What's behind the Android apps. 研究Android底層(包含framework)的重要性是什麼? 請看Jollen's presentation.

2. Jollen’s Consulting
,
,
,
: www.jollen.org/consulting

3. Jollen’s Consulting
ta@jollen.org
[
]
Jollen’s Consulting Team

4. Presentation Training Coaching

6. low-level

7. Android Kernel Features

8. Android Kernel Features

9. Android Kernel
•Binder
•Ashmem (Android shared memory)
•PMEM (Processor memory allocator)
•logcat (Android Logger)
•wakelock (Android Power Management)
•Alarm

10. Key Features 2.6.23 2.6.25 2.6.27 2.6.29
1 Alarm Driver O O O O
2 Android Logger O O O O
3 Low Memory Killer O O O O
4 Power Management O O O O
5 USB Gadget O O O O
6 ASHMEM X O O O
7 PMEM X X O O
8 x86 Support X X O O
9 ./drivers/staging/Android/ X X X O

12. Android Toolchain
•android-toolchain-20081019
•http://android.git.kernel.org/pub/
•gcc 4.2.1 / binutils 2.17 / gdb 6.6
•ARMV5te+
•ABI: EABI, AAPCS
•--with-float=soft --with=fpu-vfp
•--enable-threads (single)

14. Application Developers
Applications change
Application Framework
Surface Manager Dalvik VM
System
Media Framework Shared Libraries
Image
Linux Kernel

15. Product Branch Maintainer
Applications
Application Framework
Surface Manager Dalvik VM
rebuild
Media Framework Shared Libraries
Linux Kernel

16. Hardware Developing
Applications
Application Framework
Surface Manager Dalvik VM
change
Media Framework Shared Libraries
Linux Kernel change

17. Architecture Porting
Applications
Application Framework
Surface Manager Dalvik VM
porting
Media Framework Shared Libraries
Linux Kernel

19. • Application Developers

20. • Application Developers
• Product Branch Maintainer

21. • Application Developers
• Product Branch Maintainer
• Hardware Developing

22. • Application Developers
• Product Branch Maintainer
• Hardware Developing
• Architecture Porting

23. Android Framework

24. Android Framework

25. • The best way to write good, efficient code for
embedded systems is to understand what the
code you write really does. --Android Dev Guide

27. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}

28. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}
private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
setContentView(R.layout.main);
}

30. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
UI;
SensorManager;
}

31. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
UI;
SensorManager;
}
private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SensorManager;
UI;
}

33. •

35. public class TunitBill extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Debug.startMethodTracing("TunitB");
CharSequence time = Long.toString(SystemClock.elapsedRealtime());
Debug.stopMethodTracing();
}
}

36. public class TunitBill extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Debug.startMethodTracing("TunitB");
CharSequence time = Long.toString(SystemClock.elapsedRealtime());
Debug.stopMethodTracing();
}
}
•
method-level

37. method-level
low-level

40. • TraceView method (method
tracing)

42. Avoid Creating Objects
Use Native Methods
Prefer Virtual Over Interface
Prefer Static Over Virtual
Avoid Internal Getters/Setters
Cache Field Lookups
Declare Constants Final
Use Enhanced For Loop Syntax With Caution
Avoid Enums
Use Package Scope with Inner Classes
Avoid Float

43. Avoid Creating Objects
Use Native Methods
Prefer Virtual Over Interface
Prefer Static Over Virtual
Avoid Internal Getters/Setters
Cache Field Lookups
Declare Constants Final
Use Enhanced For Loop Syntax With Caution
Avoid Enums
Use Package Scope with Inner Classes
Avoid Float
• Designing for Performance -- Android Dev
Guide

44. Android Tracing API
android.os.Debug

45. Debug.startMethodTracing("TunitB");
/* writing codes to profile */
Debug.stopMethodTracing();
Android Tracing API
android.os.Debug

47. public class TunitChris extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button)findViewById(R.id.btn);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
}
});
}
}

49. •

50. Acitivty
View.OnClickListener
Android Copyright (c) 2009 Jollen’s Consulting . www.jollen.org/consulting

52. public class TunitChris extends Activity implements
View.OnClickListener {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button)findViewById(R.id.btn);
button.setOnClickListener(this);
}
public void onClick(View v) {
Toast.makeText(
this,
"Yes.",
Toast.LENGTH_LONG).show();
}
}

54. button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
}
});

56. public class TunitChris extends Activity implements
View.OnClickListener

58. •

59. SensorManager

60. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}
SensorManager

61. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void onStop() {
super.onStop();
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}

62. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void onStop() {
super.onStop();
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}
better

63. Source: Android SDK

65. Launcher

66. method-level

67. Android Driver Model
HAL

68. Android Driver Model
HAL

69. native C programs
glibc & shared libs
S!"#$%!&'((
Kernel
Hardware

70. Android Framework
Application
JNI
S!"#$%!&'((
bionic & shared libs
Kernel
Hardware

71. public class Sensors extends Activity {
...
private SensorManager mSensorManager;
...
@Override
protected void onCreate(Bundle savedInstanceState) {
// Be sure to call the super class.
super.onCreate(savedInstanceState);
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}
...
}

74. class SensorService extends ISensorService.Stub {
...
private static native int _sensors_control_init();
private static native ParcelFileDescriptor
_sensors_control_open();
private static native boolean
_sensors_control_activate(int sensor, boolean activate);
private static native int _sensors_control_set_delay
(int ms);
}
at framework/base/services/java/SensorService.java

75. class SensorService extends ISensorService.Stub {
...
public SensorService(Context context) {
if (localLOGV) Log.d(TAG, "SensorService
startup");
_sensors_control_init();
mNotificationManager = (NotificationManager)
context.getSystemService
(Context.NOTIFICATION_SERVICE);
mContext = context;
}
...
}
at framework/base/services/java/SensorService.java

76. static JNINativeMethod gMethods[] = {
{"_sensors_control_init", "()I", (void*) android_init },
{"_sensors_control_open", "()Landroid/os/
ParcelFileDescriptor;",
(void*) android_open },
{"_sensors_control_activate", "(IZ)Z", (void*)
android_activate },
{"_sensors_control_wake", "()I", (void*)
android_data_wake },
{"_sensors_control_set_delay","(I)I", (void*)
android_set_delay },
};

77. static jint
android_init(JNIEnv *env, jclass clazz)
{
sensors_module_t* module;
if (hw_get_module(SENSORS_HARDWARE_MODULE_ID, (const hw_module_t**)
&module) == 0) {
if (sensors_control_open(&module->common, &sSensorDevice) == 0)
{
const struct sensor_t* list;
int count = module->get_sensors_list(module, &list);
return count;
}
}
return 0;
}
static inline int sensors_control_open(const struct hw_module_t*
module, struct sensors_control_device_t** device) {
return module->methods->open(module,
SENSORS_HARDWARE_CONTROL, (struct hw_device_t**)
device);
}

82. Application Context
getSystemService
Create Manager
App
App View
!"#$%& IStubService
Manager
framework/base/services/java
alvik VM IStubService

83. SensorManager

84. private SensorManager mSensorManager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSensorManager = (SensorManager) getSystemService
(SENSOR_SERVICE);
}
SensorManager

86. public Object getSystemService(String name) {
if (WINDOW_SERVICE.equals(name)) {
return WindowManagerImpl.getDefault();
} else if (LAYOUT_INFLATER_SERVICE.equals(name)) {
synchronized (mSync) {
LayoutInflater inflater = mLayoutInflater;
if (inflater != null) {
return inflater;
}
mLayoutInflater = inflater =
PolicyManager.makeNewLayoutInflater(getOuterContext());
return inflater;
}
} else if (ACTIVITY_SERVICE.equals(name)) {
return getActivityManager();
} else if (ALARM_SERVICE.equals(name)) {
return getAlarmManager();
..
} else if ( SENSOR_SERVICE.equals(name)) {
return getSensorManager();
}
...
}
Android Copyright (c) 2009 Jollen’s Consulting . www.jollen.org/consulting

89. private SensorManager getSensorManager() {
synchronized (mSync) {
if (mSensorManager == null) {
mSensorManager = new SensorManager
(mMainThread.getHandler().getLooper());
}
}
return mSensorManager;
}

90. Application Context
getSystemService
Create Manager
App
App View
!"#$%& IStubService
Manager
framework/base/services/java
Dalvik VM IStubService
Service/Java
framework/base/services/java
register
JNI Table
Android server
VM Onload App Onload
Android Copyright (c) 2009 Jollen’s Consulting . www.jollen.org/consulting

92. • device driver

93. !"#$%&
Manager
framework/base/services/java
Dalvik VM IStubService
Service/Java
framework/base/services/java
register
JNI Table
Android server
Service/JNI
framework/base/services/jni
HAL
hardware/libhardware
HAL Stub
sysfs
/sys
VM Onload App Onload
Android Copyright (c) 2009 Jollen’s Consulting . www.jollen.org/consulting

94. at framework/base/services/java/SensorService.java

95. class SensorService extends ISensorService.Stub {
...
public SensorService(Context context) {
if (localLOGV) Log.d(TAG, "SensorService
startup");
_sensors_control_init();
mNotificationManager = (NotificationManager)
context.getSystemService(Context.NOTIFICATION_SERVICE);
mContext = context;
}
...
}
at framework/base/services/java/SensorService.java

96. Android Copyright (c) 2009 Jollen’s Consulting . www.jollen.org/consulting

97. VFS
Driver D
Driver B
Driver A
Driver E
Driver C
Copyright (c) 2009 Jollen’s Consulting, www.jollen.org/consulting Embedded Linux

98. kernel
buses devices classes firmware kobject
Core Driver Model – Subsystems (ksets…) /sys
Driver D
Driver B
Driver A
Driver E
Driver C
Copyright (c) 2009 Jollen’s Consulting, www.jollen.org/consulting Embedded Linux

99. Android

100. Android
• Launcher Model
• getSystemService
• Framework
• HAL module sysfs

101. high-level
low-level

102. high-level
low-level

103. high-level
low-level

104. high-level
architect-level
low-level

106. architect

107. Android Source Tree

108. Android Source Tree
|-- Makefile Makefile
|-- bionic Bionic 义 这
|-- bootloader
|-- build build 录 内
脚
|-- dalvik JAVA虚拟
|-- development 发
|-- external
|-- frameworks
|-- hardware
|-- kernel Linux2.6
|-- packages Android
|-- prebuilt Android 脚
|-- recovery
`-- system Android

109. <company_name>
<board_name>
+ Android.mk
+ product_config.mk
+ system.prop
products
+ AndroidProducts.mk
+ <first_product_name>.mk
+ <second_product_name>.mk
Android Jollen’s Consulting. www.jollen.org/consulting

110. 1. Get Google Android
$ repo init -u git://android.git.kernel.org/platform/manifest.git -b cupcake
$ repo sync
2. Manifest file.
<manifest>
...
<project name="platform/vendor/asus/eee_701" path="vendor/asus/
eee_701"/>
...
</manifest>
3. Get EeePC platform.
$ repo sync
4. Build Android image.
$ TARGET_ARCH=x86 TARGET_PRODUCT=eee_701
DISABLE_DEXPREOPT=true make -j2 installer_img
5. Create USB boot stick.
Use make-live script. https://review.source.android.com/Gerrit#change,6475
Android Jollen’s Consulting. www.jollen.org/consulting

111. Build EeePC 701 Product Tips # Google API issue
$(call inherit-product, $(SRC_TARGET_DIR)/product/generic.mk)
PRODUCT_NAME := eee_701
PRODUCT_DEVICE := eee_701
PRODUCT_POLICY := android.policy_mid
PRODUCT_PROPERTY_OVERRIDES +=
ro.com.android.dataroaming=true
Cupcake将Google APIs add-ons
Android Jollen’s Consulting. www.jollen.org/consulting

112. Build EeePC 701 Product Tips # e2fsprogs issue
external/e2fsprogs/Android.mk:
--- a/Android.mk
+++ b/Android.mk
@@ -1,3 +1,3 @@
ifneq ($(TARGET_SIMULATOR),true)
-# include $(call all-subdir-makefiles)
+ include $(call all-subdir-makefiles)
endif
Android Jollen’s Consulting. www.jollen.org/consulting

113. boot.img
installer.img
ramdisk.img
system.img
userdata.img
Android Jollen’s Consulting. www.jollen.org/consulting

114. Android 随
$ make-live
Android Jollen’s Consulting. www.jollen.org/consulting

115. AMD PCnet32 PCI support
VESA VGA graphics support
VGA 8x8 font
VGA 8x16 font
Android Jollen’s Consulting. www.jollen.org/consulting

116. $ VBoxManage convertromraw -format VDI ./installer.img ./android.vdi
Android Jollen’s Consulting. www.jollen.org/consulting

117. device/system/init
device/system/init/init.c
/etc/init.rc
动mount file system ( /etc/fstab)
Android Jollen’s Consulting. www.jollen.org/consulting

118. /system/bin/logd
/sbin/adbd
/system/bin/usbd
/system/bin/debuggerd
/system/bin/rild
/system/bin/app_process
/system/bin/runtime
/system/bin/dbus-daemon
system_server
Android Jollen’s Consulting. www.jollen.org/consulting

119. • Application Developers
• Product Branch Maintainer
• Hardware Developingframework, app
LED : kernel, hal,
• Architecture Porting

120. www.jollen.org/consulting
Jollen@jollen.org