这里列出的许多答案都有内在的问题:

Checking for test-keys is correlated with root access but doesn't necessarily guarantee it "PATH" directories should be derived from the actual "PATH" environment variable instead of being hard coded The existence of the "su" executable doesn't necessarily mean the device has been rooted The "which" executable may or may not be installed, and you should let the system resolve its path if possible Just because the SuperUser app is installed on the device does not mean the device has root access yet

Stericson的RootTools库似乎可以更合理地检查root。它还有很多额外的工具和实用程序，所以我强烈推荐它。然而，并没有解释它是如何专门检查根目录的，而且它可能比大多数应用程序真正需要的要重一些。

我已经创建了几个基于RootTools库的实用程序方法。如果你只是想检查“su”可执行文件是否在设备上，你可以使用以下方法:

public static boolean isRootAvailable(){
    for(String pathDir : System.getenv("PATH").split(":")){
        if(new File(pathDir, "su").exists()) {
            return true;
        }
    }
    return false;
}

这个方法简单地遍历“PATH”环境变量中列出的目录，并检查其中是否存在“su”文件。

为了真正检查root访问权限，必须实际运行“su”命令。如果安装了一个像SuperUser这样的应用程序，那么在这一点上它可能会要求root访问，或者如果它已经被授予/拒绝，吐司可能会显示是否授予/拒绝访问。一个很好的命令是“id”，这样您可以验证用户id实际上是0(根)。

下面是一个示例方法来确定是否授予了根访问权:

public static boolean isRootGiven(){
    if (isRootAvailable()) {
        Process process = null;
        try {
            process = Runtime.getRuntime().exec(new String[]{"su", "-c", "id"});
            BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String output = in.readLine();
            if (output != null && output.toLowerCase().contains("uid=0"))
                return true;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (process != null)
                process.destroy();
        }
    }

    return false;
}

实际测试运行"su"命令是很重要的，因为一些模拟器已经预安装了"su"可执行文件，但只允许某些用户像adb shell一样访问它。

在尝试运行“su”可执行文件之前检查它的存在也是很重要的，因为android已经知道不会正确地处理试图运行缺失命令的进程。随着时间的推移，这些幽灵进程会消耗大量内存。

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;
  }

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");
}

Java级别的根检查不是一个安全的解决方案。如果您的应用程序在root设备上运行有安全问题，那么请使用此解决方案。

凯文的答案是有效的，除非手机也有像RootCloak这样的应用程序。这样的应用程序有一个对Java api的句柄，一旦手机是根的，他们模仿这些api来返回手机不是根的。

我已经写了一个原生级别的代码基于凯文的答案，它甚至与RootCloak !此外，它不会导致任何内存泄漏问题。

#include <string.h>
#include <jni.h>
#include <time.h>
#include <sys/stat.h>
#include <stdio.h>
#include "android_log.h"
#include <errno.h>
#include <unistd.h>
#include <sys/system_properties.h>

JNIEXPORT int JNICALL Java_com_test_RootUtils_checkRootAccessMethod1(
        JNIEnv* env, jobject thiz) {


    //Access function checks whether a particular file can be accessed
    int result = access("/system/app/Superuser.apk",F_OK);

    ANDROID_LOGV( "File Access Result %d\n", result);

    int len;
    char build_tags[PROP_VALUE_MAX]; // PROP_VALUE_MAX from <sys/system_properties.h>.
    len = __system_property_get(ANDROID_OS_BUILD_TAGS, build_tags); // On return, len will equal (int)strlen(model_id).
    if(strcmp(build_tags,"test-keys") == 0){
        ANDROID_LOGV( "Device has test keys\n", build_tags);
        result = 0;
    }
    ANDROID_LOGV( "File Access Result %s\n", build_tags);
    return result;

}

JNIEXPORT int JNICALL Java_com_test_RootUtils_checkRootAccessMethod2(
        JNIEnv* env, jobject thiz) {
    //which command is enabled only after Busy box is installed on a rooted device
    //Outpput of which command is the path to su file. On a non rooted device , we will get a null/ empty path
    //char* cmd = const_cast<char *>"which su";
    FILE* pipe = popen("which su", "r");
    if (!pipe) return -1;
    char buffer[128];
    std::string resultCmd = "";
    while(!feof(pipe)) {
        if(fgets(buffer, 128, pipe) != NULL)
            resultCmd += buffer;
    }
    pclose(pipe);

    const char *cstr = resultCmd.c_str();
    int result = -1;
    if(cstr == NULL || (strlen(cstr) == 0)){
        ANDROID_LOGV( "Result of Which command is Null");
    }else{
        result = 0;
        ANDROID_LOGV( "Result of Which command %s\n", cstr);
        }
    return result;

}

JNIEXPORT int JNICALL Java_com_test_RootUtils_checkRootAccessMethod3(
        JNIEnv* env, jobject thiz) {


    int len;
    char build_tags[PROP_VALUE_MAX]; // PROP_VALUE_MAX from <sys/system_properties.h>.
    int result = -1;
    len = __system_property_get(ANDROID_OS_BUILD_TAGS, build_tags); // On return, len will equal (int)strlen(model_id).
    if(len >0 && strstr(build_tags,"test-keys") != NULL){
        ANDROID_LOGV( "Device has test keys\n", build_tags);
        result = 0;
    }

    return result;

}

在Java代码中，需要创建包装器类RootUtils来进行本机调用

    public boolean checkRooted() {

       if( rootUtils.checkRootAccessMethod3()  == 0 || rootUtils.checkRootAccessMethod1()  == 0 || rootUtils.checkRootAccessMethod2()  == 0 )
           return true;
      return false;
     }

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();
}