code snippet
void takeSnapShot()
{
Process process = null;
try
{
process = Runtime.getRuntime().exec("/system/bin/screencap -p /sdcard/snapshot/test_2.png" );
try
{
process.waitFor();
} catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I am gettin an empty file saved whereas If i use the same command through adb shell, i get my screen captured.
Any help will be appreciatable
Edit: my previous answer was mistaken, any app can use the screen capture command.
It might be a permission issue. Are you sure you have permission to write to sdcard?
Check this post, which covers your topic:
How to run android system app without root permisson?
I solved this by adding the following permission to my Manifest.
<uses-permission
android:name="android.permission.READ_FRAME_BUFFER"
tools:ignore="ProtectedPermissions"/>
NOTE: This is a protected permission, my application is a system app and also signed using the platform key.
Related
after I run any application on my phone, using free version of AIDE -IDE Android, everytime I view LogCat, I get the same message : " run the app to see the log output ".!
Here is the following screenshot :(https://i.stack.imgur.com/uLORU.png)
Is LogCat free on AIDE-IDE Google play app ?
Thank you for your attention.
It's free as far as i know, but you need root access in order for log to work.
Besides: it doesn't work from time to time with root either.
Another option: use following function to log to local file:
public void appendLog(String text)
// https://stackoverflow.com/a/6209739
{
File logFile = new File("sdcard/log.file");
if (!logFile.exists())
{
try
{
logFile.createNewFile();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
try
{
//BufferedWriter for performance, true to set append to file flag
BufferedWriter buf = new BufferedWriter(new FileWriter(logFile, true));
buf.append(text);
buf.newLine();
buf.flush();
buf.close();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
Use it like this:
try{
// your code goes here
}catch (Exception e){
appendLog(e.getMessage());
}
You need to add permission for writing_external_storage in Manifest.
There is no problem with your code. However the problem is with AIDE version your using. Am using the Pro and Logcat is working fine for me
I found this way, as shown below, using Log.getStackTraceString(Exception e), to solve my LogCat View trouble on AIDE-IDE Android. The only remaining question is why there is no display of Log.e (TAG,"Exception ",e) ?
Thank you for your attention.
Code of MainActivity (https://i.stack.imgur.com/Dqfc5.png)
I'm calling C code by JNI in android app.
Every thing is OK in calling, but when I put this code:
FILE* fp = fopen("/storage/sdcard0/input.txt","w+");
if(fp==NULL)
return(*env)->NewStringUTF(env,"n");
else
return(*env)->NewStringUTF(env,"y");
it gets "n". I'm sure that the path is true and I tried this command on my mobile's terminal:
cat /storage/sdcard0/input.txt
and it got me the file's contents.
Edit:
I tried to change the permission of the file by this code but it gave me the same response:
void changePerm()
{
Process chperm;
try {
chperm=Runtime.getRuntime().exec("su");
DataOutputStream os =
new DataOutputStream(chperm.getOutputStream());
os.writeBytes("chmod 777 /storage/sdcard0/input.txt\n");
os.flush();
os.writeBytes("exit\n");
os.flush();
chperm.waitFor();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I also add this permission and no thing changed:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
I take it that the permissions on the file are in fact 0777.
You added android.permission.READ_EXTERNAL_STORAGE, but you try to open for writing
FILE* fp = fopen("/storage/sdcard0/input.txt","w+");
You can get the error by checking for errno and get a message with strerror.
You must either open the file for reading only "r" or add permission for writing WRITE_EXTERNAL_STORAGE
I've sucessfully compiled jNetPcap as a shared library for Android. I have made a simple application using this code: http://jnetpcap.com/examples/classic to test the API.
The problem is that when I call the method findAllDevs and exception is raised with this message: "Can't read list of devices, error issocket: Permission denied"
I cannot understand the reason, since I have made a call in the first part of my program so as to get root permissions for my application and I test my application to a rooted phone. When I run the application, a pop up is raised with this message:"SnifferApp has been granted Superuser permissions" and then the exception occurs.
Any ideas?
Here is a piece of my code:
Process p = Runtime.getRuntime().exec("su");
/*try {
Thread.sleep(10000);
} catch (InterruptedException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} // do nothing for 1000 miliseconds (1 second)
*/
try {
System.loadLibrary(JNETPCAP_LIBRARY_NAME);
}
catch (UnsatisfiedLinkError e) {
System.out.println("Native code library failed to load.\n" + e);
}
/***************************************************************************
* First get a list of devices on this system
**************************************************************************/
int r = Pcap.findAllDevs(alldevs, errbuf);
r = Pcap.findAllDevs(alldevs, errbuf);
if (r == Pcap.NOT_OK || alldevs.isEmpty()) {
tv.append("Can't read list of devices, error is" + errbuf
.toString());
setContentView(tv);
return;
}
As far as I understand, you're creating a new process and getting superuser permission, but your app doesn't have them.
Try adding this permission in your manifest file:
<uses-permission android:name="android.permission.INTERNET" />
as I guess findAllDevs is going to open the network devices on the phone.
I am trying to execute shell command through my code for adding entry in Iptables. The following is my piece of code
private void createShellCommand(String uidValue_param, String interface_param) {
// TODO Auto-generated method stub
StringBuilder cmdScript=new StringBuilder();
script.append("iptables -A OUTPUT " + interface_param + "-m owner --uid-owner " + uidValue_param + "-j REJECT");
writeIptables(cmdScript);
}
private void writeIptables(StringBuilder scriptfile) {
// TODO Auto-generated method stub
String cmd=scriptfile.toString();
if(RootTools.isRootAvailable())
{
Process exec;
try {
exec = Runtime.getRuntime().exec(new String[]{"su","-c"});
final OutputStreamWriter out = new OutputStreamWriter(exec.getOutputStream());
out.write(cmd);
// Terminating the "su" session
out.write("exit\n");
out.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("IPtables updation failed", "Iptable write failed"+e);
}
}
else
{
Log.e("Root Access denied", "Access Denied");
}
}
Here there are two methods i.e, createshellCommand() for building the shell command and writeIptables() for updating the iptables. But whenever I run the program logcat is displaying the following warning
"W 19913 su request rejected (0->0 /system/bin/sh)"
But I can manually add the entry through command prompt and its adding to the iptables but by using the above code its not updating. My phone is rooted and I am using android 2.3.4 with linux kernel 2.6.29. And I am using external library "Roottools" for checking the root access.
Please help me to rectify the error.
This Works:
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
execute_reboot();
}
void execute_reboot()
{
Process reboot;
try {
reboot=Runtime.getRuntime().exec("su");
DataOutputStream os =
new DataOutputStream(reboot.getOutputStream());
os.writeBytes("reboot\n");
os.flush();
os.writeBytes("exit\n");
os.flush();
reboot.waitFor();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
This Code Works fine. There are couple of small mistakes in your program. Try the one i pasted. Its working charm. All the best. I kept it as simple as possible so that it is easy to understand. You can still use arrays and other stuff to fancy your coding.
And yaa the same one also works for chmod command where you need to pass more than one argument.
For this Just replace
"os.writeBytes("reboot\n");"
with
"chmod 777 /dev/video0\n"(or any other system file).
Thanks. LEt me know if there is something tat i can do.
public static void rebootNow() {
Log.d(TAG, "Rebooting");
try {
#SuppressWarnings("unused")
Process proc = Runtime.getRuntime().exec(
new String[] { "su", "-c", "reboot" });
} catch (Exception ex) {
Log.d(TAG, "Rebooting failed (Terminal Error)");
}
}
This one is a little more compact
You can add "proc.waitFor();" after the Process proc... line to get rid of the unused warning, but rebooting your device takes a few seconds time and if you want to disable some features during the few seconds in your UI-thread, I think its better to not wait for the process to end.
Trying using the iptables command (with sudo and without), rather than just clobbering the iptables config file.
I've hit a bit of a wall. Any help would be appreciated. I have an app that I want to use DexClassLoader to load another apk file.
Here is my code:
DexClassLoader dLoader = new DexClassLoader("/sdcard/download/test.apk","/sdcard/download",null,ClassLoader.getSystemClassLoader().getParent());
Class calledClass = dLoader.loadClass("com.test.classname");
Intent it=new Intent(this, calledClass);
it.setClassName("com.test", "com.test.classname");
startActivity(it);
Now I had already installed test.apk so when I ran the above code it
worked fine and launched the application. However I want to be able to
run this without test.apk being installed already (as that would
defeat the entire point of the application) . So I uninstalled it and
when I ran the my app again I get this error:
android.content.ActivityNotFoundException: Unable to find explicit
activity class {com.test/com.test.classname}; have you declared this
activity in your AndroidManifest.xml.
So I'm a bit stumped here. This activity is declared in the Manifest
of the apk I am trying to run. I can't declare it in my applications
Manifest. Any ideas?
Thanks,
Craig
Try using Android's PathClassLoader:
String packagePath = "com.mypackage";
String classPath = "com.mypackage.ExternalClass";
String apkName = null;
try {
apkName = getPackageManager().getApplicationInfo(packagePath,0).sourceDir;
} catch (PackageManager.NameNotFoundException e) {
// catch this
}
// add path to apk that contains classes you wish to load
String extraApkPath = apkName + ":/path/to/extraLib.apk"
PathClassLoader pathClassLoader = new dalvik.system.PathClassLoader(
apkName,
ClassLoader.getSystemClassLoader());
try {
Class<?> handler = Class.forName(classPath, true, pathClassLoader);
} catch (ClassNotFoundException e) {
// catch this
}
Although the question is old, I will answer because I struggled a bit to find a clear answer for your same question for myself. First, I would like to highlight that a clear requirement in your question is to load a class from an .apk that is not already installed on the device. Therefore, calling the package manager using getPackageManager() and providing it with the package path will clearly lead to NameNotFoundException because the .apk that has the package is not installed on the device.
So, the way to go about loading classes from an .apk file that is not installed on the device (i.e. you only have the .apk stored in a directory on your SDCARD) is by using DexClassLoader as follows:
1- Make sure you have the .apk file in a directory on your SDCARD. I've mine Offloadme.apk in the Download folder on my SDCARD.
2- Add read permission in your AndroidManifest.xml to allow your app to read from the manifest.
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
3- Use the following definitions to define the path of the .apk, the class name inside the apk, and method name in that class that you would like to invoke:
final String apkFile =Environment.getExternalStorageDirectory().getAbsolutePath()+"/Download/Offloadme.apk";
String className = "com.khaledalanezi.offloadme.SimpleCalculator";
String methodToInvoke = "add";
4- Use the DexClassLoader to load the .apk and call the add method in the SimpleCalculator class using reflection as follows:
final File optimizedDexOutputPath = getDir("outdex", 0);
DexClassLoader dLoader = new DexClassLoader(apkFile,optimizedDexOutputPath.getAbsolutePath(),
null,ClassLoader.getSystemClassLoader().getParent());
try {
Class<?> loadedClass = dLoader.loadClass(className);
Object obj = (Object)loadedClass.newInstance();
int x =5;
int y=6;
Method m = loadedClass.getMethod(methodToInvoke, int.class, int.class);
int z = (Integer) m.invoke(obj, y, x);
System.out.println("The sum of "+x+" and "+"y="+z);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Note that in my simple example, I added two numbers using the add method available in the SimpleCalculator class loaded from the Offloadme.apk file stored on my SDCARD and I was able to print the correct answer which is 11.
You can't do that. Even if you're able to access classes from external file, Android still does not know them. And you don't run activities directly, but by requesting Android to run them, so they have to be registered/installed into system.