android在apk中获取root权限，并执行下令

android在apk中获取root权限，并执行命令

工程代码：http://download.csdn.net/detail/victoryckl/4610617

    在apk中，有时候需要root权限，例如通过apk更新系统库等system的文件等，避免升级固件，或者在apk中需要直接访问某些设备等。下面是在apk中获取root权限的方法，前提是设备已经root过了。

   关键点在于下面这句，通过执行su产生一个具有root权限的进程：

Process p = Runtime.getRuntime().exec("su");

然后，在向这个进程的写入要执行的命令，即可达到以root权限执行命令：

dos = new DataOutputStream(p.getOutputStream());

dos.writeBytes(cmd + "\n");

dos.flush();

或者用下面的方式：

Runtime.getRuntime().exec(new String[]{"/system/bin/su","-c", cmd});

经过测试，以root权限执行命令，只在真机上测试成功，在模拟器上没有成功过。

第一次运行时，会出现请求root权限的界面，选中记住，并允许：

测试程序界面，如果已经root，界面中可以显示出/system分区对应的设备节点：

主要文件：RootCmd.java

package org.ckl.root;import java.io.DataInputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import android.util.Log;public class SystemPartition {private static final String TAG = "SystemMount";private static String TMP_PATH = "/sdcard/mount.txt";private static String mMountPiont = null;private static boolean mWriteable = false;private SystemPartition() {Log.i(TAG, "new SystemMount()");}private static class SystemPartitionHolder {private static SystemPartition instance = new SystemPartition();}public SystemPartition getInstance() {return SystemPartitionHolder.instance;}public static String getSystemMountPiont() {DataInputStream dis = null;if (mMountPiont == null) { try {RootCmd.execRootCmd("mount > " + TMP_PATH);//Runtime.getRuntime().exec("mount > " + TMP_PATH);dis = new DataInputStream(new FileInputStream(TMP_PATH));String line = null;int index = -1;while ( (line = dis.readLine()) != null ) {index = line.indexOf(" /system ");if (index > 0) {mMountPiont = line.substring(0, index);if (line.indexOf(" rw") > 0) {mWriteable = true;Log.i(TAG, "/system is writeable !");} else {mWriteable = false;Log.i(TAG, "/system is readonly !");}break;}}} catch (Exception e) {e.printStackTrace();} finally {if (dis != null) {try {dis.close();} catch (IOException e1) {e1.printStackTrace();}dis = null;}File f = new File(TMP_PATH);if (f.exists()) {f.delete();}}}if (mMountPiont != null) {Log.i(TAG, "/system mount piont: " + mMountPiont);} else {Log.i(TAG, "get /system mount piont failed !!!");}return mMountPiont;}public static boolean isWriteable() {mMountPiont = null;getSystemMountPiont();return mWriteable;}public static void remountSystem(boolean writeable) {String cmd = null;getSystemMountPiont();if (mMountPiont != null && RootCmd.haveRoot()) {if (writeable) {cmd = "mount -o remount,rw " + mMountPiont + " /system";} else {cmd = "mount -o remount,ro " + mMountPiont + " /system";}RootCmd.execRootCmdSilent(cmd);isWriteable();}}}