Activity Manager Service

// Activity.startActivity的核心流程
public void startActivity(Intent intent) {
    startActivity(intent, null);
}
 
public void startActivity(Intent intent, Bundle options) {
    if (options != null) {
        startActivityForResult(intent, -1, options);
    } else {
        startActivityForResult(intent, -1);
    }
}

private final boolean attachApplicationLocked(IApplicationThread thread,
        int pid, int callingUid, long startSeq) {
    // 查找进程记录
    ProcessRecord app = mPidsSelfLocked.get(pid);
    
    // 绑定应用进程
    thread.bindApplication(processName, appInfo, providers,
            app.instrumentationClass,
            profilerInfo, app.instrumentationArguments,
            app.instrumentationWatcher, app.instrumentationUiAutomationConnection,
            testMode, enableOpenGlTrace, isRestrictedBackupMode, enableTrackAllocation,
            isAutoFillCompatibilityEnabled, app.mBoundClientUid, null,
            new Configuration());
}

// AndroidManifest.xml配置
<activity
    android:name=".MainActivity"
    android:launchMode="singleTask"
    android:taskAffinity="com.example.task"/>
 
// 代码中启动
Intent intent = new Intent(this, SecondActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);