Fragment之軟件主頁面製做

Fragment是一種Android 3.0後引入的API ,它出現的初衷是爲了適應平板電腦的大屏幕，手機界面小巧可放下的內容有限，而平板寬闊能夠放下手機上的兩三個界面一塊兒合起來展現，多個Fragment能夠組裝拼接嵌套進一個Activity當中，它的生命週期也會受到Activity宿主的生命週期的影響。Fragment有靜態建立和動態建立兩種方式，靜態建立方式是先建立好Fragment，經過繼承Fragment類，實現onCreateView()方法返回一個頁面視圖View，而後在Activity頁面中嵌套進去，經過Activity的佈局文件XML文件中用標籤中的name屬性引入事先建立好的Fragement的java文件。而動態建立方式的不一樣點在於嵌套進Activity這裏，不是經過XML裏面嵌套進去，是在Activity的java文件裏面經過Fragment的事務對象執行增刪改查替換操做嵌套進去。 下面是一個軟件主界面的製做，使用了4個Fragment嵌套進主頁當中展現。 先上效果圖：

第一個Fragment製做文件：HomeActivity.java

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;
import main.com.com.R;

public class HomeActivity  extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.activity_home,null);
        return view;
    }
}

第二個文件：activity_home.xml

<?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="match_parent"
 >
<TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:textAppearance="?android:attr/textAppearanceLarge"
 android:text="第一個頁面"
 android:textSize="40sp"
 android:id="@+id/textView"
android:layout_centerInParent="true" />
</RelativeLayout>

第二個Fragment的製做：SearchActivity.java

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;
import main.com.com.R;
public class SearchActivity extends Fragment{
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 View view=inflater.inflate(R.layout.activity_search,null);
 return view;
}
}

佈局文件activity_search.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:textAppearance="?android:attr/textAppearanceLarge"
 android:text="第二個頁面"
 android:textSize="40sp"
 android:id="@+id/textView2"
 android:layout_centerInParent="true" />
</RelativeLayout>

剩下的2個Fragment的製做同樣的就不重複了。 Activity的文件: MainActivity.java

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import main.com.com.R;
public class MainActivity extends FragmentActivity{
RadioGroup titleGroup;
RadioButton radioHome,radioSearch,radioMore,radioPersonal;
LinearLayout contentLayout;
FragmentManager manager;
FragmentTransaction transaction;
@Override
public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 titleGroup=(RadioGroup)findViewById(R.id.titleGroup);
 radioHome=(RadioButton)findViewById(R.id.radioHome);
 contentLayout=(LinearLayout)findViewById(R.id.contentLayout);
 //1.獲取Fragment管理器對象,這裏用的是support.v4.app包下的Fragment,有個app包下Fragment的不同
 manager=getSupportFragmentManager();
 //2.獲取Fragment事務對象，並開啓事務
 transaction=manager.beginTransaction();
 //3.調用事務的動態方法這裏是給contentLayout控件下添加一個Fragment頁面
 transaction.add(R.id.contentLayout,new HomeActivity());
 //4.把添加事務提交，不提交不生效
 transaction.commit();//提交後事務對象就沒了，須要還要從新得到
 titleGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
     @Override
     public void onCheckedChanged(RadioGroup group, int checkedId) {
         transaction=manager.beginTransaction();
         switch (checkedId){
             case R.id.radioHome:
                 //事務的替換方法，在這個控件下用new HomeActivity()替換舊的Fragment
                 transaction.replace(R.id.contentLayout, new HomeActivity());
                 break;
             case R.id.radioSearch:
                 transaction.replace(R.id.contentLayout,new SearchActivity());
                 break;
             case R.id.radioMore:
                 transaction.replace(R.id.contentLayout, new MoreActivity());
                 break;
             case R.id.radioPersonal:
                 transaction.replace(R.id.contentLayout, new PersonalActivity());
                 break;
         }
         transaction.commit();
     }
 });
}
}

Activity的佈局文件：activity_main.java

<?xml version="1.0" encoding="utf-8"?>
<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:focusable="false"
>
<LinearLayout
 android:id="@+id/contentLayout"
 android:orientation="vertical"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:focusable="false"
 android:background="#ffffff"
 android:gravity="center"
 >
/>
</LinearLayout>
<RadioGroup
android:id="@+id/titleGroup"
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal"
android:layout_alignParentBottom="true"
android:layout_below="@+id/line"
android:focusable="false"
>
 <RadioButton
    android:id="@+id/radioHome"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:gravity="center"
    android:text="@string/title_home"
    android:checked="true"
    android:enabled="true"
    android:focusable="true"
    android:button="@null"
    android:drawableTop="@drawable/home_selected"
    android:drawablePadding="5dp"
    android:padding="5dp"
    />
 <RadioButton
    android:id="@+id/radioSearch"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:layout_gravity="center"
    android:text="@string/title_search"
    android:checked="false"
    android:button="@null"
    android:drawableTop="@drawable/find_selected"
    android:drawablePadding="5dp"
    android:padding="5dp"/>
 <RadioButton
    android:id="@+id/radioMore"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:gravity="center"
    android:text="@string/title_more"
    android:checked="false"
    android:button="@null"
    android:drawableTop="@drawable/more_selected"
    android:drawablePadding="5dp"
    android:padding="5dp"/>
 <RadioButton
    android:id="@+id/radioPersonal"
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:layout_gravity="center"
    android:text="@string/title_personal"
    android:checked="false"
    android:button="@null"
    android:drawableTop="@drawable/personal_user"
    android:drawablePadding="5dp"
    android:padding="5dp"/>
</RadioGroup>
</RelativeLayout>