Android mk输出日志方法

makefile文件控制整个工程的编译规则，比如指定需要生成哪些目标文件，指明生成这些目标文件依赖哪些源文件，指明生成的目标文件放在哪个文件夹下等等。而make就是一个命令工具，可以解析makefile文件中的指令的一个命令工具。

android.mk也是一样的功能，只不过它是android编译环境下的一种特殊的“makefile”文件, 它是经过了android编译系统处理的。android.mk文件最终还是要被android编译系统层层解析，转化为make命令能够读懂的格式，从而调用gcc编译器进行编译。

1、 在 Android.mk里打印信息有三种方法：

a. $(info string) 打印正常输入信息

b. $(warning string) 打印警告信息

c. $(error string) 打印错误信息

以上三种打印方式：

a. 各个打印方式的string里都可以带上变量；

b. 如果遇到error打印，将会停止编译进程。

c.warning 的打印带有 warning 标志，info 打印不带有任何标志。

2、 举例说明各个打印函数的方法,以下以packages/apps/Music/Android.mk为例，内容如下：

LOCAL_PATH:= $(call my-dir)

$(warning "Warning Just for Test LOCAL_PATH is $(LOCAL_PATH)")
$(info "Info Just for Test LOCAL_PATH is $(LOCAL_PATH)")
include $(CLEAR_VARS) LOCAL_MODULE_TAGS := optional
LOCAL_SRC_FILES := $(call all-java-files-under, src) \
src/com/android/music/IMediaPlaybackService.aidl
LOCAL_PACKAGE_NAME := Music
LOCAL_SDK_VERSION := current
LOCAL_CERTIFICATE := platform
LOCAL_PROGUARD_FLAG_FILES := proguard.flags

include $(BUILD_PACKAGE)

# Use the folloing include to make our test apk.

include $(call all-makefiles-under,$(LOCAL_PATH))

输出：

ninja: no work to do.

[1/2] glob packages/apps/*/Android.bp

ninja: no work to do.

packages/apps/Music/Android.mk was modified, regenerating...

Saved manifest to commit_id.xml

packages/apps/Music/Android.mk:2: warning: "Warning Just for Test LOCAL_PATH is

packages/apps/Music"

"Info Just for Test LOCAL_PATH is packages/apps/Music"

PRODUCT_COPY_FILES device/rockchip/common/init.rk30board.usb.rc:root/init.rk30board.usb.rc ignored.

No private recovery resources for TARGET_DEVICE rk3328_box

[ 50% 1/2] glob packages/apps/*/Android.bp

[100% 1/1] Ensuring Jack server is installed and started

Jack server already installed in "/home/seven/.jack-server"

Server is already running

#### build completed successfully (28 seconds) ####