I have trouble using thread.join in my code below. It should wait for the thread to finish before executing the codes after it, right? It was behaving differently on different occasions.
I have three cases to check if my code goes well
App is used for the first time - works as expected but the loading page don't appear while downloading
App is used the second time (db is up to date) - works okay
App is used the third time (db is outdated, must update) - won't update, screen blacks out, then crashes
I think I have problems with this code on onCreate method:
dropOldSchedule();
dropThread.join();
triggerDownload();
Based on the logs, the code works until before this part... What can be the problem?
MainActivity.java
public class MainActivity extends Activity {
final static int INDEX_ACCTTYPE = 0;
final static int INDEX_ECN = 1;
final static int INDEX_TLN = 2;
final static int INDEX_SIN = 3;
final static int INDEX_MOBILE = 4;
final static int INDEX_CITY = 5;
final static int INDEX_START_DATE = 6;
final static int INDEX_START_TIME = 7;
final static int INDEX_END_DATE = 8;
final static int INDEX_END_TIME = 9;
final static int INDEX_REASON = 10;
final static int INDEX_DETAILS = 11;
DatabaseHandler db;
String str;
ProgressDialog pd;
TextView homeText1, homeText2, homeText3, homeText4;
final private String csvFile = "http://www.meralco.com.ph/pdf/pms/pms_test.csv";
final private String uploadDateFile = "http://www.meralco.com.ph/pdf/pms/UploadDate_test.txt";
Thread dropThread = new Thread(new Runnable() {
public void run() {
db = new DatabaseHandler(MainActivity.this);
db.dropOldSchedule();
runOnUiThread(new Runnable() {
public void run() {
while (!pd.isShowing());
db.close();
pd.dismiss();
}
});
}
});
Thread getUploadDateThread = new Thread(new Runnable() {
public void run() {
try {
URL myURL = new URL(uploadDateFile);
BufferedReader so = new BufferedReader(new InputStreamReader(myURL.openStream()));
while (true) {
String output = so.readLine();
if (output != null) {
str = output;
}
else {
break;
}
}
so.close();
}
catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
runOnUiThread(new Runnable() {
public void run() {
while (!pd.isShowing());
pd.dismiss();
}
});
}
});
Thread downloadThread = new Thread(new Runnable() {
public void run() {
db = new DatabaseHandler(MainActivity.this);
db.beginTransaction();
try {
URL url = new URL(csvFile);
Log.i("dl", "start");
InputStream input = url.openStream();
CSVReader reader = new CSVReader(new InputStreamReader(input));
Log.i("dl", "after reading");
String [] sched;
while ((sched = reader.readNext()) != null) {
if(sched[INDEX_CITY].equals("")) sched[INDEX_CITY]="OTHERS";
try {
db.addRow(sched[INDEX_SIN], sched[INDEX_CITY],
sched[INDEX_START_DATE], sched[INDEX_START_TIME],
sched[INDEX_END_DATE], sched[INDEX_END_TIME],
sched[INDEX_DETAILS], sched[INDEX_REASON]);
} catch (IndexOutOfBoundsException e) {
db.addRow(sched[INDEX_SIN], sched[INDEX_CITY],
sched[INDEX_START_DATE], sched[INDEX_START_TIME],
sched[INDEX_END_DATE], sched[INDEX_END_TIME],
"", sched[INDEX_REASON]);
//e.printStackTrace();
}
}
input.close();
Log.i("dl", "finished");
} catch (MalformedURLException e) {
e.printStackTrace();
db.endTransaction();
} catch (IOException e) {
e.printStackTrace();
db.endTransaction();
}
Log.d("Count", ""+db.count());
db.setTransactionSuccessful();
db.endTransaction();
writeUploadDateInTextFile();
}
});
#SuppressWarnings("unqualified-field-access")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.pms_main);
Button home = (Button) findViewById(R.id.home);
home.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, MeralcoSuite_TabletActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();
}
});
homeText1 = (TextView) findViewById(R.id.home_text1);
homeText2 = (TextView) findViewById(R.id.home_text2);
homeText3 = (TextView) findViewById(R.id.home_text3);
homeText4 = (TextView) findViewById(R.id.home_text4);
homeText1.setVisibility(View.INVISIBLE);
homeText2.setVisibility(View.INVISIBLE);
homeText3.setVisibility(View.INVISIBLE);
homeText4.setVisibility(View.INVISIBLE);
getUploadDate();
try {
getUploadDateThread.join(); //wait for upload date
Log.d("getUploadDate","thread died, upload date=" + str);
if(dbExists()){
db = new DatabaseHandler(MainActivity.this);
Log.d("Count", "" + db.count());
db.close();
if(!uploadDateEqualsDateInFile()){
dropOldSchedule();
dropThread.join();
triggerDownload();
}
showDisclaimer();
Log.i("oncreate", "finished!");
return;
}
triggerDownload();
showDisclaimer();
Log.i("oncreate", "finished!");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void dropOldSchedule(){
if(pd!=null && pd.isShowing())
pd.setTitle("Getting upload date...");
else
pd = ProgressDialog.show(this, "Getting upload date",
"This may take a few minutes...", true, false);
dropThread.start();
}
public void triggerDownload() {
if (!checkInternet()) {
showAlert("An internet connection is required to perform an update, please check that you are connected to the internet");
return;
}
if(pd!=null && pd.isShowing())
pd.setTitle("Getting upload date...");
else
pd = ProgressDialog.show(this, "Getting upload date",
"This may take a few minutes...", true, false);
downloadThread.start();
}
public void getUploadDate() {
Log.d("getUploadDate", "getting upload date of schedule");
if(pd!=null && pd.isShowing())
pd.setTitle("Getting upload date...");
else
pd = ProgressDialog.show(this, "Getting upload date",
"This may take a few minutes...", true, false);
getUploadDateThread.start();
}
public void writeUploadDateInTextFile() {
Log.d("writeUploadDateTextFile", "writing:"+str);
try {
OutputStreamWriter out = new OutputStreamWriter(openFileOutput(
"update.txt", 0));
out.write(str);
out.close();
} catch (java.io.IOException e) {
e.printStackTrace();
}
}
public void showDisclaimer() {
Log.d("ShowDisclaimer", "showing disclaimer");
homeText3
.setText("..." + str
+ "...");
homeText1.setVisibility(View.VISIBLE);
homeText2.setVisibility(View.VISIBLE);
homeText3.setVisibility(View.VISIBLE);
homeText4.setVisibility(View.VISIBLE);
Log.d("showDisclaimer", "finished showing disclaimer");
}
public boolean uploadDateEqualsDateInFile() {
Log.d("uploadDateEqualsDateInFile","comparing schedule upload dates");
try {
String recordedDate = "";
InputStream instream = openFileInput("update.txt");
if (instream != null) { // if file the available for reading
Log.d("uploadDateEqualsDateInFile","update.txt found!");
InputStreamReader inputreader = new InputStreamReader(instream);
BufferedReader buffreader = new BufferedReader(inputreader);
String line = null;
while ((line = buffreader.readLine()) != null) {
recordedDate = line;
Log.d("uploadDateEqualsDateInFile","recorded:"+recordedDate);
}
Log.d("uploadDateEqualsDateInFile","last upload date: " + str + ", recorded:" +recordedDate);
if(str.equals(recordedDate)) return true;
return false;
}
Log.d("uploadDateEqualsDateInFile","update.txt is null!");
return false;
} catch (FileNotFoundException e) {
e.printStackTrace();
return false;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
public boolean checkInternet() {
ConnectivityManager cm = (ConnectivityManager) this
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo infos[] = cm.getAllNetworkInfo();
for (NetworkInfo info : infos)
if (info.getState() == NetworkInfo.State.CONNECTED
|| info.getState() == NetworkInfo.State.CONNECTING) {
return true;
}
return false;
}
public boolean dbExists() {
File database=getApplicationContext().getDatabasePath(DatabaseHandler.DATABASE_NAME);
if (!database.exists()) {
Log.i("Database", "Not Found");
return false;
}
Log.i("Database", "Found");
return true;
}
#Override
protected void onDestroy() {
super.onDestroy();
if (db != null) {
db.close();
}
}
#Override
protected void onPause() {
super.onPause();
if (db != null) {
db.close();
}
}
}
Sorry but I couldn't find mistakes or problems in your code. But I would strongly recommend you to use AsyncTask for doing something in different thread. AsyncTask is very easy to use and I would say that it is one of the biggest advantages of java. I really miss it in obj-c.
http://labs.makemachine.net/2010/05/android-asynctask-example/
http://marakana.com/s/video_tutorial_android_application_development_asynctask_preferences_and_options_menu,257/index.html
check those links hope that will help you.
It was already mentioned that AsyncTask is the better alternative. However, it may be the case, that your call to join will throw InterruptedException. Try to use it like this:
while(getUploadDateThread.isRunning()){
try{
getUploadDateThread.join();
} catch (InterruptedException ie){}
}
// code after join
I think the problem that your facing is that you are blocking the UI thread when you call join in the onCreate() method. You should move this code into another thread which should execute in the background and once its done you can update the UI.
Here is a sample code:
final Thread t1 = new Thread();
final Thread t2 = new Thread();
t1.start();
t2.start();
new Thread(new Runnable() {
#Override
public void run() {
// Perform all your thread joins here.
try {
t1.join();
t2.join();
} catch (Exception e) {
// TODO: handle exception
}
// This thread wont move forward unless all your threads
// mentioned above are executed or timed out.
// ------ Update UI using this method
runOnUiThread(new Runnable() {
#Override
public void run() {
// Update UI code goes here
}
});
}
}).start();
Related
We have an main activity with a Text View which is requested to auto-retrieve data from TCP server in LAN.
We enabled AsyncTask in updateData() to call Connect to call Handler to update TextView named mTvVoc, and refresh connection by beginConnect().
The problem is the mTvVoc is not updated, it seems the AsyncTask does not function as expected?
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
updateData();
}
public void updateData(final String order) {
Connect(HOST, PORT, order);
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
System.out.println("get data from order--->" + order);
beginConnect(HOST, PORT, order);
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
}
}.execute();
}
public String Connect(final String HOST, final int PORT, final String OderType) {
new Thread(new Runnable() {
#Override
public void run() {
try {
socket = new Socket(HOST, PORT);
bufferedInputStream = new BufferedInputStream(socket.getInputStream());
System.out.println("bufferedInputStream--->" + bufferedInputStream);
printWriter = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
if (socket.isConnected()) {
if (!socket.isOutputShutdown()) {
printWriter.println(Integer.toHexString(Integer
.parseInt(OderType)));
}
}
while (true) {
if (!socket.isClosed() && socket.isConnected() && !socket.isInputShutdown()) {
int temp = 0;
byte[] buf = new byte[1024];
while ((temp = bufferedInputStream.read(buf)) != -1) {
isConn(socket);
Log.d("Data received", new String(buf, 0, temp));
acceptinfo = new String(buf, 0, temp);
System.out.println("Data received====》" + acceptinfo);
Message message = new Message();
message.what = 1;
message.obj = acceptinfo;
handler.sendMessage(message);
}
}
}
} catch (UnknownHostException e) {
System.out.println("UnknownHostException-->connection failed");
stopConnect();
e.printStackTrace();
} catch (IOException e) {
System.out.println("IOException-->connection failed");
stopConnect();
e.printStackTrace();
}
}
}).start();
return acceptinfo;
}
public String beginConnect(final String HOST, final int PORT, final String OderType) {
new Thread(new Runnable() {
#Override
public void run() {
try {
socket = new Socket(HOST, PORT);
bufferedInputStream = new BufferedInputStream(socket.getInputStream());
System.out.println("bufferedInputStream--->" + bufferedInputStream);
printWriter = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
if (socket.isConnected()) {
if (!socket.isOutputShutdown()) {
printWriter.println(Integer.toHexString(Integer.parseInt(OderType)));
}
}
} catch (UnknownHostException e) {
System.out.println("UnknownHostException-->connection failed");
stopConnect();
e.printStackTrace();
} catch (IOException e) {
System.out.println("IOException-->connection failed");
stopConnect();
e.printStackTrace();
}
}
}).start();
return acceptinfo;
}
public Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Log.i("message", msg.obj.toString());
if (msg.what == 0) {
mIvContent.setImageResource(R.drawable.wangluo_gray);
Toast.makeText(MainActivity.this, "Server connection failed", Toast.LENGTH_SHORT).show();
reGetData();
}
if (msg.what == 1) {
String info = msg.obj.toString();
if (info.length() != 18) {
mIvContent.setImageResource(R.drawable.wangluo_gray);
System.out.println("data verification failed");
reGetData();
return;
}
String iszeroupString = info.substring(1, 3);
String temperature = Integer.toString(Integer.parseInt(info.substring(3, 5), 16));
String vocValue = Integer.toString(Integer.parseInt(info.substring(7, 9), 16));
mTvVoc.setText(getVOC((Integer.valueOf(vocValue ) / 100.00)));
}
}
}
You cannot directly communicate from background thread to UI thread to
update any UI components.
Use this in your background thread to update textview from AsyncTask.
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
Log.d("UI thread", "I am the UI thread");
// update your text here
}
});
To update on UI, you need to run the codes in UIThread. See code below and put in your handler:
runOnUiThread(new Runnable() {
#Override
public void run() {
Log.i("message", msg.obj.toString());
if (msg.what == 0) {
mIvContent.setImageResource(R.drawable.wangluo_gray);
Toast.makeText(MainActivity.this, "Server connection failed", Toast.LENGTH_SHORT).show();
reGetData();
}
if (msg.what == 1) {
String info = msg.obj.toString();
if (info.length() != 18) {
mIvContent.setImageResource(R.drawable.wangluo_gray);
System.out.println("data verification failed");
reGetData();
return;
}
String iszeroupString = info.substring(1, 3);
String temperature = Integer.toString(Integer.parseInt(info.substring(3, 5), 16));
String vocValue = Integer.toString(Integer.parseInt(info.substring(7, 9), 16));
mTvVoc.setText(getVOC((Integer.valueOf(vocValue ) / 100.00)));
}
}
});
Pretty bad to code that handler to update the gui. Do away with it as AsyncTask provides already the functionality to do so.
You should have looked better at the many examples.
Use publishProgress() and onProgressUpdate() to update a progress bar and/or other gui elements.
And do not wrap your code in a thread if it has to be executed in doInBackground().
I got problem with my asyncTask. I have my custom USB Scanner. I want to turn it on and off with ToggleButton. Scanning works fine but asynctask completly blocks user interface. I can't do nothing. Maybe you know what can I do to make it works better ?
Here's toggleButton :
mScanLayout.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if(isChecked)
task.execute();
if(!isChecked)
task.cancel(true);
}
});
Here is asynctask :
public class scanAsyncTask extends AsyncTask<Void,Void,Void> {
#Override
protected Void doInBackground(Void... params) {
while(!isCancelled()) {
mActivity.runOnUiThread(new Runnable() {
#Override
public void run() {
adapter = new PartAdapter(getContext(), R.layout.part_item, mParts, mActivity,this);
adapter.startScanning();
}
});
}
return null;
}
}
And this is scanning method from adapter :
public void startScanning(){
final PendingIntent mPermissionIntent = PendingIntent.getBroadcast(getContext(), 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
getContext().registerReceiver(usbReceiver, filter);
UsbManager usbManager = (UsbManager) getContext().getSystemService(Context.USB_SERVICE);
HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
UsbDevice device = null;
while (deviceIterator.hasNext()) {
device = deviceIterator.next();
if (device.getVendorId() == 1659 && device.getProductId() == 8963) {
this.device = device;
usbManager.requestPermission(device, mPermissionIntent);
break;
}
}
final UsbDevice finalDevice = device;
final UsbDevice finalDevice1 = device;
UsbConnector.CallbackListener listener = new UsbConnector.CallbackListener() {
#Override
public void onStatusChanged(UsbConnector.Status newStatus) {
Toast.makeText(getContext(), "status: " + newStatus, Toast.LENGTH_SHORT).show();
}
#Override
public void onScanCompleted(String result) {
Toast.makeText(getContext(), "result: " + result, Toast.LENGTH_SHORT).show();
}
};
UsbConnector connector = new UsbConnector(getContext(), finalDevice1,listener);
connector.run();
UsbDeviceConnection usbDeviceConnection = usbManager.openDevice(finalDevice);
UsbSerialDevice serial = UsbSerialDevice.createUsbSerialDevice(finalDevice, usbDeviceConnection);
serial.open();
serial.setBaudRate(57600);
if (finalDevice1 != null) {
connector.run();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
connector.send(pal);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
byte[] received = connector.receive(36);
if (received == null) {
Toast.makeText(getContext(), "BĹ‚Ä…d inicjalizacji skanera", Toast.LENGTH_SHORT).show();
}
if (received != null) {
String response = null;
long longValue = ByteBuffer.wrap(received).getLong();
response = Long.toHexString(longValue).toUpperCase();
if (response.contains("DAAD0674016F6B26")) {
connector.send(readId);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
byte[] receivedTag = connector.receive(36);
if (receivedTag != null) {
String tag = null;
long tagValue = ByteBuffer.wrap(receivedTag).getLong();
tag = Long.toHexString(tagValue).toUpperCase();
if (tag.contentEquals("DAAD046F62ADA900")) {
startScanning();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (!tag.contains("DAAD046F62ADA900")) {
String tag2 = null;
long tagValue2 = ByteBuffer.wrap(receivedTag).getLong();
tag2 = Long.toHexString(tagValue2).toUpperCase();
Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Ringtone r = RingtoneManager.getRingtone(getContext(), notification);
r.play();
int i = 0;
for (Part part : mParts) {
if(part.getCode().contains(tag2)) {
part.setScan(true);
part.setScanCounter(part.getScanCounter() + 1);
i++;
notifyDataSetChanged();
}
}
if(i==0){
Intent intent = new Intent(getContext(),AddActivity.class);
intent.putExtra("tag",tag2);
mActivity.startActivityForResult(intent,2);
}
}
}
}
notifyDataSetChanged();
}
} else {
Toast.makeText(getContext(), R.string.plug_scanner, Toast.LENGTH_SHORT).show();
}
}
Please, help.
in your doInBackground you do:
mActivity.runOnUiThread(new Runnable() {
That defeats the purpose and you do not execute on the background anymore - you are on the main-thread and so block the UI
This Line of your code
mActivity.runOnUiThread(new Runnable() {
Runs on UI thread you should return result in doinbackground and then use it in onPostExecute which runs on UI thread. doInBackground is made to run on background not on UI thread but you forcing it to run on UI thread
My code have more than one thread and Runnable. My problem is i change the value of a certain variable in the thread that the Runnable calling .
After the calling i make a check on that variable value but the value was not retrieved yet.
How can i retrieve the value after the processing? Here is the Runnable and the Thread code:
final Runnable r = new Runnable()
{
public void run()
{
if(flag==true)
onSwipe();
if(SwipeAgain==true)
handler.postDelayed(this, 1000);
}
};
private void onSwipe() {
new Thread() {
public void run() {
String data = null;
decryption_data = null;
encryption_data = null;
SwipeAgain=false;
handler.post(clear_encryption);
try {
data = sreader.ReadCard(15000);
} catch (Exception ex) {
if (ex instanceof TimeoutException) {
return;
} else
CloseSinWave();
}
if (data == null) {
SwipeAgain=true;
encryption_data = sreader.GetErrorString();
if (encryption_data.equalsIgnoreCase("cancel all"))
return;
handler.post(display_encryptiondata);
} else {
encryption_data = "\n" + data;
handler.post(display_encryptiondata);
}.start();
}
SwipeAgain is the value i want after processing
You have to use Callable, Runnable interface do not pass values to the parent method.
See this example.
You may require to use Generic Objects
Use a MONITOR final Object to wait and notify it when processing is done.
private final MONITOR Object[] = new Object[0];
private AtomicBoolean ready = new AtomicBoolean(false);
final Runnable r = new Runnable() {
public void run()
{
if(flag==true){
ready.set(false);
onSwipe();
synchronized(MONITOR){
if(!ready.get()){
try{
MONITOR.wait(); //will block until it get notified
}catch(InteruptedException e){}
}
}
}
if(SwipeAgain==true)
handler.postDelayed(this, 1000);
}
};
private void onSwipe() {
new Thread() {
public void run() {
try{
String data = null;
decryption_data = null;
encryption_data = null;
SwipeAgain=false;
handler.post(clear_encryption);
try {
data = sreader.ReadCard(15000);
} catch (Exception ex) {
if (ex instanceof TimeoutException) {
return;
} else
CloseSinWave();
}
if (data == null) {
SwipeAgain=true;
encryption_data = sreader.GetErrorString();
if (encryption_data.equalsIgnoreCase("cancel all"))
return;
handler.post(display_encryptiondata);
} else {
encryption_data = "\n" + data;
handler.post(display_encryptiondata);
}finally{
synchronized(MONITOR){
ready.set(true);
MONITOR.notifyAll(); //notify (and so unblock r.run())
}
}
}.start();
}
I am having problems making my TextViews visible from another thread using the method showDisclaimer(). I have used runOnUiThread() to set the visibility of my TextViews. Basically, I want to show these views after importing the csv to the database. Can you take a look and see what I missed?
public class MainActivity extends Activity {
final static int INDEX_ACCTTYPE = 0;
final static int INDEX_ECN = 1;
final static int INDEX_TLN = 2;
final static int INDEX_SIN = 3;
final static int INDEX_MOBILE = 4;
final static int INDEX_CITY = 5;
final static int INDEX_START_DATE = 6;
final static int INDEX_START_TIME = 7;
final static int INDEX_END_DATE = 8;
final static int INDEX_END_TIME = 9;
final static int INDEX_REASON = 10;
final static int INDEX_DETAILS = 11;
DatabaseHandler db;
String str;
ProgressDialog pd;
final private String csvFile = "http://www.meralco.com.ph/pdf/pms/pms_test.csv";
final private String uploadDateFile = "http://www.meralco.com.ph/pdf/pms/UploadDate_test.txt";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView homeText1 = (TextView) findViewById(R.id.home_text1);
TextView homeText2 = (TextView) findViewById(R.id.home_text2);
TextView homeText3 = (TextView) findViewById(R.id.home_text3);
TextView homeText4 = (TextView) findViewById(R.id.home_text4);
homeText1.setVisibility(View.INVISIBLE);
homeText2.setVisibility(View.INVISIBLE);
homeText3.setVisibility(View.INVISIBLE);
homeText4.setVisibility(View.INVISIBLE);
//db = new DatabaseHandler(MainActivity.this);
if(dbExists()){
db = new DatabaseHandler(MainActivity.this);
Log.d("Count", "" + db.count());
if(!uploadDateEqualsDateInFile())
promptOptionalUpdate("There is a new schedule");
showDisclaimer();
Log.i("oncreate", "finished!");
return;
}
promptRequiredUpdate("Schedule not updated");
//showDisclaimer();
Log.i("oncreate", "finished!");
}
public void promptOptionalUpdate(String Message) {
AlertDialog.Builder builder = new AlertDialog.Builder(
this);
builder.setMessage(Message)
.setCancelable(false)
.setPositiveButton("Update Now",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Log.d("SHOW ALERT -->!", "update");
dropOldSchedule();
triggerDownload();
dialog.cancel();
}
})
.setNegativeButton("Later",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Log.d("SHOW ALERT -->!", "cancel");
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
public void dropOldSchedule(){
//TODO drop old schedule
}
public void triggerDownload() {
if (!checkInternet()) {
showAlert("An internet connection is required to perform an update, please check that you are connected to the internet");
return;
}
if(pd!=null && pd.isShowing()) pd.dismiss();
pd = ProgressDialog.show(this, "Downloading schedule",
"This may take a few minutes...", true, false);
Thread thread = new Thread(new Runnable() {
public void run() {
db = new DatabaseHandler(MainActivity.this);
db.beginTransaction();
try {
URL myURL = new URL(csvFile);
BufferedReader so = new BufferedReader(new InputStreamReader(myURL.openStream()));
while (true) {
String output = so.readLine();
if (output != null) {
String[] sched = output.split(",");
try {
db.addRow(sched[INDEX_SIN], sched[INDEX_CITY],
sched[INDEX_START_DATE], sched[INDEX_START_TIME],
sched[INDEX_END_DATE], sched[INDEX_END_TIME],
sched[INDEX_DETAILS], sched[INDEX_REASON]);
} catch (IndexOutOfBoundsException e) {
db.addRow(sched[INDEX_SIN], sched[INDEX_CITY],
sched[INDEX_START_DATE], sched[INDEX_START_TIME],
sched[INDEX_END_DATE], sched[INDEX_END_TIME],
"", sched[INDEX_REASON]);
e.printStackTrace();
}
}
else {
break;
}
}
so.close();
} catch (MalformedURLException e) {
e.printStackTrace();
db.endTransaction();
} catch (IOException e) {
e.printStackTrace();
db.endTransaction();
}
Log.d("Count", ""+db.count());
db.setTransactionSuccessful();
db.endTransaction();
runOnUiThread(new Runnable() {
public void run() {
while (!pd.isShowing());
getUploadDate();
writeUploadDateInTextFile();
showDisclaimer();
pd.dismiss();
}
});
}
});
thread.start();
//while(thread.isAlive());
Log.d("triggerDownload", "thread died, finished dl. showing disclaimer...");
}
public void getUploadDate() {
Log.d("getUploadDate", "getting upload date of schedule");
if(pd!=null && pd.isShowing()) pd.dismiss();
pd = ProgressDialog.show(this, "Getting upload date",
"This may take a few minutes...", true, false);
Thread thread = new Thread(new Runnable() {
public void run() {
try {
URL myURL = new URL(uploadDateFile);
BufferedReader so = new BufferedReader(new InputStreamReader(myURL.openStream()));
while (true) {
String output = so.readLine();
if (output != null) {
str = output;
}
else {
break;
}
}
so.close();
}
catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
runOnUiThread(new Runnable() {
public void run() {
while (!pd.isShowing());
pd.dismiss();
}
});
}
});
thread.start();
while (thread.isAlive());
Log.d("getUploadDate","thread died, upload date="+str);
}
public void writeUploadDateInTextFile() {
Log.d("writeUploadDateTextFile", "writing:"+str);
try {
OutputStreamWriter out = new OutputStreamWriter(openFileOutput(
"update.txt", 0));
out.write(str);
out.close();
} catch (java.io.IOException e) {
e.printStackTrace();
}
}
public void showDisclaimer() {
Log.d("ShowDisclaimer", "showing disclaimer");
TextView homeText1x = (TextView) findViewById(R.id.home_text1);
TextView homeText2x = (TextView) findViewById(R.id.home_text2);
TextView homeText3x = (TextView) findViewById(R.id.home_text3);
TextView homeText4x = (TextView) findViewById(R.id.home_text4);
homeText3x
.setText("You may view the schedule of pre-arranged power interruptions by clicking any of these buttons : SIN, City or Date. " +
"The schedule has been updated as of " + str
+ ". Meralco is exerting all efforts to restore electric service as scheduled." +
" The schedule, however, may change without further notice. For verification, follow-ups, or " +
"latest updates, please contact our CALL CENTER through telephone nos. 16211, " +
"fax nos. 1622-8554/1622-8556 or email address callcenter.tech.assist#meralco.com.ph.");
homeText1x.setVisibility(View.VISIBLE);
homeText2x.setVisibility(View.VISIBLE);
homeText3x.setVisibility(View.VISIBLE);
homeText4x.setVisibility(View.VISIBLE);
Log.d("ShowDisclaimer", "finished showing disclaimer");
}
public void promptRequiredUpdate(String Message) {
Log.d("required update","required!");
AlertDialog.Builder builder = new AlertDialog.Builder(
this);
builder.setMessage(Message)
.setCancelable(false)
.setPositiveButton("Update Now",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Log.d("SHOW ALERT -->!", "update");
triggerDownload();
dialog.cancel();
}
})
.setNegativeButton("Later",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Log.d("SHOW ALERT -->!", "cancel");
dialog.cancel();
finish();
}
});
AlertDialog alert = builder.create();
alert.show();
}
public boolean uploadDateEqualsDateInFile() {
Log.d("uploadDateEqualsDateInFile","comparing schedule upload dates");
getUploadDate();
try {
String recordedDate = "";
InputStream instream = openFileInput("update.txt");
if (instream != null) { // if file the available for reading
Log.d("uploadDateEqualsDateInFile","update.txt found!");
InputStreamReader inputreader = new InputStreamReader(instream);
BufferedReader buffreader = new BufferedReader(inputreader);
String line = null;
while ((line = buffreader.readLine()) != null) {
recordedDate = line;
Log.d("uploadDateEqualsDateInFile","recorded:"+recordedDate);
}
Log.d("uploadDateEqualsDateInFile","last upload date: " + str + ", recorded:" +recordedDate);
if(str.equals(recordedDate)) return true;
return false;
}
Log.d("uploadDateEqualsDateInFile","update.txt is null!");
return false;
} catch (FileNotFoundException e) {
e.printStackTrace();
return false;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
public void showAlert(String Message) {
AlertDialog.Builder builder = new AlertDialog.Builder(getBaseContext());
builder.setMessage(Message).setCancelable(false)
.setNeutralButton("Ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
public boolean checkInternet() {
ConnectivityManager cm = (ConnectivityManager) this
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo infos[] = cm.getAllNetworkInfo();
for (NetworkInfo info : infos)
if (info.getState() == NetworkInfo.State.CONNECTED
|| info.getState() == NetworkInfo.State.CONNECTING) {
return true;
}
return false;
}
public boolean dbExists() {
File database=getApplicationContext().getDatabasePath(DatabaseHandler.DATABASE_NAME);
if (!database.exists()) {
Log.i("Database", "Not Found");
return false;
}
Log.i("Database", "Found");
return true;
}
#Override
protected void onDestroy() {
super.onDestroy();
if (db != null) {
db.close();
}
}
#Override
protected void onPause() {
super.onPause();
if (db != null) {
db.close();
}
}
}
simplymoody, do what Chirag Raval suggested by declaring private static TextView homeText1, globally and in your onCreate initialise them. However, you should always update the UI from the main thread. But showDisclaimer() is still running on the background thread, so you could run the showDisclaimer() a couple of different ways. One would be to do what you have done in getUploadDate():
runOnUiThread(new Runnable() {
public void run() {
showDisclaimer()
}
});
Or you could use a handler:
private Handler showDisclaimerHandler = new Handler(new Handler.Callback() {
#Override
public boolean handleMessage(Message msg) {
homeText3x.setText("TEXT");
homeText1x.setVisibility(View.VISIBLE);
homeText2x.setVisibility(View.VISIBLE);
homeText3x.setVisibility(View.VISIBLE);
homeText4x.setVisibility(View.VISIBLE);
Log.d("ShowDisclaimer", "finished showing disclaimer");
return false;
}
});
And everywhere in a background thread you wish to run your showDisclaimer(), instead you run:
showDisclaimerHandler.sendEmptyMessage(0);
I am getting this error
java.lang.NullPointerException at android.content.ContextWrapper.getPackageManager
when am trying to get list of all installed applications on the device.
I have a server that starts when my application is started, and the client pings the server and asks to get a list of installed applications. The Server then asks the getPackageManager() and gets all the installed applications.
But the getPackageManager throws a NullPointerException.
The Server is written in a java and is started from my android application.
Could someone please tell me what am missing and why I am getting this error?
Please find the code below
public class ApplicationRecognition extends Activity {
// android.os.Debug.waitForDebugger();
Button buttonStart, buttonStop;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
buttonStart = (Button) findViewById(R.id.buttonStart);
buttonStop = (Button) findViewById(R.id.buttonStop);
final SecurityModuleServer server = new SecurityModuleServer(5902);
server.start();
Toast.makeText(this, "Application Server is started", Toast.LENGTH_SHORT).show();
buttonStart.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
startService(new Intent(getBaseContext(), AppReconService.class));
}});
buttonStop.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
stopService(new Intent(getBaseContext(), AppReconService.class));
}});
}
public String[] getInstalledApplications()
{
String[] appname =new String[10];
Intent mainIntent = new Intent(Intent.ACTION_MAIN,null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
PackageManager manager = getPackageManager();
List<ResolveInfo> pkgAppsList = manager.queryIntentActivities(mainIntent, 0);
appname = new String[pkgAppsList.size()];
for(int i=0;i<pkgAppsList.size();i++)
{
appname[i]=pkgAppsList.get(i).activityInfo.packageName;
}
return appname;
}
}
the server side code
public class SecurityModuleServer implements Observer,Runnable
{
private int numberOfConnectedClient;
private Thread serverThread;
private ServerSocket serverSocket;
private volatile boolean isServerRunning;
public SecurityModuleServer(final int port)
{
numberOfConnectedClient = 0;
try
{
serverSocket = new ServerSocket(port);
} catch (IOException e) {
e.printStackTrace();
}
}
public void run()
{
System.out.println("SecurityModuleServer>> server thread started."); //$NON-NLS-1$
while(isServerRunning)
{
numberOfConnectedClient++;
try
{
SecurityModuleClientThread client = new SecurityModuleClientThread(serverSocket.accept(), numberOfConnectedClient);
client.addObserver(this);
client.start();
}
catch (IOException e)
{
e.printStackTrace();
}
}
System.out.println("SecurityModuleServer>> server thread stopped."); //$NON-NLS-1$
}
synchronized public void start()
{
serverThread = new Thread(this);
isServerRunning = true;
serverThread.start();
}
synchronized public void stop()
{
isServerRunning = false;
}
public boolean isRunning()
{
return isServerRunning;
}
public static void main(String[] args)
{
SecurityModuleServer server = new SecurityModuleServer(5903);
server.start();
}
public void update(Observable o, Object arg)
{
numberOfConnectedClient--;
}
}
the client side code
public SecurityModuleClientThread(Socket socket, int numberOfClient)
{
clientSocket = socket;
numberOfConnectedClient = numberOfClient;
try
{
printOut = new PrintStream(clientSocket.getOutputStream());
readerIn = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
clientThread = new Thread(this);
}
catch (IOException e)
{
e.printStackTrace();
}
}
public void run()
{
Looper.prepare();
String input = ""; //$NON-NLS-1$
System.out.println("SecurityModuleClientThread>> thread started for client."); //$NON-NLS-1$
if (numberOfConnectedClient <= MAX_ALLOWED_CLIENTS)
{
printOut.println(CMD+Answer_Open_Connection+SEPARATOR+M002);
while(isClientRunning)
{
try
{
input = readerIn.readLine();
System.out.println("Message received>> "+input); //$NON-NLS-1$
parseInputMessage(input);
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
else
{
printOut.println(CMD+Error+SEPARATOR+M003);
stop();
}
System.out.println("SecurityModuleClientThread>> thread stopped for client."); //$NON-NLS-1$
}
private void parseInputMessage(final String input)
{
if (input.equalsIgnoreCase(CMD+Request_Close_Connection))
{
printOut.println(CMD+Answer_Close_Connection+SEPARATOR+M007);
stop();
}
else
{
String messages[] = input.split(SEPARATOR);
// Parse the command
switch(parseCommand(messages[0]))
{
case Request_Start_Application:
if(parseApplicationName(input) != null)
{
if(startAndroidApplication(parseApplicationName(input)))
{
// TODO
printOut.println(CMD+Answer_Start_Application);
startAndroidApplication(parseApplicationName(input));
}
else
{
printOut.println(CMD+Error+SEPARATOR+M004);
}
}
else
{
printOut.println(CMD+Error+SEPARATOR+M004);
}
break;
case Request_Stop_Application:
if(parseApplicationName(input) != null)
{
if (stopAndroidApplication(parseApplicationName(input)))
{
// TODO
printOut.println(CMD+Answer_Stop_Application);
}
else
{
printOut.println(CMD+Error+SEPARATOR+M004);
}
}
else
{
printOut.println(CMD+Error+SEPARATOR+M004);
}
break;
case Request_Application_Installed:
String[] appnames = new String[provideInstalledApplication().length];
appnames = provideInstalledApplication();
for(int i=0;i<appnames.length;i++)
{
printOut.println(appnames[i]);
}
break;
case Request_Application_Running:
//TODO
break;
default:
printOut.println(CMD+Error+SEPARATOR+M008);
break;
}
}
}
private int parseCommand(String cmd)
{
if (cmd.length() == 6)
{
return Integer.parseInt(cmd.substring(3, 6));
}
else
{
return 0;
}
}
private String parseApplicationName(String message)
{
if (message.length() > 6)
{
// TODO
return message.substring(6, message.length());
}
else
{
return null;
}
}
public synchronized void start()
{
isClientRunning = true;
clientThread = new Thread(this);
clientThread.start();
}
public synchronized void stop()
{
printOut.close();
try
{
readerIn.close();
clientSocket.close();
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
isClientRunning = false;
setChanged();
notifyObservers();
}
}
public boolean isRunning()
{
return isClientRunning;
}
public String[] provideInstalledApplication()
{
String[] appnames = null;
ApplicationRecognition apprecon = new ApplicationRecognition();
appnames=new String[apprecon.getInstalledApplications().length];
appnames = apprecon.getInstalledApplications();
return appnames;
}
public String[] provideRunningApplication()
{
// TODO Auto-generated method stub
return null;
}
public boolean startAndroidApplication(String applicationName)
{
// TODO Auto-generated method stub
ApplicationRecognition apprecon = new ApplicationRecognition();
apprecon.startApplication(applicationName);
return false;
}
public boolean stopAndroidApplication(String applicationName)
{
// TODO Auto-generated method stub
return false;
}
}
The main part that is giving me trouble is in ApplicationRecognition class under method getInstalledApplications() in getPackageManager is null.
This method is called from the client side SecurityModuleClientThread class, provideInstalledApplication method.
Can someone please tell me where am I going wrong.