android 純c/c++開發（轉）

本文轉載自查看原文 2014-08-15 14:08 4275 Android-NDK

轉載自： http://jingyan.baidu.com/article/a501d80cf394dfec630f5e85.html

android 自ndk r8出來以后，就開始支持純c/c++開發，android 的純 c/c++ 開發更有些想 win32 開發，只不過是 WinMain 變成了 android_main, 消息處理函數變成了兩個，下面開始詳細的介紹如何進行純 c/c++開發，里面附帶一個多點觸屏的例子，希望對大家有用，謝謝！

工具/原料

win7 x64
jdk1.8.0_11
adt-bundle-windows-x86_64-20140702
android-ndk-r10

新建一個Natvie工程

1

打開eclipse；
2

打開菜單->File->New->Android Application；
3

設置工程名，sdk版本，注意：主題設置為 None，點擊next；
4

Configure Project 是取消 Create activity 的復選框，點擊next；
5

Configure the attributes of the icon set，直接點擊 next；
6

Select whether to create an activity, and if so, what kind of activity. 點擊 finish即可；
7

工程便創建出來了

END

配置Makefile

1

右鍵工程NativeTest->彈出菜單->Android Tools->Add Native Support...
2

Settings for generated native components for project.界面直接點擊Finish
3

將 android.mk 的內容補充完整：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := NativeTest

LOCAL_SRC_FILES := NativeTest.cpp

LOCAL_LDLIBS := -llog -landroid

LOCAL_STATIC_LIBRARIES := android_native_app_glue

include $(BUILD_SHARED_LIBRARY)

$(call import-module,android/native_app_glue)
4

增加一個 Application.mk 文件（這一步可選），並寫入：

APP_ABI := x86

APP_CPPFLAGS := --std=c++11

NDK_TOOLCHAIN_VERSION := 4.8

END

代碼部分

1

1、android_main：這個函數類似於win32開發的WinMain函數

2、app->onAppCmd = onAppCmd;

app->onInputEvent = onInputEvent;

類似於win32中設置窗口的回掉函數

3、

while ((ident=ALooper_pollAll(-1, NULL, &events,

(void**)&source)) >= 0) {

// Process this event.

if (source != NULL) {

source->process(app, source);

}

// Check if we are exiting.

if (app->destroyRequested != 0) {

return;

}

}

這一段類似於win32的消息循環

4、為了方便大家粘貼，android_main 函數的代碼如下：

void android_main(struct android_app* app) {

// Make sure glue isn't stripped.

app_dummy();

app->onAppCmd = onAppCmd;

app->onInputEvent = onInputEvent;

while (1) {

int ident;

int events;

struct android_poll_source* source;

while ((ident=ALooper_pollAll(-1, NULL, &events,

(void**)&source)) >= 0) {

// Process this event.

if (source != NULL) {

source->process(app, source);

}

// Check if we are exiting.

if (app->destroyRequested != 0) {

return;

}

}

}

}
2

onAppCmd 描述的是真個activity的生命周期，類似於win32開發的消息處理回掉函數：

static void onAppCmd(struct android_app* app, int32_t cmd) {

switch (cmd) {

case APP_CMD_SAVE_STATE:

// The system has asked us to save our current state. Do so.

__android_log_print(ANDROID_LOG_DEBUG, "fuke", "engine_handle_cmd APP_CMD_SAVE_STATE");

break;

case APP_CMD_INIT_WINDOW:

// The window is being shown, get it ready.

__android_log_print(ANDROID_LOG_DEBUG, "fuke", "engine_handle_cmd APP_CMD_INIT_WINDOW");

break;

case APP_CMD_TERM_WINDOW:

__android_log_print(ANDROID_LOG_DEBUG, "fuke", "engine_handle_cmd APP_CMD_TERM_WINDOW");

break;

case APP_CMD_GAINED_FOCUS:

// When our app gains focus, we start monitoring the accelerometer.

__android_log_print(ANDROID_LOG_DEBUG, "fuke", "engine_handle_cmd APP_CMD_GAINED_FOCUS");

break;

case APP_CMD_LOST_FOCUS:

// When our app loses focus, we stop monitoring the accelerometer.

// This is to avoid consuming battery while not being used.

__android_log_print(ANDROID_LOG_DEBUG, "fuke", "engine_handle_cmd APP_CMD_LOST_FOCUS");

break;

}

}
3

onInputEvent 主要是用來觸屏相關事件，也類似於win32開發的消息處理回掉函數，函數有兩部分組成：

1、檢測多點觸屏，並通過logcat打印出多點觸屏的信息；

2、控制屏幕顏色變化，每次松開手時顏色變化

3、為方便大家粘貼，onInputEvent函數的代碼記錄如下：

static int32_t onInputEvent(struct android_app* app, AInputEvent* event) {

if (AInputEvent_getType(event) == AINPUT_EVENT_TYPE_MOTION) {

int nNum = AMotionEvent_getPointerCount(event);

char szTrace[1024] = {0};

sprintf (szTrace, "engine_handle_input num=[%d]", nNum);

for (int nIdx = 0; nIdx < nNum; nIdx++)

{

int nX = AMotionEvent_getX(event, 0);

int nY = AMotionEvent_getY(event, 0);

sprintf (strrchr(szTrace, 0), " (%d %d)", nX, nY);

}

__android_log_print(ANDROID_LOG_DEBUG, "colorspace",

"%s", szTrace);

if (AKeyEvent_getAction(event) != AKEY_EVENT_ACTION_UP)

return 1;

ANativeWindow_Buffer nativeWindow = {0};

int nRet = ANativeWindow_lock(app->pendingWindow, &nativeWindow, NULL);

int nArea = nativeWindow.width * nativeWindow.height;

unsigned long* pdwScreen = (unsigned long*)nativeWindow.bits;

static int s_nClr = 0;

unsigned long pdwClr[] = {

0x00000000, 0x000000ff, 0x0000ffff, 0x0000ff00,

0x00ffff00, 0x00ff0000, 0x00ff00ff, 0x00ffffff};

s_nClr ++;

if (s_nClr > sizeof(pdwClr) / sizeof(unsigned long))

s_nClr = 0;

for (int nIdx = 0; nIdx < nArea; nIdx++)

{

pdwScreen[nIdx] = pdwClr[s_nClr];

}

ANativeWindow_unlockAndPost(app->pendingWindow);

return 1;

}

return 0;

}

END

設置工程屬性

1

1、打開 AndroidManifest.xml

2、打開 Application 分頁

3、增加一個 Activity

如下所示：
2

1、選擇右邊的 Browse;

2、取消 "Display classes from sources of ..." 前面的復選框;

3、在搜索欄輸入"na"，選中列出來的 "NativeActivity"

4、點擊OK

效果如下：
3

1、選中 android.app.nativeActivity

2、點擊 add

3、選擇 Meta Data

4、點擊Ok
4

輸入：

android:name="android.app.lib_name"

android:value="NativeTest"
5

1、選中 android.app.nativeActivity

2、點擊 add

3、選擇 Intent Filter

4、點擊Ok
6

1、選中 Intent Filter

2、點擊 add

3、選擇 Action

4、點擊Ok

5、設置 android:name="android.intent.action.MAIN"
7

1、選中 Intent Filter

2、點擊 add

3、選擇 Category

4、點擊Ok

5、設置 android:name="android.intent.category.LAUNCHER"

END