Android fragment入门一

fragment简单来说，想当于一个轻量级的activity，它不需要到清单文件中配置。用法也比较简单，fragment是3.0以后才引入的新API，下面的例子要3.0以上才行。

效果图

package com.example.fragment;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {

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

package com.example.fragment;

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

public class Fragment1 extends Fragment{

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment1, null);
}
}

package com.example.fragment;

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

public class Fragment2 extends Fragment{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//填充器，将fragment的xml文件，实例化成对象
return inflater.inflate(R.layout.fragment2, null);
}
}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<fragment
android:id="@+id/fragment1"
android:name="com.example.fragment.Fragment1"
android:layout_width="0dip"
android:layout_height="fill_parent"
android:layout_weight="1" />
<fragment
android:id="@+id/fragment2"
android:name="com.example.fragment.Fragment2"
android:layout_width="0dip"
android:layout_height="fill_parent"
android:layout_weight="1" />
</LinearLayout>

fragment1.xml

<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"
android:background="#ff0000" >

<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="fragment1" />

</RelativeLayout>

fragment2.xml

<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"
android:background="#ffff00" >

<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="fragment2" />

</RelativeLayout>

横竖屏效果图，只需要改变上面代码中mainActivity一点代码：





package com.example.fragment;

import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//得到手机屏幕宽高
int with = getWindowManager().getDefaultDisplay().getWidth();
int height = getWindowManager().getDefaultDisplay().getHeight();
Fragment1 fragment1 = new Fragment1();
Fragment2 fragment2 = new Fragment2();
FragmentManager fm = getFragmentManager();
//事务，为了保证在修改界面保证一致性，所以加上事务
FragmentTransaction ft = fm.beginTransaction();
if(with > height){//横屏的时候 ctrl + f11/12 横竖屏切换
ft.replace(android.R.id.content, fragment1);
}else{
ft.replace(android.R.id.content, fragment2);
}
ft.commit();
}
}