你可以通过以下代码来做到这一点:

public boolean getRootInfo() {
    if (checkRootFiles() || checkTags()) {
        return true;
    }
    return false;
}

private boolean checkRootFiles() {
    boolean root = false;
    String[] paths = {"/system/app/Superuser.apk", "/sbin/su", "/system/bin/su", "/system/xbin/su", "/data/local/xbin/su", "/data/local/bin/su", "/system/sd/xbin/su",
            "/system/bin/failsafe/su", "/data/local/su", "/su/bin/su"};
    for (String path : paths) {
        root = new File(path).exists();
        if (root)
            break;
    }
    return root;
}

private boolean checkTags() {
    String tag = Build.TAGS;
    return tag != null && tag.trim().contains("test-keys");
}

你也可以检查RootBeer这个库。

使用c++和ndk是最好的方法来检测根，即使用户使用的应用程序隐藏了他的根，如RootCloak。我用RootCloak测试了这段代码，即使用户试图隐藏它，我也能够检测到根。 所以你的cpp文件是这样的:

#include <jni.h>
#include <string>


/**
 *
 * function that checks for the su binary files and operates even if 
 * root cloak is installed
 * @return integer 1: device is rooted, 0: device is not 
 *rooted
*/
extern "C"
JNIEXPORT int JNICALL


Java_com_example_user_root_1native_rootFunction(JNIEnv *env,jobject thiz){
const char *paths[] ={"/system/app/Superuser.apk", "/sbin/su", "/system/bin/su",
                      "/system/xbin/su", "/data/local/xbin/su", "/data/local/bin/su", "/system/sd/xbin/su",
                      "/system/bin/failsafe/su", "/data/local/su", "/su/bin/su"};

int counter =0;
while (counter<9){
    if(FILE *file = fopen(paths[counter],"r")){
        fclose(file);
        return 1;
    }
    counter++;
}
return 0;
}

您将从java代码中调用该函数，如下所示

public class Root_detect {



   /**
    *
    * function that calls a native function to check if the device is 
    *rooted or not
    * @return boolean: true if the device is rooted, false if the 
    *device is not rooted
   */
   public boolean check_rooted(){

        int checker = rootFunction();

        if(checker==1){
           return true;
        }else {
           return false;
        }
   }
   static {
    System.loadLibrary("cpp-root-lib");//name of your cpp file
   }

   public native int rootFunction();
}

http://code.google.com/p/roottools/

如果你不想使用jar文件，请使用下面的代码:

public static boolean findBinary(String binaryName) {
        boolean found = false;
        if (!found) {
            String[] places = { "/sbin/", "/system/bin/", "/system/xbin/",
                    "/data/local/xbin/", "/data/local/bin/",
                    "/system/sd/xbin/", "/system/bin/failsafe/", "/data/local/" };
            for (String where : places) {
                if (new File(where + binaryName).exists()) {
                    found = true;

                    break;
                }
            }
        }
        return found;
    }

程序将尝试查找su文件夹:

private static boolean isRooted() {
        return findBinary("su");
    }

例子:

if (isRooted()) {
   textView.setText("Device Rooted");

} else {
   textView.setText("Device Unrooted");
}

忘记所有那些检测根应用程序和子二进制文件。检查根守护进程。这可以从终端完成，你可以在应用程序中运行终端命令。试试这一行。

if [ ! "$(/system/bin/ps -A | grep -v grep | grep -c daemonsu)" = "0" ]; then echo "device is rooted"; else echo "device is not rooted"; fi

您也不需要root权限来实现这一点。

编辑:现在使用这种方法更好的检测!

if [ $(ps -A | grep -e ^shell -e ^root | grep -v "\[" | tr -s ' ' | cut -d ' ' -f 9 | grep -c su) ] || [ $(which su) ]; then echo 'rooted'; else echo 'not rooted'; fi

RootTools库提供了简单的方法来检查根:

RootTools.isRootAvailable()

参考

以下是我的代码，基于这里的一些答案:

 /**
   * Checks if the phone is rooted.
   * 
   * @return <code>true</code> if the phone is rooted, <code>false</code>
   * otherwise.
   */
  public static boolean isPhoneRooted() {

    // get from build info
    String buildTags = android.os.Build.TAGS;
    if (buildTags != null && buildTags.contains("test-keys")) {
      return true;
    }

    // check if /system/app/Superuser.apk is present
    try {
      File file = new File("/system/app/Superuser.apk");
      if (file.exists()) {
        return true;
      }
    } catch (Throwable e1) {
      // ignore
    }

    return false;
  }