends Fragment  
{  
  
    @Override  
    public View onCreateView(LayoutInflater inflater, ViewGroup container,  
            Bundle savedInstanceState)  
    {  
        return inflater.inflate(R.layout.fragment_content, container, false);  
    }  
  
}  

MainActivity:

package com.zhy.zhy_fragments;  
  
import android.app.Activity;  
import android.os.Bundle;  
import android.view.Window;  
  
public class MainActivity extends Activity  
{  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState)  
    {  
        super.onCreate(savedInstanceState);  
        requestWindowFeature(Window.FEATURE_NO_TITLE);  
        setContentView(R.layout.activity_main);  
    }  
  
}  

MainActivity布局文件:

<RelativeLayout 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" >  
  
    <fragment  
        android:id="@+id/id_fragment_title"  
        android:name="com.zhy.zhy_fragments.TitleFragment"  
        android:layout_width="fill_parent"  
        android:layout_height="45dp" />  
  
    <fragment  
        android:layout_below="@id/id_fragment_title"  
        android:id="@+id/id_fragment_content"  
        android:name="com.zhy.zhy_fragments.ContentFragment"  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent" />  
  
</RelativeLayout>  

注意:fragment首字母小写,一定要给id
是不是把Fragment当成普通的View一样声明在Activity的布局文件中,然后所有控件的事件处理等代码都由各自的Fragment去处理,瞬间觉得Activity好干净有木有~~代码的可读性、复用性以及可维护性是不是瞬间提升了

动态的使用Fragment

我们实现以下效果:

image
activity布局代码:
<RelativeLayout 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" >  
  
    <fragment  
        android:id="@+id/id_fragment_title"  
        android:name="com.zhy.zhy_fragments.TitleFragment"  
        android:layout_width="fill_parent"  
        android:layout_height="45dp" />  
  
    <include  
        android:id="@+id/id_ly_bottombar"  
        android:layout_width="fill_parent"  
        android:layout_height="55dp"  
        android:layout_alignParentBottom="true"  
        layout="@layout/bottombar" />  
  
    <FrameLayout  
        android:id="@+id/id_content"  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        android:layout_above="@id/id_ly_bottombar"  
        android:layout_below="@id/id_fragment_title" />  
  
</RelativeLayout>  

activity代码:

package com.zhy.zhy_fragments;  
  
import android.app.Activity;  
import android.app.FragmentManager;  
import android.app.FragmentTransaction;  
import android.os.Bundle;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.view.Window;  
import android.widget.LinearLayout;  
  
public class MainActivity extends Activity implements OnClickListener  
{  
    private LinearLayout mTabWeixin;  
    private LinearLayout mTabFriend;  
  
    private ContentFragment mWeixin;  
    private FriendFragment mFriend;  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState)  
    {  
        super.onCreate(savedInstanceState);  
        requestWindowFeature(Window.FEATURE_NO_TITLE);  
        setContentView(R.layout.activity_main);  
  
        // 初始化控件和声明事件  
        mTabWeixin = (LinearLayout) findViewById(R.id.tab_bottom_weixin);  
        mTabFriend = (LinearLayout) findViewById(R.id.tab_bottom_friend);  
        mTabWeixin.setOnClickListener(this);  
        mTabFriend.setOnClickListener(this);  
  
        // 设置默认的Fragment  
        setDefaultFragment();  
    }  
  
    private void setDefaultFragment()  
    {  
        FragmentManager fm = getFragmentManager();  
        FragmentTransaction transaction = fm.beginTransaction();  
        mWeixin = new ContentFragment();  
        transaction.replace(R.id.id_content, mWeixin);  
        transaction.commit();  
    }  
  
    @Override  
    public void onClick(View v)  
    {  
        FragmentManager fm = getFragmentManager();  
        // 开启Fragment事务  
        FragmentTransaction transaction = fm.beginTransaction();  
  
        switch (v.getId())  
        {  
        case R.id.tab_bottom_weixin:  
            if (mWeixin == null)  
            {  
                mWeixin = new ContentFragment();  
            }  
            // 使用当前Fragment的布局替代id_content的控件  
            transaction.replace(R.id.id_content, mWeixin);  
            break;  
        case R.id.tab_bottom_friend:  
            if (mFriend == null)  
            {  
                mFriend = new FriendFragment();  
            }  
            transaction.replace(R.id.id_content, mFriend);  
            break;  
        }  
        // transaction.addToBackStack();  
        // 事务提交  
        transaction.commit();  
    }  
  
} 

Fragment代码跟上面静态使用类似

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