Android实验：广播实验

广播

Android 应用与 Android 系统和其他 Android 应用之间可以相互收发广播消息，这与发布-订阅设计模式相似。这些广播会在所关注的事件发生时发送。举例来说，Android 系统会在发生各种系统事件时发送广播，例如系统启动或设备开始充电时。再比如，应用可以发送自定义广播来通知其他应用它们可能感兴趣的事件（例如，一些新数据已下载）。

应用可以注册接收特定的广播。广播发出后，系统会自动将广播传送给同意接收这种广播的应用。

一般来说，广播可作为跨应用和普通用户流之外的消息传递系统。但是，您必须小心，不要滥用在后台响应广播和运行作业的机会，因为这会导致系统变慢

关于详细的广播介绍什么的就不在这里叙述了，贴一个笔者认为写的详尽且通俗的文章
linkhttp://t.csdnimg.cn/wRnOF感兴趣可以自行了解

实验目的

1、了解使用Intent进行组件通信的原理；
2、了解Intent过滤器的原理和匹配机制；
3、掌握发送和接收广播的方法

实验内容

任务1、普通广播；
任务2、系统广播；
任务3、有序广播；

实验要求

1、练习使用静态方法和动态方法注册广播接收器
2、练习发送广播消息的方法；

项目结构

在这里插入图片描述

代码实现

ActionReceiver.java

import android.app.Activity;
//import android.content.ComponentName;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;import androidx.annotation.Nullable;import com.example.exp5.R;public class ActionReceiver extends Activity {protected static final String ACTION ="com.eoeAndroid.broadcastReceiver.RECEIVER_ACTION";private MyReceiver myReceiver;@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.actionlayout);}public void sendAct(View view){Intent intent=new Intent();       //实例化Intentintent.setAction(ACTION);      //设置Intent的action属性intent.putExtra("info","动态方法");sendBroadcast(intent);}public void register(View view){myReceiver = new MyReceiver();IntentFilter filter = new IntentFilter();filter.addAction(ACTION);registerReceiver(myReceiver, filter);}public void unregister(View view){unregisterReceiver(myReceiver);}
}

mainActivity.java

import androidx.appcompat.app.AppCompatActivity;import android.content.ComponentName;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;import com.example.exp5.R;public class mainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}public void staticSys(View view){Intent intent = new Intent(mainActivity.this, StaticReceiver.class);startActivity(intent);}public void actionSys(View view){Intent intent = new Intent(mainActivity.this, ActionReceiver.class);startActivity(intent);}

MyOrderReceiverOne.java

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;public class MyOrderReceiverOne extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {System.out.println("我收到有序的啦");}
}

MyOrderReceiverTwo.java

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;public class MyOrderReceiverTwo extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {System.out.println("我收到有序的啦");}
}

MyOrderReceiverThree.java

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;public class MyOrderReceiverThree extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {System.out.println("我收到有序的啦");}
}

MyReceiver.java

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.view.Gravity;
import android.widget.Toast;public class MyReceiver extends BroadcastReceiver {public MyReceiver() {}@Overridepublic void onReceive(Context context, Intent intent) {Toast t = Toast.makeText(context,"广播方式："+intent.getStringExtra("info"), Toast.LENGTH_SHORT);t.setGravity(Gravity.TOP,0,40);t.show();}
}

StaticReceiver.java

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;import com.example.exp5.R;public class StaticReceiver extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.staticlayout);}public void send(View view){Intent intent = new Intent();//intent.setAction("com.eoeAndroid.broadcastReceiver.RECEIVER_ACTION");intent.putExtra("info","静态方法");intent.setComponent(new ComponentName(getPackageName(),"D:/Android/exp/exp5/app/src/main/java/com/example/exp5/ui/theme/MyReceiver.java"));sendBroadcast(intent);}
}

actionlayout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".ui.theme.ActionReceiver"><Buttonandroid:id = "@+id/actBroadcast"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "发送Broadcast"android:onClick="sendAct"/><Buttonandroid:id = "@+id/registerReceiver"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "创建"android:onClick="register"/><Buttonandroid:id = "@+id/unregisterReceiver"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "注销"android:onClick="unregister"/></LinearLayout>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".ui.theme.mainActivity"><Buttonandroid:id = "@+id/staticButton"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "静态方法"android:onClick="staticSys"/><Buttonandroid:id = "@+id/actionButton"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "动态方法"android:onClick="actionSys"/><Buttonandroid:id = "@+id/orderButton"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "有序广播"android:onClick="orderSys"/></LinearLayout>

staticlayout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".ui.theme.StaticReceiver"><Buttonandroid:id = "@+id/btnBroadcast"android:layout_width = "match_parent"android:layout_height = "wrap_content"android:text = "发送Broadcast"android:onClick="send"/>
</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"><applicationandroid:allowBackup="true"android:dataExtractionRules="@xml/data_extraction_rules"android:fullBackupContent="@xml/backup_rules"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:roundIcon="@mipmap/ic_launcher_round"android:supportsRtl="true"android:theme="@style/Theme.Exp5"tools:targetApi="31"><activityandroid:name=".ui.theme.mainActivity"android:exported="true"android:label="@string/app_name"android:theme="@style/Theme.Exp5"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity><activity android:name="com.example.exp5.ui.theme.StaticReceiver" /><activity android:name="com.example.exp5.ui.theme.ActionReceiver" /><receiver android:name="com.example.exp5.ui.theme.MyOrderReceiverOne" /><receiver android:name="com.example.exp5.ui.theme.MyReceiver" /><receiver android:name="com.example.exp5.ui.theme.MyOrderReceiverTwo" /><receiver android:name="com.example.exp5.ui.theme.MyOrderReceiverThree" /></application></manifest>