动态注册监听时间变化.

MainActivity.kt

package com.example.broadcasttest

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.ResultReceiver
import android.widget.Toast

class MainActivity : AppCompatActivity() {
    lateinit var  timeChangeReceiver: TimeChangeReceiver
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val intentFilter=IntentFilter()
        intentFilter.addAction("android.intent.action.TIME_TICK")
        timeChangeReceiver=TimeChangeReceiver()
        registerReceiver(timeChangeReceiver,intentFilter)
    }
    override fun onDestroy() {
        super.onDestroy()
        unregisterReceiver(timeChangeReceiver)
    }
    inner  class TimeChangeReceiver : BroadcastReceiver(){
        override fun onReceive(context: Context?, intent: Intent?) {
            Toast.makeText(context,"Time has changed" ,Toast.LENGTH_SHORT).show()
        }
    }
}

静态注册实现开机启动

BootCompieteReciever.kt

package com.example.broadcasttest

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.widget.Toast

class BootCompieteReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {
        // This method is called when the BroadcastReceiver is receiving an Intent broadcast.
        Toast.makeText(context,"Boot Complete",Toast.LENGTH_SHORT).show()
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.broadcasttest">
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.BroadcastTest">
        <receiver
            android:name=".BootCompieteReceiver"
            android:enabled="true"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"/>
            </intent-filter>
        </receiver>
        <receiver
            android:name=".MyBroadcastReceiver"
            android:enabled="true"
            android:exported="true">
            <intent-filter>
                <action android:name="com.example.broadcasttest.MY_BROADCAST" />
            </intent-filter>
        </receiver>
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

发送标准广播

先写一个接收广播的 MyBroadcastReceiver

package com.example.broadcasttest

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.widget.Toast

class MyBroadcastReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        // This method is called when the BroadcastReceiver is receiving an Intent broadcast.
        Toast.makeText(context,"received in MyBroadcastReceiver",Toast.LENGTH_SHORT).show()
    }
}

在AndroidManifest.xml中添加相关配置.

  <intent-filter>
                <action android:name="com.example.broadcasttest.MY_BROADCAST" />
            </intent-filter>

用来接收广播.
接着在主界面处添加一个按钮用来触发广播.

<Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/button"
        android:text="Send Broadcast"/>

接着在MainActivity中添加相应的响应来发送广播.

package com.example.broadcasttest

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.ResultReceiver
import android.widget.Button
import android.widget.Toast

class MainActivity : AppCompatActivity() {
    lateinit var  timeChangeReceiver: TimeChangeReceiver
    lateinit var  button : Button
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val intentFilter=IntentFilter()
        intentFilter.addAction("android.intent.action.TIME_TICK")
        timeChangeReceiver=TimeChangeReceiver()
        registerReceiver(timeChangeReceiver,intentFilter)
        button=findViewById(R.id.button)
        button.setOnClickListener {
            val intent =Intent("com.example.broadcasttest.MY_BROADCAST")
            intent.setPackage(packageName)
            sendBroadcast(intent)
        }
    }
    override fun onDestroy() {
        super.onDestroy()
        unregisterReceiver(timeChangeReceiver)
    }
    inner  class TimeChangeReceiver : BroadcastReceiver(){
        override fun onReceive(context: Context?, intent: Intent?) {
            Toast.makeText(context,"Time has changed" ,Toast.LENGTH_SHORT).show()
        }
    }
}

发送有序广播.

另建一个Receiver

AnotherBroadcastReceiver

package com.example.broadcasttest

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.widget.Toast
class AnotherBroadcastReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        // This method is called when the BroadcastReceiver is receiving an Intent broadcast.
        Toast.makeText(context,"recevied in AnotherBroadcastReceiver",Toast.LENGTH_SHORT).show()
    }
}

将广播发送方式换成有序广播.

button.setOnClickListener {
            val intent =Intent("com.example.broadcasttest.MY_BROADCAST")
            intent.setPackage(packageName)
            sendOrderedBroadcast(intent,null)//第二个参数和权限有关.
        }

接着为了显示先后关系可以在AndroidManifest.xml中修改优先级.

<intent-filter android:priority="100">
                <action android:name="com.example.broadcasttest.MY_BROADCAST" />
            </intent-filter>