關于判斷手機是否已經root的方法。如果app有一些特殊功能需要root權限，則需要判斷是否root。比如一些市場下載完app后自動安裝。

方法1：

/**
* @author Kevin Kowalewski
*
*/
public class Root {

private static String LOG_TAG = Root.class.getName();

public boolean isDeviceRooted() {
if (checkRootMethod1()){return true;}
if (checkRootMethod2()){return true;}
if (checkRootMethod3()){return true;}
return false;
}

public boolean checkRootMethod1(){
String buildTags = android.os.Build.TAGS;

if (buildTags != null && buildTags.contains(“test-keys”)) {
return true;
}
return false;
}

public boolean checkRootMethod2(){
try {
File file = new File(“/system/app/Superuser.apk”);
if (file.exists()) {
return true;
}
} catch (Exception e) { }

return false;
}

public boolean checkRootMethod3() {
if (new ExecShell().executeCommand(SHELL_CMD.check_su_binary) != null){
return true;
}else{
return false;
}
}
}
/**
* @author Kevin Kowalewski
*
*/
public class ExecShell {

private static String LOG_TAG = ExecShell.class.getName();

public static enum SHELL_CMD {
check_su_binary(new String[] {“/system/xbin/which”,”su”}),
;

String[] command;

SHELL_CMD(String[] command){
this.command = command;
}
}

public ArrayList<String> executeCommand(SHELL_CMD shellCmd){
String line = null;
ArrayList<String> fullResponse = new ArrayList<String>();
Process localProcess = null;

try {
localProcess = Runtime.getRuntime().exec(shellCmd.command);
} catch (Exception e) {
return null;
//e.printStackTrace();
}

BufferedWriter out = new BufferedWriter(new OutputStreamWriter(localProcess.getOutputStream()));
BufferedReader in = new BufferedReader(new InputStreamReader(localProcess.getInputStream()));

try {
while ((line = in.readLine()) != null) {
Log.d(LOG_TAG, “–> Line received: ” + line);
fullResponse.add(line);
}
} catch (Exception e) {
e.printStackTrace();
}

Log.d(LOG_TAG, “–> Full response was: ” + fullResponse);

return fullResponse;
}

}

代碼來自stackoverflow，向作者致敬。

方法2：

The RootTools library offers simple methods to check for root:

一個開源項目：http://code.google.com/p/roottools/

RootTools.isRootAvailable()判斷是否root

RootTools.isAccessGiven()返回true那么手機已經root并且app也被授予root權限。

String commandToExecute = “su”;
executeShellCommand(commandToExecute);
private boolean executeShellCommand(String command){
Process process = null;
try{
process = Runtime.getRuntime().exec(command);
return true;
} catch (Exception e) {
return false;
} finally{
if(process != null){
try{
process.destroy();
}catch (Exception e) {
}
}
}
}

另外：據那片帖子的一個回貼人說使用會引起非常嚴重的性能問題，將手機系統拖的非常慢，當應用多次啟動后會創建出很多個僵死的進程耗用內存。

參考 http://stackoverflow.com/questions/1101380/determine-if-running-on-a-rooted-device