Transfer data between Android broadcast receivers and activity

　　Activity transmits data to the broadcast receiver simply by put the data into the intent before sending the broadcast.

How does a broadcast receiver transmit data to the activity? The interface is used here, by defining an interface in the broadcast receiver, and then the activity that receives the broadcast receiver data implements the interface. First look at the chestnut below, the activity sends a broadcast, and then the broadcast receiver returns a string.

Activity layout File

1 <?XML version= "1.0" encoding= "Utf-8"?>2 <LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"3 Xmlns:tools= "Http://schemas.android.com/tools"4 Android:layout_width= "Match_parent"5 Android:layout_height= "Match_parent"6 android:orientation= "vertical"7 Tools:context= "Com.nangch.broadcastreceivertest.MainActivity">8 9     <TextViewTen         Android:id= "@+id/tv" One Android:layout_width= "Wrap_content" A Android:layout_height= "Wrap_content" - Android:text= "Hello" /> -  the     <Button -         Android:id= "@+id/btn" - Android:layout_width= "Match_parent" - Android:layout_height= "Wrap_content" + Android:text= "Send Broadcast"/> - </LinearLayout>

Activity Code

1 Importandroid.content.Intent;2 ImportAndroid.content.IntentFilter;3 ImportAndroid.os.Bundle;4 Importandroid.support.v7.app.AppCompatActivity;5 ImportAndroid.view.View;6 ImportAndroid.widget.Button;7 ImportAndroid.widget.TextView;8 9  Public classMainactivityextendsAppcompatactivityImplementsmyreceiver.message{Ten  One TextView TV; A myreceiver Myreceiver; -  - @Override the     protected voidonCreate (Bundle savedinstancestate) { -         Super. OnCreate (savedinstancestate); - Setcontentview (r.layout.activity_main); -  +         //registering a broadcast receiver -Myreceiver =Newmyreceiver (); +Intentfilter Intentfilter =NewIntentfilter (); AIntentfilter.addaction ("Com.nangch.broadcasereceiver.MYRECEIVER"); at registerreceiver (Myreceiver, intentfilter); -  -         //because the message needs to be injected here, the broadcast sink cannot be statically registered in the Androidmanifest file -Myreceiver.setmessage ( This); -  -TV =(TextView) Findviewbyid (r.id.tv); inButton BTN =(Button) Findviewbyid (R.ID.BTN); -Btn.setonclicklistener (NewView.onclicklistener () { to @Override +              Public voidOnClick (View v) { -Intent Intent =NewIntent ("Com.nangch.broadcasereceiver.MYRECEIVER"); theIntent.putextra ("Hello", Tv.gettext ());//passing data to a broadcast receiver *Sendbroadcast (Intent);//Send broadcast $             }Panax Notoginseng         }); -     } the  + @Override A      Public voidgetmsg (String str) { the         //The data in the Myreceiver can be processed here by implementing the Myreceiver.message interface + tv.append (str); -     } $  $ @Override -     protected voidOnDestroy () { -         Super. OnDestroy (); theUnregisterreceiver (Myreceiver);//unregister a broadcast sink -     }Wuyi}

Broadcast receiver Code

1 ImportAndroid.content.BroadcastReceiver;2 ImportAndroid.content.Context;3 Importandroid.content.Intent;4 ImportAndroid.widget.Toast;5 6  Public classMyreceiverextendsBroadcastreceiver {7     Privatemessage message;8 9 @OverrideTen      Public voidOnReceive (Context context, Intent Intent) { One         //receive the data sent by Mainactivity AToast.maketext (Context, Intent.getstringextra ("Hello"), Toast.length_short). Show (); -  -         //methods for invoking the message interface theMessage.getmsg ("World"); -     } -  -     InterfaceMessage { +          Public voidgetmsg (String str); -     } +  A      Public voidsetmessage (Message message) { at          This. Message =message; -     } -}

As follows:

After clicking the Send Broadcast button:

Defines a message interface in Myreceiver and declares a member variable message of type message. Then let mainactivity implement this interface, and call the Setmessage method to inject mainactivity, so that the mainactivity instance becomes the Myreceiver member variable message, This will handle the data in the Myreceiver. This idea is similar to the idea of setting a button listener when we learn Android, and it's good to think about it.

Demo instance Source download

Transfer data between Android broadcast receivers and activity