My test code to run native ARM C binaries on Android

gistfile1.txt

/*******************************************************************************************************************
To use the following code you need to create a Java based android Project and cross-compile a test C executable on Linux/PC/Mac
and Copy it to Asset Folder of your Android Project.  Instruction on Cross-Compile can be found in
http://www.kandroid.org/ndk/docs/STANDALONE-TOOLCHAIN.html
and
http://www.ikravets.com/computer-life/programming/2014/01/18/an-android-cross-compiling-environment-on-windowsunix-like-systems-using-ndk

The code used to run binary and fetch output from stdout is copied from stackoverflow post -
http://stackoverflow.com/questions/4703131/is-it-possible-to-run-a-native-arm-binary-on-a-non-rooted-android-phone
and
http://gimite.net/en/index.php?Run%20native%20executable%20in%20Android%20App

http://kevinboone.net/android_native.html

********************************************************************************************************************/


package com.example.hellonativecode;

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.widget.TextView;

public class MainActivity extends Activity {
	/** Called when the activity is first created. */
	static final String TAG = "com.example.hellonativecode.MainActivity";
	static final String exeFileName = "hello";
	static String nativePath = "";
	NativeWorker nw;
	TextView tv;
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        /* Create a TextView and set its content.
         */
        copyFile(exeFileName, nativePath, this, true);
        tv = new TextView(this);
        nw = new NativeWorker();
        nw.start();
        setContentView(tv);
    }
    
    private static void copyFile(String assetPath, String localPath, Context context, boolean doCopy) {
        try {
            InputStream in = context.getAssets().open(assetPath);
            //FileOutputStream out = new FileOutputStream(localPath);
            FileOutputStream out = context.openFileOutput(assetPath, Context.MODE_PRIVATE);
            nativePath = context.getFilesDir()+"/"+assetPath;
            int read;
            if (doCopy) {
	            byte[] buffer = new byte[4096];
	            while ((read = in.read(buffer)) > 0) {
	                out.write(buffer, 0, read);
	            }
            }
            out.close();
            in.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    
    class NativeWorker extends Thread {
    	@Override
    	public void run() {
    		final StringBuffer output = new StringBuffer();
    		Process nativeApp = null;
			try {
				nativeApp = Runtime.getRuntime().exec("/system/bin/chmod 777 "+nativePath);
				nativeApp.waitFor();
				Thread.sleep(2000);
				nativeApp = Runtime.getRuntime().exec(nativePath);
			} catch (IOException e) {
				Log.i(TAG, "Binary with name " + nativePath + " not found!!!");
				e.printStackTrace();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
            if (nativeApp != null) {
	              BufferedReader reader = new BufferedReader(new InputStreamReader(nativeApp.getInputStream()));
	              int read;
	              char[] buffer = new char[4096];
	              //output = new StringBuffer();
	              try {
					while ((read = reader.read(buffer)) > 0) {
					      output.append(buffer, 0, read);
					}
		            reader.close();
		            // Waits for the command to finish.
		            nativeApp.waitFor();
	              } catch (IOException e) {
					e.printStackTrace();
	              } catch (InterruptedException e) {
					Log.e(TAG, "Our spawned Process is Interrupted !!");
					e.printStackTrace();
	              }
	              String nativeOutput =  output.toString();
	              Log.e(TAG, "here is the result : "+nativeOutput);
            }
              
    		//run this at the end to signal mainthread our processing is done
    		boolean hdl = new Handler(Looper.getMainLooper(), new Handler.Callback() {
				@Override
				public boolean handleMessage(Message msg) {
					tv.setText(new String(output));
					return true;
				}
			}).sendEmptyMessage(0);
    	}
    }
}