I think there is something that I'm just not yet getting about how these Views are to be coded. This is the third time I have had to come and post a question rearding them in the last 3 days! :S
Anyway, my problem is as follows.
edit: This is the code inside a method that gets executed on a button press: (Points of importance are noted)
>> setContentView(R.layout.stop);
>> timer = (TextView) findViewById(R.id.timer2);
GPSMain.button = (Button) findViewById(R.id.stopbutton);
startService(new Intent(context, Timer.class));
}
This is the Timer class that is executed in the "startService" call: (Again points of importance are noted)
public class Timer extends Service {
static int totalSeconds = 0;
private int hour = 0;
private int min = 0;
private int sec = 0;
String mTimeFormat = "%02d:%02d:%02d";
final private Handler mHandler = new Handler();
static String timeTaken;
Context context = this;
Runnable mUpdateTime = new Runnable() {
public void run() { updateTimeView(); }
};
@Override
public void onCreate() {
Toast.makeText(context, "Timer Started", Toast.LENGTH_LONG).show();
mHandler.postDelayed(mUpdateTime, 1000);
}
public void updateTimeView() {
totalSeconds += 1;
sec += 1;
if(sec >= 60) {
sec = 0;
min += 1;
if (min >= 60) {
min = 0;
hour += 1;
}
}
>> timeTaken = String.format(mTimeFormat, hour, min, sec);
>> GPSMain.timer.setText("Time Taken: "+timeTaken);
mHandler.postDelayed(mUpdateTime, 1000);
}
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
}
The logcat returns a NullPointerException on the following line of code:
GPSMain.timer.setText("Time Taken: "+timeTaken);
If I remove that line of code the code executes properly*, well I say properly because it executes all the way to the end of the application code, but the reason that I want to print the timer to the screen as it is counting is because I need to make sure that it is functioning correctly.
*not only does it run properly but it displays the timer text view with it's default defined string from the xml. It's only when I try to update it from the java that it crashes.
Here is the full xml file that the code is referencing at this point:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button
android:id="@+id/stopbutton"
android:layout_width="100px"
android:layout_height="100px"
android:text="Stop"
android:layout_centerInParent="true"
/>
<TextView
android:id="@+id/timer2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Time Taken: unknown"
android:layout_below="@+id/timer"
/>
</RelativeLayout>
UPDATE!
The MyTimer Class:
@SuppressWarnings("unchecked")
public class MyTimer extends AsyncTask {
Timer _timerTask = new Timer();
static int totalSeconds = 0, hour = 0, min = 0, sec = 0;
static String mTimeFormat = "%02d:%02d:%02d";
static String timeTakenString;
@Override
protected Object doInBackground(Object... params) {
TimerTask timer = new TimerTask() {
@Override
public void run() {
totalSeconds += 1;
sec += 1;
if(sec >= 60) {
sec = 0;
min += 1;
if (min >= 60) {
min = 0;
hour += 1;
}
}
timeTakenString = String.format(mTimeFormat, hour, min, sec);
GPSMain.timer.setText("Time Taken: "+GPSMain.timeTaken);
}
};
(_timerTask).scheduleAtFixedRate(timer,1000,1000);
return null;
}
}
The method to start the timer thread:
void startService(){
setContentView(R.layout.stop);
timer = (TextView) findViewById(R.id.timer2);
GPSMain.button = (Button) findViewById(R.id.stopbutton);
new MyTimer().execute();
}
You can use TimerTask instead of Service . Here is the code ..
TimerTask timer = new TimerTask() {
@Override
public void run() {
// Here you can update your UI
}
}
Timer _timerTask = new Timer();
_timerTask.scheduleAtFixedRate(timer,60000,60000);