Android-fragment (iii) communication between different Fragment

In fragment's Java file, you can use Getactivity () to get the activity that invokes it.

And then find another fragment, to communicate

getactivity (). Getfragmentmanager (). Findfragmentbyid (r.id.fragment_list);

However, this coupling is too high to facilitate subsequent modification operations

The communication between the fragment and its attached activity should be done by the activity.

cannot be a direct communication between multiple fragment

The best way to communicate between fragment and its attached activity:

1. Define an interface in the fragment that initiates the event, and declare your method in the interface

2. Require activity to implement this interface in the Onattach method

3. Implement this method in activity

For example, 2 fragment are arranged in an activity, and communication between them depends on activity to complete

Code: Liststoreactivity.java newitemfragment.java Liststorefragment.java

The layout file is: liststore.xml new_item_fragment.xml

Prepare the layout file:

Liststore.xml placed 2 fragment in LinearLayout, pointing to 2 fragment files respectively

    <FragmentAndroid:id= "@+id/fragment_new"Android:name= "Com.rust.liststore.NewItemFragment"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content" />    <FragmentAndroid:id= "@+id/fragment_listview"Android:name= "Com.rust.liststore.ListStoreFragment"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content" />

Place a edittext and a button in the new_item_fragment.xml side

    <EditTextAndroid:id= "@+id/edittx_new"Android:layout_width= "0DP"Android:layout_weight= "4"Android:layout_height= "Wrap_content"Android:hint= "@string/hint_new" />    <ButtonAndroid:id= "@+id/btn_add_new_item"Android:layout_width= "0DP"Android:layout_weight= "1"Android:layout_height= "Wrap_content"Android:text= "@string/hint_add_new_item"        />

Liststorefragment.java

 Public class extends listfragment{///inherit from Listfragment, already packaged listview///do not need to write your own listview }

Newitemfragment.java Main code is as follows

   /*** Declare an interface that defines the method that is passed to the activity * bound activity must implement this method*/     Public InterfaceOnnewitemaddedlistener { Public voidnewitemadded (String content); }    PrivateOnnewitemaddedlistener Onnewitemaddedlistener; PrivateButton Btnadditem; /*Replication Onattach Method*/@Override Public voidOnattach (activity activity) {Super. Onattach (activity); Try{Onnewitemaddedlistener=(Onnewitemaddedlistener) activity; } Catch(classcastexception e) {Throw NewClassCastException (activity.tostring () + "must implement Onnewitemaddedlistener"); }    }        

Liststoreactivity.java

Load main view Setcontentview (R.layout.liststore);

Two fragment to communicate via Liststoreactivity.java

Obtain an instance of Liststorefragment in the OnCreate method, and the Newitemadded method, adding business logic to it

 Public classListstoreactivityextendsActivityImplementsonnewitemaddedlistener{PrivateArraylist<string>data; PrivateArrayadapter<string>adapter; @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.liststore); Data=NewArraylist<string>(); //load the data into the adapteradapter =NewArrayadapter<string> ( This, Android.        R.layout.simple_list_item_1, data); //Listfragment does not need to define a listviewListstorefragment liststorefragment =(liststorefragment) Getfragmentmanager (). Findfragmentbyid (R.id.fragment_listview);    Liststorefragment.setlistadapter (adapter); } @Override Public voidnewitemadded (String content) {//The method in the replication interface, where the business code is implemented        if(!content.equals ("") {data.add (content);        Adapter.notifydatasetchanged (); }    }}

At this point, the communication is completed

Android-fragment (iii) communication between different Fragment