Android是在Android 3.0 (API level 11)开始引入Fragment的。

  可以把Fragment想成Activity中的模块,这个模块有自己的布局,有自己的生命周期,单独处理自己的输入,在Activity运行的时候可以加载或者移除Fragment模块。

  可以把Fragment设计成可以在多个Activity中复用的模块。

  当开发的应用程序同时适用于平板电脑和手机时,可以利用Fragment实现灵活的布局,改善用户体验。


显示类似于tabhost,可以切换界面

private FirstFragment firstFragment;
firstFragment = new FirstFragment();

 

private void setDefaultFragment(){  

        FragmentManager fm = getFragmentManager();  
        FragmentTransaction transaction = fm.beginTransaction();  
        transaction.replace(R.id.content, firstFragment);  
        transaction.show(firstFragment);
        transaction.commit();  
}
Fragment所使用的佈局
    <FrameLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />


//自定义一个FirstFragment继承Fragment

public class FirstFragment extends Fragment implements OnClickListener{

private Button btn;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,                   Bundle savedInstanceState)
{

  View view = inflater.inflate(R.layout.layout_first, container, false);
  btn = (Button) view.findViewById(R.id.button1);
  btn.setOnClickListener(this);
  
  return view;
}

public void onResume(){
  super.onResume();
}

@Override
public void onClick(View arg0) {
  if(arg0.getId() == R.id.button1){
    Toast.makeText(getActivity(), "click", 200).show();
  }
 }
}


//關於Fragment傳值

//可以傳遞數組、對象等

        Bundle bundle = new Bundle();
        bundle.putString("name", "阿三");
        firstFragment.setArguments(bundle);

	FragmentManager fm = getFragmentManager();  
	FragmentTransaction transaction = fm.beginTransaction();  
	transaction.replace(R.id.content, firstFragment);  
	transaction.show(firstFragment);
	transaction.commit();


//接收傳值

  String name = getArguments().getString("name");


如何切換Fragment顯示不同界面

        FragmentManager fm = getFragmentManager();  
        FragmentTransaction transactio
        if(arg1 == true){
            transaction.replace(R.id.content, firstFragment); 
        }else{
            transaction.replace(R.id.content, secondFragment); 
        }
        
        transaction.commit();


Fragment家族常用的API

Fragment常用的三个类:

android.app.Fragment 主要用于定义Fragment

android.app.FragmentManager 主要用于在Activity中操作Fragment

android.app.FragmentTransaction 保证一些列Fragment操作的原子性,熟悉事务这个词,一定能明白~

a、获取FragmentManage的方式:

getFragmentManager() // v4中,getSupportFragmentManager

b、主要的操作都是FragmentTransaction的方法

FragmentTransaction transaction = fm.benginTransatcion();//开启一个事务

transaction.add() 

往Activity中添加一个Fragment

transaction.remove()

从Activity中移除一个Fragment,如果被移除的Fragment没有添加到回退栈,这个Fragment实例将会被销毁。

transaction.replace()

使用另一个Fragment替换当前的,实际上就是remove()然后add()的合体~

transaction.hide()

隐藏当前的Fragment,仅仅是设为不可见,并不会销毁

transaction.show()

显示之前隐藏的Fragment

detach()

会将view从UI中移除,和remove()不同,此时fragment的状态依然由FragmentManager维护。

attach()

重建view视图,附加到UI上并显示。

transatcion.commit()//提交一个事务

注意:常用Fragment的哥们,可能会经常遇到这样Activity状态不一致:State loss这样的错误。主要是因为:commit方法一定要在Activity.onSaveInstance()之前调用。

上述,基本是操作Fragment的所有的方式了,在一个事务开启到提交可以进行多个的添加、移除、替换等操作。

值得注意的是:如果你喜欢使用Fragment,一定要清楚这些方法,哪个会销毁视图,哪个会销毁实例,哪个仅仅只是隐藏,这样才能更好的使用它们。

a、比如:我在FragmentA中的EditText填了一些数据,当切换到FragmentB时,如果希望会到A还能看到数据,则适合你的就是hide和show;也就是说,希望保留用户操作的面板,你可以使用hide和show,当然了不要使劲在那new实例,进行下非null判断。

b、再比如:我不希望保留用户操作,你可以使用remove(),然后add();或者使用replace()这个和remove,add是相同的效果。

c、remove和detach有一点细微的区别,在不考虑回退栈的情况下,remove会销毁整个Fragment实例,而detach则只是销毁其视图结构,实例并不会被销毁。那么二者怎么取舍使用呢?如果你的当前Activity一直存在,那么在不希望保留用户操作的时候,你可以优先使用detach。


部分轉自:http://blog.csdn.net/lmj623565791/article/details/37992017



fragment接收activity的回调处理

// 回调函数

//import android.app.Fragment;

//需要导入.app这个包,V4包测试收不到回调

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    if(data == null){

        return;
    }
}


//*布局文件

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/white"
    android:gravity="center" >
    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
        <View
            android:id="@+id/layout_order_top"
            android:layout_width="match_parent"
            android:layout_height="30dp"
            android:background="@color/main_color"
            android:visibility="gone" />
        <LinearLayout
            android:id="@+id/ll_order_title"
            android:layout_width="match_parent"
            android:layout_height="45dp"
            android:layout_below="@id/layout_order_top"
            android:background="@color/main_color"
            android:visibility="gone" >
            <LinearLayout
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_marginLeft="15dp"
                android:layout_marginRight="5dp"
                android:layout_weight="1"
                android:gravity="center" >
                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:layout_marginBottom="5dp"
                    android:layout_marginTop="5dp"
                    android:background="@drawable/shape_radius_order_search"
                    android:gravity="center"
                    android:orientation="horizontal" >
                    <com.zhiduan.crowdclient.view.ClearEditText
                        android:id="@+id/edt_order_billcode"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_marginLeft="5dp"
                        android:layout_weight="1"
                        android:background="#00000000"
                        android:digits="@string/edit_digits"
                        android:drawableLeft="@drawable/order_magnifier"
                        android:drawableRight="@drawable/homepage_close"
                        android:gravity="center_vertical"
                        android:hint=" 输扫描运单号"
                        android:imeOptions="actionSearch"
                        android:maxLength="20"
                        android:singleLine="true"
                        android:textSize="12sp" />
                    <View
                        android:layout_width="1dp"
                        android:layout_height="match_parent"
                        android:layout_marginBottom="8dp"
                        android:layout_marginLeft="5dp"
                        android:layout_marginRight="5dp"
                        android:layout_marginTop="8dp"
                        android:background="@color/main_bg_color" />
                    <ImageView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_marginLeft="5dp"
                        android:layout_marginRight="12dp"
                        android:onClick="scan"
                        android:src="@drawable/order_scancode" />
                </LinearLayout>
            </LinearLayout>
            <LinearLayout
                android:layout_width="60dp"
                android:layout_height="match_parent"
                android:gravity="center_vertical"
                android:onClick="orderSort"
                android:padding="5dp"
                android:paddingLeft="5dp"
                android:paddingRight="20dp" >
                <ImageView
                    android:id="@+id/imageView_sort"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:src="@drawable/order_screen" />
            </LinearLayout>
        </LinearLayout>
        <LinearLayout
            android:id="@+id/ll_order_menu"
            android:layout_width="fill_parent"
            android:layout_height="50dp"
            android:layout_below="@+id/ll_order_title"
            android:layout_marginTop="3dp"
            android:orientation="vertical" >
            <TabWidget
                android:id="@android:id/tabs"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:visibility="gone" />
            <FrameLayout
                android:id="@+id/fl_bottom_bar"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="#ffffff" >
                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:gravity="center"
                    android:orientation="horizontal" >
                    <LinearLayout
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:orientation="vertical" >
                        <TextView
                            android:id="@+id/tv_order_wait"
                            android:layout_width="match_parent"
                            android:layout_height="0dp"
                            android:layout_weight="1"
                            android:clickable="true"
                            android:gravity="center"
                            android:onClick="waitTaking"
                            android:text="待取件(0)"
                            android:textColor="@color/main_color"
                            android:textSize="16dp" />
                        <View
                            android:id="@+id/view_wait"
                            android:layout_width="match_parent"
                            android:layout_height="1dp"
                            android:background="@color/main_color" />
                    </LinearLayout>
                    <View
                        android:layout_width="0.1dp"
                        android:layout_height="match_parent"
                        android:layout_marginBottom="10dp"
                        android:layout_marginTop="10dp"
                        android:background="@color/gray_4" />
                    <LinearLayout
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:orientation="vertical" >
                        <TextView
                            android:id="@+id/tv_order_sending"
                            android:layout_width="match_parent"
                            android:layout_height="0dp"
                            android:layout_weight="1"
                            android:clickable="true"
                            android:gravity="center"
                            android:onClick="distribution"
                            android:text="配送中(0)"
                            android:textColor="#212124"
                            android:textSize="16dp" />
                        <View
                            android:id="@+id/view_sending"
                            android:layout_width="match_parent"
                            android:layout_height="1dp"
                            android:background="@color/transparent" />
                    </LinearLayout>
                    <View
                        android:layout_width="0.1dp"
                        android:layout_height="match_parent"
                        android:layout_marginBottom="10dp"
                        android:layout_marginTop="10dp"
                        android:background="@color/gray_4" />
                    <LinearLayout
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:orientation="vertical" >
                        <TextView
                            android:id="@+id/tv_order_signed"
                            android:layout_width="match_parent"
                            android:layout_height="0dp"
                            android:layout_weight="1"
                            android:clickable="true"
                            android:gravity="center"
                            android:onClick="signed"
                            android:text="已签收(0)"
                            android:textColor="#212124"
                            android:textSize="16dp" />
                        <View
                            android:id="@+id/view_signed"
                            android:layout_width="match_parent"
                            android:layout_height="1dp"
                            android:background="@color/transparent" />
                    </LinearLayout>
                    <View
                        android:layout_width="0.1dp"
                        android:layout_height="match_parent"
                        android:layout_marginBottom="10dp"
                        android:layout_marginTop="10dp"
                        android:background="@color/gray_4" />
                    <LinearLayout
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_weight="1"
                        android:orientation="vertical" >
                        <TextView
                            android:id="@+id/tv_order_abnormal"
                            android:layout_width="match_parent"
                            android:layout_height="0dp"
                            android:layout_weight="1"
                            android:clickable="true"
                            android:gravity="center"
                            android:onClick="abNormal"
                            android:text="异常件(0)"
                            android:textColor="#212124"
                            android:textSize="16dp" />
                        <View
                            android:id="@+id/view_abnormal"
                            android:layout_width="match_parent"
                            android:layout_height="1dp"
                            android:background="@color/transparent" />
                    </LinearLayout>
                </LinearLayout>
            </FrameLayout>
        </LinearLayout>
        <!-- Tab 内容 -->
        <LinearLayout
            android:id="@+id/ll_order_content"
            android:layout_width="fill_parent"
            android:layout_height="match_parent"
            android:layout_below="@+id/ll_order_menu"
            android:orientation="vertical" >
            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:visibility="gone"
                android:background="#ffffff" />
            <FrameLayout
                android:id="@+id/content"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />
        </LinearLayout>
        <!-- Tab按钮 -->
    </RelativeLayout>
</TabHost>