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

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;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.actionlayout);
    }
    public void sendAct(View view){
        Intent intent=new Intent();       //实例化Intent
        intent.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 {

    @Override
    protected 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 {
    @Override
    public 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 {
    @Override
    public 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 {
    @Override
    public 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() {
    }
    @Override
    public 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 {
    @Override
    protected 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

activity_main.xml

staticlayout.xml

AndroidManifest.xml

结果展示

暂且如此吧。