framework(一)：ActivityThread-笔记

ActivityThread 的功能是管理应用程序进程中的主线程，包括调度和执行Activity，broadcasts以及其它的请求操作。

当用户打开一个应用程序时，会由AMS（ActivityMangerService）创建一个ActivityThread，当然ActivityThread并不是一个线程类，但是其所在的线程就是主线程，也就是常说的UI 线程。

 

 

public static void main(String[] args) {
5185        SamplingProfilerIntegration.start();
5186
5187        // CloseGuard defaults to true and can be quite spammy.  We
5188        // disable it here, but selectively enable it later (via
5189        // StrictMode) on debug builds, but using DropBox, not logs.
5190        CloseGuard.setEnabled(false);
5191
5192        Environment.initForCurrentUser();
5193
5194        // Set the reporter for event logging in libcore
5195        EventLogger.setReporter(new EventLoggingReporter());
5196
5197        Security.addProvider(new AndroidKeyStoreProvider());
5198
5199        // Make sure TrustedCertificateStore looks in the right place for CA certificates
5200        final File configDir = Environment.getUserConfigDirectory(UserHandle.myUserId());
5201        TrustedCertificateStore.setDefaultUserDirectory(configDir);
5202
5203        Process.setArgV0("<pre-initialized>");
5204
5205        Looper.prepareMainLooper();
5206
5207        ActivityThread thread = new ActivityThread();
5208        thread.attach(false);
5209
5210        if (sMainThreadHandler == null) {
5211            sMainThreadHandler = thread.getHandler();
5212        }
5213
5214        AsyncTask.init();
5215
5216        if (false) {
5217            Looper.myLooper().setMessageLogging(new
5218                    LogPrinter(Log.DEBUG, "ActivityThread"));
5219        }
5220
5221        Looper.loop();
5222
5223        throw new RuntimeException("Main thread loop unexpectedly exited");
5224    }
5225}

由main方法进入消息循环。