【源码】BroadcastReceiver广播发送流程

最新推荐文章于 2024-11-06 23:24:12 发布

xsic

最新推荐文章于 2024-11-06 23:24:12 发布

阅读量259

点赞数 1

文章标签： android

本文链接：https://blog.youkuaiyun.com/qq_38872414/article/details/118575288

版权

本文详细探讨了Android中BroadcastReceiver广播的发送流程，包括sendBroadcast、sendOrderedBroadcast和sendStickyBroadcast的使用。从sendBroadcastIntent开始，经过AMS的调度和处理，到ReceiverDispatcher的performReceive，最后在AMS的finishReceiver中结束。分析了动态和静态注册广播接收器的处理差异，并提出了performReceiveLocked中app.thread==null的疑问点。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

广播发送流程笔记

`ContextImpl`

1、sendBroadcast、sendOrderedBroadcast、sendStickyBroadcast

这里主要列举了三种发送的方法：普通广播、有序广播、粘性广播（过时）。
其中有序广播2是可以传入一个resultReceiver，可以确保这个receiver最后一定能收得到广播，这种发送方式是会创建一个InnerReceiver用来找到我们设置进去的resultReceiver的


    //-----------------普通广播---------------------//

    public void sendBroadcast(Intent intent, String receiverPermission, int appOp) {
   

		...

        try {
   
            ActivityManager.getService().broadcastIntent(
                    mMainThread.getApplicationThread(), intent, resolvedType, null,
                    Activity.RESULT_OK, null, null, receiverPermissions, appOp, null, false, false,
                    getUserId());
        }
        ...
    }


    //-----------------有序广播  1---------------------//


    void sendOrderedBroadcast(Intent intent,
            String receiverPermission, int appOp, BroadcastReceiver resultReceiver,
            Handler scheduler, int initialCode, String initialData,
            Bundle initialExtras, Bundle options) {
   
            
        IIntentReceiver rd = null;
        if (resultReceiver != null) {
   
            if (mPackageInfo != null) {
   
                if (scheduler == null) {
   
                    scheduler = mMainThread.getHandler();
                }
                rd = mPackageInfo.getReceiverDispatcher(
                    resultReceiver, getOuterContext(), scheduler,
                    mMainThread.getInstrumentation(), false);
            } else {
   
                if (scheduler == null) {
   
                    scheduler = mMainThread.getHandler();
                }
                rd = new LoadedApk.ReceiverDispatcher(
                        resultReceiver, getOuterContext(), scheduler, null, false).getIIntentReceiver();
            }
        }

		...

        try {
   
            ActivityManager.getService().broadcastIntent(
                mMainThread.getApplicationThread(), intent, resolvedType, rd,
                initialCode, initialData, initialExtras, receiverPermissions, appOp,
                    options, true, false, getUserId());
        }
        ...
    }



	//-----------------有序广播  2---------------------//

	@Override
    public void sendOrderedBroadcast(Intent intent, String receiverPermission) {
   
        warnIfCallingFromSystemProcess();
        String resolvedType = intent.resolveTypeIfNeeded(getContentResolver());
        String[] receiverPermissions = receiverPermission == null ? null
                : new String[] {
   receiverPermission};
        try {
   
            intent.prepareToLeaveProcess(this);
            ActivityManager.getService().broadcastIntent(
                    mMainThread.getApplicationThread(), intent, resolvedType, null,
                    Activity.RESULT_OK, null, null, receiverPermissions, AppOpsManager.OP_NONE,
                    null, true, false, getUserId());
        } catch (RemoteException e) {
   
            throw e.rethrowFromSystemServer();
        }
    }


    //------------------粘性广播（废弃）----------------------//


    @Override
    @Deprecated
    public void sendStickyBroadcast(Intent intent) {
   
    	...
        try {
   
            ActivityManager.getService().broadcastIntent(
                mMainThread.getApplicationThread(), intent, resolvedType, null,
                Activity.RESULT_OK, null, null, null, AppOpsManager.OP_NONE, null, false, true,
                getUserId());
        }
    }

`AMS`

1、sendBroadcastIntent

    public final int broadcastIntent(IApplicationThread caller,
            Intent intent, String resolvedType, IIntentReceiver resultTo,
            int resultCode, String resultData, Bundle resultExtras,
            String[] requiredPermissions, int appOp, Bundle bOptions,
            boolean serialized, boolean sticky, int userId) {
   
        enforceNotIsolatedCaller("broadcastIntent");
        synchronized(this) {
   
            intent = verifyBroadcastLocked(intent);

            final ProcessRecord callerApp = getRecordForAppLocked(caller);
            final int callingPid = Binder.getCallingPid();
            final int callingUid = Binder.getCallingUid();

            final long origId = Binder.clearCallingIdentity();
            try {
   
                //调用方法broadcastIntentLocked
                return broadcastIntentLocked(callerApp,
                        callerApp != null ? callerApp.info.packageName : null,
                        intent, resolvedType, resultTo, resultCode, resultData, resultExtras,
                        requiredPermissions, appOp, bOptions, serialized, sticky,
                        callingPid, callingUid, callingUid, callingPid, userId);
            } finally {
   
                Binder.restoreCallingIdentity(origId);
            }
        }
    }