最近在開發(fā)過程中遇到一個(gè)需求，就是跨進(jìn)程的廣播通信，一番嘗試之后發(fā)現(xiàn)首先好像靜態(tài)注冊(cè)廣播的方式行不通了校翔，因?yàn)?strong>在Android 8.0的改動(dòng)中，限制了大部分的隱式廣播注冊(cè)廊蜒，常見的解決方案有兩種：一種是通過intent.setComponent方法將意圖改為顯式的。另一種方法就是改為動(dòng)態(tài)注冊(cè)了溅漾。
ps：關(guān)于Android 8.0中關(guān)于廣播的改動(dòng)可以查看官方文檔Android 8.0 行為變更中的后臺(tái)執(zhí)行限制部分山叮。
跨進(jìn)程的廣播發(fā)送與接收解決了之后，我還想添加一個(gè)權(quán)限限制樟凄，讓其他程序如果碰巧發(fā)送了同樣Action的廣播后我自己注冊(cè)的接收器不會(huì)接受聘芜，其他程序注冊(cè)的接收器不會(huì)收到我自己發(fā)出的同樣Action的廣播。但是經(jīng)過一番想當(dāng)然的嘗試之后失敗了缝龄，于是再次去翻文檔，然后通過demo測(cè)試實(shí)踐了一番挂谍。這里先簡(jiǎn)單小結(jié)一下=：
- 簡(jiǎn)單的權(quán)限限制分為兩類叔壤，一類是帶有權(quán)限的發(fā)送，用于限制接收器的口叙，只有申請(qǐng)了相應(yīng)權(quán)限的接收器才能接收到廣播炼绘。另一類是帶有權(quán)限的接收，用于限制發(fā)送廣播的一方妄田，在發(fā)送廣播時(shí)使用
sendBroadcast(Intent,String)方法發(fā)送廣播俺亮。 - 如果想要實(shí)現(xiàn)A應(yīng)用發(fā)送的廣播只有B應(yīng)用可以接收到驮捍，B應(yīng)用只能接收到A應(yīng)用發(fā)出的廣播(注意這里雖然兩句話表述好像一致，但是其實(shí)包含的情況是不同的)脚曾，應(yīng)該就需要在注冊(cè)廣播時(shí)通過
permissionGroup以及protectionLevel等屬性去做更近一步的限制了东且，具體的實(shí)現(xiàn)這里就沒有再繼續(xù)下去了，后面有時(shí)間的話可以通過文檔permission對(duì)這兩個(gè)屬性的介紹嘗試一下本讥。
下面根據(jù)官方文檔廣播概況以及具體的Demo實(shí)際感受一下兩種通過權(quán)限限制的廣播：
帶權(quán)限的發(fā)送
這種方式可以用來限制廣播接收器珊泳，在發(fā)送廣播的一方通過sendBroadcast(Intent,String)方法發(fā)送他廣播，然后聲明了相應(yīng)權(quán)限的的一方中注冊(cè)的廣播接收器才能收到廣播拷沸。使用這種方式權(quán)限需要聲明在廣播發(fā)送方色查。
Project A -- (BroadcastTest1):
<!-- AndroidManifest.xml -->
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.broadcasttest1">
<!-- 聲明權(quán)限 -->
<permission android:name="com.yu.hu.permissions.BUGREPORT"/>
<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/AppTheme">
...
</application>
</manifest>
class MainActivity : AppCompatActivity() {
companion object {
const val TAG = "MainActivity"
const val ACTION = "com.yu.hu.action.BUGREPPORT"
const val PERMISSION = "com.yu.hu.permissions.BUGREPORT"
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val button = findViewById<Button>(R.id.send_btn)
//添加button點(diǎn)擊事件
button.setOnClickListener {
val intent = Intent(ACTION)
intent.putExtra("test", "test")
Log.d(TAG, "send BroadcastReceiver with permission")
//帶有權(quán)限的發(fā)送 接收方必須申請(qǐng)相應(yīng)權(quán)限才能正常接受到
sendBroadcast(intent,PERMISSION)
}
}
}
Project B -- (BroadcastTest2):
<!-- AndroidManifest.xml -->
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.broadcasttest2">
<!-- 申請(qǐng)權(quán)限 -->
<uses-permission android:name="com.yu.hu.permissions.BUGREPORT" />
<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/AppTheme">
...
</application>
</manifest>
class BugReportReceiver : BroadcastReceiver() {
companion object {
const val TAG = "BugReportReceiver"
const val ACTION = "com.yu.hu.action.BUGREPPORT"
const val PERMISSION = "com.yu.hu.permissions.BUGREPORT"
}
override fun onReceive(context: Context?, intent: Intent?) {
val value = intent?.getStringExtra("test")
Log.d(TAG, "onReceive: msg = $value")
Toast.makeText(context, "msg2 = $value", Toast.LENGTH_SHORT).show()
}
}
class MainActivity : AppCompatActivity() {
companion object {
const val TAG = "MainActivity2"
const val ACTION = "com.yu.hu.action.BUGREPPORT"
const val PERMISSION = "com.yu.hu.permissions.BUGREPORT"
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val ifl = IntentFilter()
ifl.addAction(BugReportReceiver.ACTION)
registerReceiver(BugReportReceiver(), ifl)
}
}
Project C -- (BroadcastTest3):
class BugReportReceiver : BroadcastReceiver() {
companion object {
const val TAG = "BugReportReceiver"
const val ACTION = "com.yu.hu.action.BUGREPPORT"
const val PERMISSION = "com.yu.hu.permissions.BUGREPORT"
}
override fun onReceive(context: Context?, intent: Intent?) {=
val value = intent?.getStringExtra("test")
Log.d(TAG, "onReceive: msg = $value")
Toast.makeText(context, "msg2 = $value", Toast.LENGTH_SHORT).show()
}
}
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
registerReceiver(BugReportReceiver(), IntentFilter(BugReportReceiver.ACTION))
}
}
點(diǎn)擊Button后輸出結(jié)果：
2020-07-10 12:51:27.155 25951-25951/com.example.broadcasttest1 D/MainActivity: send BroadcastReceiver with permission
2020-07-10 12:51:27.157 31322-31336/? W/BroadcastQueue: Permission Denial: receiving Intent { act=com.yu.hu.action.BUGREPPORT flg=0x10 (has extras) } to ProcessRecord{3b20417 25865:com.example.boradcasttest3/u0a164} (pid=25865, uid=10164) requires com.yu.hu.permissions.BUGREPORT due to sender com.example.broadcasttest1 (uid 10155)
2020-07-10 12:51:27.161 25907-25907/com.example.broadcasttest2 D/BugReportReceiver: onReceive: msg = test
可以看到只有B收到了廣播了而C沒有收到，因?yàn)?strong>B在AndroidManifest.xml中申請(qǐng)了權(quán)限撞芍，而C沒有秧了，所以報(bào)了Permission Denial的錯(cuò)誤。在C中也申請(qǐng)了權(quán)限后就同樣能接收到廣播了序无。
帶權(quán)限的接收
這種方式可以用來限制發(fā)送廣播的一方验毡，只有申請(qǐng)了相應(yīng)的權(quán)限才能成功發(fā)送廣播。使用這種方式權(quán)限需要聲明在廣播接收器的注冊(cè)方愉镰。
Project A -- (BroadcastTest1): - 申請(qǐng)權(quán)限
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.broadcasttest1">
<uses-permission android:name="com.test.permission.receiver"/>
...
</manifest>
class MainActivity : AppCompatActivity() {
companion object {
const val TAG = "MainActivity"
const val ACTION = "com.yu.hu.action.BUGREPPORT"
const val PERMISSION = "com.yu.hu.permissions.BUGREPORT"
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val button = findViewById<Button>(R.id.send_btn)
button.setOnClickListener {
val intent = Intent(ACTION)
intent.putExtra("test", "test")
Log.d(TAG, "send Broadcast with permission")
sendBroadcast(intent)
}
}
}
Project B -- (BroadcastTest2): - 不申請(qǐng)權(quán)限
class MainActivity : AppCompatActivity() {
companion object {
const val TAG = "MainActivity2"
const val ACTION = "com.yu.hu.action.BUGREPPORT"
const val PERMISSION = "com.yu.hu.permissions.BUGREPORT"
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val button = findViewById<Button>(R.id.send_btn)
button.setOnClickListener {
val intent = Intent(ACTION)
intent.putExtra("test", "test")
Log.d(TAG, "send Broadcast without permission")
//不申請(qǐng)權(quán)限發(fā)送
sendBroadcast(intent)
}
}
}
Project C -- (BroadcastTest3): - 聲明權(quán)限并在注冊(cè)時(shí)添加權(quán)限
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.boradcasttest3">
<permission android:name="com.test.permission.receiver"/>
...
</manifest>
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
registerReceiver(BugReportReceiver(), IntentFilter(BugReportReceiver.ACTION), "com.test.permission.receiver", null)
}
}
在A中發(fā)送廣播：
2020-07-10 14:07:36.187 12843-12843/com.example.broadcasttest1 D/MainActivity: send Broadcast with permission
2020-07-10 14:07:36.191 12600-12600/com.example.boradcasttest3 D/BugReportReceiver: onReceive2: msg = test
成功發(fā)送也成功接收處理米罚。下面是在B中發(fā)送廣播的日志：
2020-07-10 14:08:04.368 13003-13003/com.example.broadcasttest2 D/MainActivity2: send Broadcast without permission
2020-07-10 14:08:04.370 31322-31336/? W/BroadcastQueue: Permission Denial: broadcasting Intent { act=com.yu.hu.action.BUGREPPORT flg=0x10 (has extras) } from com.example.broadcasttest2 (pid=13003, uid=10162) requires com.test.permission.receiver due to registered receiver BroadcastFilter{37dbe8b u0 ReceiverList{7706c5a 12600 com.example.boradcasttest3/10164/u0 remote:8530405}}
發(fā)送之后報(bào)了Permission Denial，所以接收器沒有接收到這條廣播丈探。
