int count = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button start = (Button) findViewById(R.id.start);
start.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
String[] cmd = new String[] { "logcat", "-f",Environment.getExternalStorageDirectory()+"/log.txt", "-v", "time" };
Runtime.getRuntime().exec(cmd);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
thread.start();
}
});
Button stop = (Button) findViewById(R.id.stop);
stop.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
Runtime.getRuntime().exec("logcat -d");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
Button addLog = (Button) findViewById(R.id.addLog);
addLog.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.e("logTag", Integer.toString(count));
count ++ ;
}
});
}
I want to start saving my app's log using start button and stop it using stop.
The addLog button is used to see if more lines are being added to log.txt file.
The start button works properly but the problem is it never ends with stop.
Even after pressing stop, when I press addLog button and check the log.txt
file, I see last lines have been added.
What is my fault ?
I need to start the stream, close this activity and take a tour in other activities then come back and shut the logging machine down.
Yes you can achieve that by saving the Process in a variable that is returned by the Runtime's exec() method and call destroy() on that variable.
public abstract void destroy ()
Terminates this process and closes any associated
streams.
Let's record the Process as a global variable;
private Process p;
and when executing it
p = Runtime.getRuntime().exec(cmd);
and this how it's stopped.
void stopProcess() {
if (p != null) {
p.destroy();
} else {
Log.d(TAG, "stopProcess: p==null");
}
}
Just use #hegazy method and save reference to process in your Application class. Don't forget to register it in your manifest. Hope you've got my idea.
Something like that:
((App)getApplicationContext).process = Runtime.getRuntime().exec(cmd);
and than take this when you need it:
((App)getApplicationContext).process.exec("logcat -d");
Related
I'm new in stackoverflow.
I created a simple bluetooth app to controll a relay board.
The Relay is "on" for 1s after clicking the a button.
It works so far but if I click the button during the 1s the relay gets "on" for another 1s.
So I want to disable the button while the relay is "on". I used .postDelayed().
This works as well, but it is not possible to generate the outputStream to clear the relay in the .postDelayed() routine.
Does anybody have an idea for me?
regards
Joe
// Rel1 btn click
mRel1Btn.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
mRel1Btn.setEnabled(false);
mRel1Btn.setClickable(false);
if (mBlueAdapter.isEnabled()) {
try {
OutputStream mOutputStream = mBtSocket.getOutputStream();
mOutputStream.write(RELAY_ON);
new Handler().postDelayed(new Runnable()
{
public void run()
{
mRel1Btn.setEnabled(true);
mRel1Btn.setClickable(true);
mOutputStream.write(RELAY_OFF); // sending bytes to serial COM (BT)
}
}, 1000 //Specific time in milliseconds
);
} catch (IOException e) {
e.printStackTrace();
}
}
}
});
Following error occured
error: unreported exception IOException; must be caught or declared to be thrown
mOutputStream.write(RELAY_OFF);
(marker on opening brace)
Solved:
I created a subroutine "sendMessage(message)" and called this subroutine out of my listener.
// Rel1 btn click
mRel1Btn.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
if (mBlueAdapter.isEnabled()) {
sendMessage(RELAY1_JDY30_ON);
mRel1Btn.setEnabled(false);
mRel1Btn.setClickable(false);
new Handler().postDelayed(new Runnable()
{
public void run()
{
sendMessage(RELAY1_JDY30_OFF);
mRel1Btn.setEnabled(true);
mRel1Btn.setClickable(true);
}
}, 1000 //Specific time in milliseconds
);
}
}
});
.
.
.
private void sendMessage(byte[] message) {
OutputStream mOutputStream;
try {
mOutputStream = mBtSocket.getOutputStream();
mOutputStream.write(message);
} catch (IOException e) {
e.printStackTrace();
}
}
i am trying to display a Toast on the screen and when Toast fades off then move to the next question. I have tried with Thread but cannot seem to manage.
My code:
next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (getUserSelection()){
position = position + 3;
if (position < questionsArray.size()) {
curName = questionsArray.get(position).getName();
curArray = questionsArray.get(position).getAnswers();
curIscorrect = questionsArray.get(position).getIscorrect();
setupQuestionView(curName, curArray, curIscorrect);
} else {
StringGenerator.showToast(QuestionsActivity.this, "Your score : " + score + "/" + (questionsArray.size() / 3));
}
}else {
StringGenerator.showToast(QuestionsActivity.this, getString(R.string.noanswerselected));
}
}
});
and the getUserSelectionMethod:
private boolean getUserSelection() {
correct = (RadioButton)findViewById(group.getCheckedRadioButtonId());
if (correct == null){
return false;
}else {
correctAnswerText = correct.getText().toString();
if (map.get(correctAnswerText).equals(Constants.CORRECTANSWER)) {
score++;
setCorrectMessage();
return true;
} else {
setWrongMessage();
return true;
}
}
}
private void setCorrectMessage() {
correctToast = new Toast(QuestionsActivity.this);
correctToastView = getLayoutInflater().inflate(R.layout.correct, (ViewGroup) findViewById(R.id.correctRootLayout));
correctText = (TextView)correctToastView.findViewById(R.id.correctTextView);
correctText.setText(getString(R.string.correctAnswer));
correctToast.setDuration(Toast.LENGTH_SHORT);
correctToast.setView(correctToastView);
correctToast.show();
correctThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
correctToast.cancel();
}
});
correctThread.start();
}
private void setWrongMessage() {
wrongToast = new Toast(QuestionsActivity.this);
wrongToastView = getLayoutInflater().inflate(R.layout.wrong, (ViewGroup) findViewById(R.id.wrongRootLayout));
wrongText = (TextView)wrongToastView.findViewById(R.id.wrongTextView);
wrongText.setText(getString(R.string.wrongAnswer));
wrongToast.setDuration(Toast.LENGTH_SHORT);
wrongToast.setView(wrongToastView);
wrongToast.show();
wrongThread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
wrongToast.cancel();
}
});
wrongThread.start();
}
Any suggestion on how to do this?
You can determine the toast visibility:
toast.getView().getWindowToken()
If the result is null, than your toast isn't visible anymore, and than you can run any code you want.
as stated in this answer you can start a thread that waits the duration of the Toast:
Thread thread = new Thread(){
#Override
public void run() {
try {
Thread.sleep(3500); // 3.5seconds!
// Do the stuff you want to be done after the Toast disappeared
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Toast.LENGTH_SHORT and Toast.LENGTH_LONG are only flags so you have to either hard code the duration or keep them in a constant. The durations are 3.5s (long) and 2s (short).
If you want to manipulate some of your views, you cannot do this in another thread than the "main" UI thread. So you have to implement a kind of callback/polling mechanism to get notified when the SleepThread has finished.
Check this answer to read about a couple of ways to do this. Probably the easiest of them to understand and implement is this:
After you started your Thread you can check if it is still alive and running by calling thread.isAlive(). In this way you can do a while loop that runs while the thread is running:
// start your thread
while(thread.isAlive()){}
// continue the work. The other thread has finished.
Please note that this is NOT the most elegant way to do this! Check the other possibilities in the answer I've mentioned above for more elegant solutions (especially the last one with the listeners is very interesting and worth reading!)
That's because the Thread class is purely executed in the background and you need to manipulate the view in the Main thread. To solve your issue just replace the Thread with AsynTask.
AsyncTask<Void,Void,Void> a = new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
correctToast.cancel();
}
};
a.execute();
If you look at my code you can see my onPostExecute, this method is called in the Main Thread.
My Error was because i was trying to acess UI Elements through another Thread so modifying the code like this:
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
try {
Thread.sleep(500);
QuestionsActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
moveToNextQuestion();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
thread.start();
did the trick. I hope my answer helps someone!!!
Can I use a thread for increment a counter and shows it in a frame of Android activity.
Public class MainActivity extendsActivity {
TextView counter;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
counter = (TextView) findViewById(R.id.TV_counter);
Thread t = new Thread() {
public void run() {
runOnUiThread(new Runnable() {
public void run() {
for (int i = 0; i < 5; i++) {
try {
counter.setText("" + i);
System.out.println("Value of i= " + i);
sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
}
};
t.start();
}
}
I wrote this code, but it run properly in console, but the text view displays i=4 in the terminal, I modified the time to sleep(3000) and the problem persists.
First you don't ever want to put sleep in UI Thread that can lead to unresponsive user interface and that is never good. You should use it just to update your graphics. Try replacing your code with this
Thread t = new Thread() {
public void run() {
for (int i = 0; i < 5; i++) {
try {
final int a = i;
runOnUiThread(new Runnable() {
public void run() {
counter.setText("" + a);
}
});
System.out.println("Value of i= " + i);
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
};
t.start();
You are going to notice that sleep and for loop is outside UIThread and in your first thread, so basically all of your math is done outside and you just display the results.
This is just a correction of your code and suggestion for further thinking
EDIT: And for you to better understand why your code is not working, you set some value on your TextView, and immediately after you set UIThread to sleep, UIThread blocks instead of giving it time to finish updating graphics, after he finish sleep you set new value, and he never got to update previous one so in the end you see just the last one.
Hope this helps and enjoy your work.
you can use a CountDownTimer, and update your UI in the onTick() method ( this method is executed on the UI Thread):
int i=0;
CountDownTimer timer = new CountDownTimer(5000,1000) {
#Override
public void onTick(long millisUntilFinished) {
// this method will be executed every second ( 1000 ms : the second parameter in the CountDownTimer constructor)
i++;
txt.setText(i);
}
#Override
public void onFinish() {
// TODO Auto-generated method stub
}
};
timer.start();
How create a button which pause the thread which is inside the loop and another button which
resumes.
Runnable myRun = new Runnable(){
public void run(){
for(int j =0 ;j<=words.length;j++){
synchronized(this){
try {
wait(sleepTime);
bt.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}});
bt2.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
notify();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
} }
runOnUiThread(new Runnable(){
public void run(){
try {
et.setText(words[i]);
i++;
} catch (Exception e) {
e.printStackTrace();
}
}});
}}};
doing some stuff say words.lenght=1000 times
then suppose user want to take break in between
click pause button with id = bt this button pauses thread until and user
clicks resume with id= bt1
Below is a hint , i think you can use for your problem. Its copied from the link i pasted at end.
A wait can be "woken up" by another process calling notify on the monitor which is being waited on whereas a sleep cannot. Also a wait (and notify) must happen in a block synchronized on the monitor object whereas sleep does not:
Object mon = ...;
synchronized (mon) {
mon.wait();
}
At this point the currently executing thread waits and releases the monitor. Another thread may do
synchronized (mon) { mon.notify(); }(On the same mon object) and the first thread (assuming it is the only thread waiting on the monitor) will wake up.
Check Difference between wait() and sleep()
You do it like this:
How to indefinitely pause a thread in Java and later resume it?
Only you call the suspend() and other methods from your buttons' OnClickListeners
I'm not the best programmer, actually, I'm pretty bad :(
I need help with something thats driving my crazy. basically I have a tcpdump process, I want to extract the output and put it into a textview which is updated every few milliseconds, I've tried everything and just cant get it to work.
I don't get any errors and it seems to work in the background, but only displays chunks of text only after I go to the homescreen and return back into the app. however, it doesnt constantly update the textview, and sometimes hangs and crashes.
I've created a simple handler which can update the textview with plain text without problems, but then i faced major problems getting it to read the process.
Begin button
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.capture);
this.LiveTraffic = (TextView) findViewById(R.id.LiveTraffic);
this.CaptureText = (TextView) findViewById(R.id.CaptureText);
((TextView) findViewById(R.id.ipv4)).setText(getLocalIpv4Address());
((TextView) findViewById(R.id.ipv6)).setText(getLocalIpv6Address());
//Begin button
final Button startButton = (Button) findViewById(R.id.start);
startButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Toast.makeText(getApplicationContext(), "Now Capturing Packets", Toast.LENGTH_LONG).show();
try {
process = Runtime.getRuntime().exec("su");
DataOutputStream os = new DataOutputStream(process.getOutputStream());
os.writeBytes("/data/local/tcpdump -q\n");
os.flush();
os.writeBytes("exit\n");
os.flush();
os.close();
inputStream = new DataInputStream(process.getInputStream());
Thread.sleep(1000);
Process process2 = Runtime.getRuntime().exec("ps tcpdump");
DataInputStream in = new DataInputStream(process2.getInputStream());
String temp = in.readLine();
temp = in.readLine();
temp = temp.replaceAll("^root *([0-9]*).*", "$1");
pid = Integer.parseInt(temp);
Log.e("MyTemp", "" + pid);
process2.destroy();
CaptureActivity.this.thisActivity.CaptureText.setText("Active");
} catch (Exception e) {
}
ListenThread thread = new ListenThread(new BufferedReader(new InputStreamReader(inputStream)));
thread.start();
}
});
}
ListenThread class
public class ListenThread extends Thread {
public ListenThread(BufferedReader reader) {
this.reader = reader;
}
private BufferedReader reader = null;
#Override
public void run() {
reader = new BufferedReader(new InputStreamReader(inputStream));
while (true) {
try {
CaptureActivity.this.thisActivity.CaptureText.setText("exec");
int a = 1;
String received = reader.readLine();
while (a == 1) {
CaptureActivity.this.thisActivity.LiveTraffic.append(received);
CaptureActivity.this.thisActivity.LiveTraffic.append("\n");
received = reader.readLine();
CaptureActivity.this.thisActivity.CaptureText.setText("in loop");
}
CaptureActivity.this.thisActivity.CaptureText.setText("out loop");
} catch (Exception e) {
Log.e("FSE", "", e);
}
}
}
}
I am not an android expert but I notice that:
you are running I/O operations in the UI thread - that will freeze your GUI until the I/O operation finishes ==> run them in a separate thread.
you update the UI from outside the UI thread in ListenThread, which can lead to unexpected results
You can read more about it in this tutorial (make sure you read the 2 examples as the first one is broken (on purpose)).
EDIT
In conclusion you should have something like this in your first piece of code:
startButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Toast.makeText(getApplicationContext(), "Now Capturing Packets", Toast.LENGTH_LONG).show();
new Thread(new Runnable() {
public void run() {
try {
process = Runtime.getRuntime().exec("su");
...
CaptureActivity.this.runOnUiThread(new Runnable() {
public void run() {
CaptureActivity.this.thisActivity.CaptureText.setText("Active");
}
});
} catch (Exception e) {
}
ListenThread thread = new ListenThread(new BufferedReader(new InputStreamReader(inputStream)));
thread.start();
}
}).start();
}
});
and in the second:
while (true) {
try {
CaptureActivity.this.runOnUiThread(new Runnable() {
public void run() {
CaptureActivity.this.thisActivity.CaptureText.setText("exec");
}
});
int a = 1;
String received = reader.readLine();
while (a == 1) {
CaptureActivity.this.runOnUiThread(new Runnable() {
public void run() {
CaptureActivity.this.thisActivity.LiveTraffic.append(received);
CaptureActivity.this.thisActivity.LiveTraffic.append("\n");
CaptureActivity.this.thisActivity.CaptureText.setText("in loop");
}
});
received = reader.readLine();
}
CaptureActivity.this.runOnUiThread(new Runnable() {
public void run() {
CaptureActivity.this.thisActivity.CaptureText.setText("out loop");
}
});
} catch (Exception e) {
Log.e("FSE", "", e);
}
}
That should solve the specific UI interaction issue. But there are other logic problems in your code which go beyond this question (for example the fact that you never test if you have reached the end of the file you are reading, the fact that while(a==1) is an infinite loop because you never change the value of a etc.).