动态广播注册源码分析

2019年6月21日 170次阅读 来源: CAFFEBABE

说明：代码基于Android 23源码
本博客使用到的源码文件所在的位置（按出现顺序）：

   从源码的角度分析，动态广播的注册过程。作为广播的注册就是广播接受者接受什么样的广播的信息注册到ActivityManagerService中，让ActivityManagerService将该信息保存起来，这样当收到匹配的广播就会发送给该广播接收器。

动态广播的注册时通过使用

    public Intent registerReceiver(
        BroadcastReceiver receiver, IntentFilter filter) {
        return mBase.registerReceiver(receiver, filter);
    }

该方法是在activity里必须实现的，动态广播注册方法。借用罗大神的有关activity继承关系的图：
《动态广播注册源码分析》
registerReceiver的真正执行是在ContextImpl.java里面：

@Override
    public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {
        return registerReceiver(receiver, filter, null, null);
    }

    @Override
    public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter,
            String broadcastPermission, Handler scheduler) {//broadcastPermission、scheduler为null
        return registerReceiverInternal(receiver, getUserId(),
                filter, broadcastPermission, scheduler, getOuterContext());//getOuterContext()获取注册该广播的activity的上下文
    }

    private Intent registerReceiverInternal(BroadcastReceiver receiver, int userId,
            IntentFilter filter, String broadcastPermission,
            Handler scheduler, Context context) {
        IIntentReceiver rd = null;
        if (receiver != null) {
            if (mPackageInfo != null && context != null) {
                if (scheduler == null) {
                    scheduler = mMainThread.getHandler();
                }
                rd = mPackageInfo.getReceiverDispatcher(
                    receiver, context, scheduler,
                    mMainThread.getInstrumentation(), true);
            } else {
                if (scheduler == null) {
                    scheduler = mMainThread.getHandler();
                }
                rd = new LoadedApk.ReceiverDispatcher(
                        receiver, context, scheduler, null, true).getIIntentReceiver();
            }
        }
        try {
            final Intent intent = ActivityManagerNative.getDefault().registerReceiver(
                    mMainThread.getApplicationThread(), mBasePackageName,
                    rd, filter, broadcastPermission, userId);
            if (intent != null) {
                intent.setExtrasClassLoader(getClassLoader());
                intent.prepareToEnterProcess();
            }
            return intent;
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

最终进入到registerReceiverInternal方法中进行执行

    原文作者：CAFFEBABE
    原文地址: https://blog.csdn.net/lqktz/article/details/77914231
    本文转自网络文章，转载此文章仅为分享知识，如有侵权，请联系博主进行删除。
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