Android Combat Tips 44: hello,native!

Running the C program on Android is a bit strange for a kid's shoe to do the top app, because the current Android app development is still not going to go around Java.
But for the low-level driver developers, this is the same routine, because Android is a Linux branch, the bottom is the C/s world.

Sometimes in order to test some features, we will also write a C program that runs directly under Android Terminal. The prerequisite is the Android cross compiler and the root authority of the Android system.

Cross-compilation tool

The NDK has done a lot of work for us to develop the native program, and we've separated the Android cross-compiler tool from the NDK.
My system is 64-bit Ubuntu 14.04, so I downloaded the 64-bit NDK (Android-ndk-r10e-linux-x86_64.bin).

ndk$ chmod a+x android-ndk-r10e-linux-x86_64../android-ndk-r10e-linux-x86_64.bin

At this point, the NDK is ready to work. Let's change the cross-compiler tool out.

$./build/tools/make-standalone-toolchain.Sh--Platform=Android- + --Toolchain=Arm-linux-androideabi-4.9Copying prebuilt Binaries...Copying sysroot Headers andLibraries...Copying C++Runtime headers andLibraries...Creating Package File:/TMP/NDK-linc/arm-linux-androideabi-4.9.Tar.Bz2cleaning up...Done.

Find the right path to unzip:

build-tools$ tar jxvf arm-linux-androideabi-4.9.tar.bz2arm-linux-androideabi-4.9/...

Hello,native

Compiling c files main_test.c

#include <stdio.h>int main() {    printf("just a test,linc!hello, native!\n");    return0;}

Compile it:

$ ~/bin/build-tools/arm-linux-androideabi-4.9/bin/arm-linux-androideabi-gcc-o main_test main_test.c

Run up:
To run Main_test to Android:

$  adb push main_test/data/ App137  kb /S (6192  bytes in  0 . 043  s) $  adb shellroot  @hammerhead  :/ # cd data/app  root @hammerhead  :/data/app  # ls  main_ Testroot @hammerhead  :/data/app  #./main_test  just a Test,linc!hello, native!  

As we wish, the program runs smoothly, just as it does in a Linux system. Let's compile a program of two files.
Shooter.c

#include "shooter.h"#include <stdio.h>voidBubble_sort (int*Array,intN) {inti,j,tmp; for(i=0; i<n-1; i++) { for(j=n-1; j>i;j--) {if(Array[J-1]>Array[j]) {TMP =Array[J-1];Array[J-1]=Array[j];Array[J]=tmp; }        }    }}intAintA) {intn =Ten;intIint Array[] = { Wu, A,346,5, at, the,234,324, $,98}; for(i=0; i<n;i++) {printf("%d,",Array[i]); }printf("\ n"); Bubble_sort (Array, n);return Array[0];}

Shooter_tester.c

#include <stdio.h>#include "shooter.h"int main() {    int result = A(0);    printf("A result: %d\n",result);    return0;}

Compile run:

$ ~/bin/build-tools/arm-linux-androideabi-4.9/bin/arm-linux-androideabi-gcc-o Test shooter_tester.c SHOOTER.C$ ADB push test/data/app/143 KB/s (6344bytesinch 0.043S$ ADB shellroot@hammerhead:/ # CD Data/appRoot@hammerhead:/data/app #./test Wu, A,346,5, at, the,234,324, $,98,A Result: 5

Using random numbers

Next try to test the code in the "Make a dynamic link library" under Android and prepare to port it to the Android platform.
SHOOTER.C just generates random numbers using the above program with Rand and Srand.

#include "shooter.h"#include <time.h>#include <stdio.h>voidBubble_sort (int*Array,intN) {inti,j,tmp; for(i=0; i<n-1; i++) { for(j=n-1; j>i;j--) {if(Array[J-1]>Array[j]) {TMP =Array[J-1];Array[J-1]=Array[j];Array[J]=tmp; }        }    }}intAintA) {intn =Ten;intIint Array[n]; Srand (Time (NULL)); for(i=0; i<n;i++) {Array[I] = rand ()% -+1;printf("%d,",Array[i]); }printf("\ n"); Bubble_sort (Array, n);return Array[0];}

It's just a matter of compiling:

errorto‘srand‘errorto‘rand‘

The original is the random number method of the header file into a stdlib, the introduction is possible.
"Android Issue 45: Undefined reference to ' Srand '"
The results of the compilation run are as follows:

$ ~/bin/build-tools/arm-linux-androideabi-4.9/bin/arm-linux-androideabi-gcc-o Test shooter_tester.c SHOOTER.C$ ADB shellroot@hammerhead:/ # CD Data/appRoot@hammerhead:/data/app #./test -, the, the, -, -,Panax Notoginseng, About, -, the, the,A Result:  -Root@hammerhead:/data/app #./test -, -, -, +, -, $, One, -, -, the,A Result:  One

End

Now you can play Android as Linux. Have a nice day!

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Android Combat Tips 44: hello,native!