I have two activities, my MainActivity runs TimerTask which increments "counter" value.
public class MainActivity extends AppCompatActivity {
public static int counter = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Handler handler = new Handler();
Timer timer = new Timer();
TimerTask timerTask = new TimerTask() {
public void run() {
handler.post(new Runnable() {
public void run() {
counter++;
}
});
}
};
timer.schedule(timerTask, 0, 1000);
Intent intent = new Intent(this, MapActivity.class);
startActivity(intent);
}
}
My MapActivity is supposed to read this value upon button click.
public class MapActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
}
public void readCounter(View view){
Log.d("counter:", Integer.toString(MainActivity.counter));
}
}
Currently counter is declared as public static variable but since static variables are bad practice, what would be proper and elegant way to do it?
There's nothing wrong with static values. In face if you want to make it MVC and use model, you should probably wrap this value with a Singleton Model class.
But to simplify things I would only recommend to make sure you reset the value on MainActivity onCreate.
The android way to do it would be using services or startActivityForResult.
Bundles are used to add extra parameters to pass to the called activity. So you can get and use this extra parameter as you wish.
Here is how to do it:
in MainActivity:
Intent intent = new Intent(this, MapActivity.class);
intent.putExtra("counter", counter);
startActivity(intent);
in MapActivity:
Bundle extras = getIntent().getExtras();
int counter = extras.getIntExtra("counter");
EDIT 1: For continuous update use custom listener interface
public class MainActivity extends AppCompatActivity {
public static int counter = 0;
private MyCounterUtil util;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Handler handler = new Handler();
util = MyCounterUtil.getInstance();
Timer timer = new Timer();
TimerTask timerTask = new TimerTask() {
public void run() {
handler.post(new Runnable() {
public void run() {
counter++;
util.notifyUpdate(counter);
}
});
}
};
timer.schedule(timerTask, 0, 1000);
Intent intent = new Intent(this, MapActivity.class);
startActivity(intent);
}
}
Create this class
public class MyCounterUtil {
private static MyCounterUtil mInstance;
private MyCounterListener mListener;
private MyCounterUtil() {}
public static MyCounterUtil getInstance() {
if(mInstance == null) {
mInstance = new MyCounterUtil();
}
return mInstance;
}
public void setListener(MyCounterListener listener) {
mListener = listener;
}
private void notifyUpdate(int count) {
if(mListener != null)
mListener.onUpdate(count);
}
public interface MyCounterListener{
public void onUpdate(int count);
}
}
Implement listener interface in MapActivity
public class MapActivity extends AppCompatActivity implements MyCounterListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
MyCounterUtil.getInstance().setListener(this);
}
/*
public void readCounter(View view){
Log.d("counter:", Integer.toString(MainActivity.counter));
}
*/
#Override
public void onUpdate(int count){
Log.d("counter:", Integer.toString(count));
}
}
EDIT 2:
Another clean and simple approach without TimerTask is using system time as counter and pass its first value with intent or sharedpreferences.
in MainActivity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/*
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = preferences.edit();
editor.putLong("startTime", System.currentTimeMillis());
editor.apply();
*/
Intent intent = new Intent(this, MapActivity.class);
intent.putExtra("startTime", System.currentTimeMillis());
startActivity(intent);
}
}
in MapActivity:
public class MapActivity extends AppCompatActivity {
private long startTime;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
/* in case use of sharedpref
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
startTime = preferences.getLong("startTime", 0);
*/
//in case use of bundle
startTime = getIntent().getExtras().getLongExtra("startTime", 0);
}
public void readCounter(View view){
long counter = (System.currentTimeMillis() - startTime)/1000;
Log.d("counter:", "" + counter);
}
}
Related
I have Mybroadcastreceiver and when rintone is play stopAlarm.java page is shown If button is pressed i want to use stop ringtone. How can I use r.stop() in my stopAlarm.java
public class MyBroadcastReceiver extends BroadcastReceiver {
public static final String NOTIFICATION_CHANNEL_ID = "10001" ;
private final static String default_notification_channel_id = "default" ;
#Override
public void onReceive(Context context, Intent intent) {
Uri notificationsound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_RINGTONE);
Ringtone r = RingtoneManager.getRingtone(context,notificationsound);
r.play();
Intent i = new Intent(context,stopAlarm.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
}
}
public class stopAlarm extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_stop_alarm);
Button stop = (Button)findViewById(R.id.stopAlarm);
stop.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//////////How can I get r
}
});
}
}
public class stopAlarm extends AppCompatActivity {
Ringtone r;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_stop_alarm);
Button stop = (Button)findViewById(R.id.stopAlarm);
stop.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
r.stop();
}
});
}
I am trying to use progressbar like a 30 secs timer. It works well but when i click back button the progressbar progress continues. I am unable to reset the progressbar progress to 0 when i click the backbutton.
Here is my code:
MainAcitivty:
public class MainActivity extends AppCompatActivity {
public Button btnA;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnA = (Button)findViewById(R.id.btnA);
btnA.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intentA = new Intent(MainActivity.this,SecondActivity.class);
startActivity(intentA);
}
});
}
}
SecondActivity:
public class SecondActivity extends AppCompatActivity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Context context;
float from;
float to;
final TextView textV;
final ProgressBar mProgressBar;
CountDownTimer mCountDownTimer;
final int[] i = {0};
textV = (TextView)findViewById(R.id.tvFinal);
mProgressBar = (ProgressBar)findViewById(R.id.progressbar);
mProgressBar.setProgress(i[0]);
mCountDownTimer=new CountDownTimer(30000,1000) {
#Override
public void onTick(long millisUntilFinished) {
Log.v("Log_tag", "Tick of Progress"+ i[0] + millisUntilFinished);
i[0]++;
mProgressBar.setProgress((int) i[0] *100/(30000/1000));
}
#Override
public void onFinish() {
i[0]++;
mProgressBar.setProgress(100);
textV.setText("finish");
Intent intent = new Intent(SecondActivity.this, SecondActivity.class);
startActivity(intent);
}
};
mCountDownTimer.start();
}
}
in order to implement behaviour of back button you need to override onBackPressed() and then implement method to reset progressbar result.
Example:
#Override
public void onBackPressed() {
super.onBackPressed();
progressBar.setProgress(0);
}
Hi I just need a little bit of a helping hand in completing this shared preferences code I have.
Currently I have a class where I stored in the relevant code for SharedPreferences:
public class SharedPreferencesManager {
private static final String APP_PREFS = "AppPrefsFile";
private static final String NUMBER_OF_CLICKS = "numberOfClicks";
private SharedPreferences sharedPrefs;
private static SharedPreferencesManager instance;
private SharedPreferencesManager(Context context) {
sharedPrefs =
context.getApplicationContext().getSharedPreferences(APP_PREFS, MODE_PRIVATE);
}
public static synchronized SharedPreferencesManager getInstance(Context context){
if(instance == null)
instance = new SharedPreferencesManager(context);
return instance;
}
public void storeClicks(int count)
{
SharedPreferences.Editor editor = sharedPrefs.edit();
editor.putInt(NUMBER_OF_CLICKS, count);
editor.apply();
}
public int getNumberOfClicks(){
int clicksNumber = sharedPrefs.getInt(NUMBER_OF_CLICKS, 0);
return clicksNumber;
}
}
I want to count the number of clicks for buttons jokes, poems and funnystories from the MainActivity class and the 'select another' button from the Content class. So if each button was clicked 4 times, the total click count should be 16.
I want to keep the number of clicks count even after the app is closed and re-open. It's just the syntax of the counting of the clicks I am unsure of. I think for main activity it is correct but I am unsure on how to store it for the Content class.
TO recap, count the number of clicks for all of those buttons mentioned and this number should be accessible and updated no matter which page the user is in.
Below is the Main Activity class:
public class MainActivity extends AppCompatActivity{
final Context context = this;
int clicksCount = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SharedPreferencesManager.getInstance(context).storeClicks(clicksCount);
Button jokesButton = findViewById(R.id.button_jokes);
Button poemsButton = findViewById(R.id.button_poems);
Button funnyStoriesButton = findViewById(R.id.button_funny_stories);
jokesButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
clicksCount++;
}
});
poemsButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
clicksCount++;
}
});
funnyStoriesButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
clicksCount++;
}
});
}
Below is Content class:
public class Content extends AppCompatActivity{
Button backButton;
Button selectAnotherButton;
TextView contentText;
Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_content);
int clicksCount = SharedPreferencesManager.getInstance(context).getNumberOfClicks();
backButton = findViewById(R.id.button_back);
selectAnotherButton = findViewById(R.id.button_select_another);
selectAnotherButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
clicksCount++;
}
});
backButton.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick (View v){
finish();
}
});
}
}
Instead of having the two methods getNumberOfClicks() and storeClicks() in your SharedPreferencesManager, you could only have one like this:
public void increaseClickCount() {
int clickCount = sharedPrefs.getInt(NUMBER_OF_CLICKS, 0);
clickCount++;
SharedPreferences.Editor editor = sharedPrefs.edit();
editor.putInt(NUMBER_OF_CLICKS, clickCount);
editor.apply();
}
You call this on every click. No need for the activities to know about the clicks count.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final SharedPreferencesManager prefManager = SharedPreferencesManager.getInstance(context);
jokesButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
prefManager.increaseClickCount();
}
});
...
}
Also there's no need to store your context as a global variable because your activity is already a context itself, you can just use this or MainActivity.this for a context.
So im working on slideshow-like project, but my problem is, when im at the middle of slideshow, I want to go back at my main activity where my slideshow will start using back button on my smartphone. What happen is, it will go back as soon as I pressed back button, but the other slideshows will carry on after 3 seconds which I set in my handler.postDelayed(r1, 3000);. Please help. Thank you
public class Dad1 extends AppCompatActivity {
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dad1);
Runnable r1 = new Runnable() {
#Override
public void run() {
Intent i = new Intent(getApplicationContext(), Dad2.class);
startActivity(i);
finish();
}
};
Handler handler = new Handler();
handler.postDelayed(r1, 3000);
}
}
What you can do is keep the Handler object at the Activity level. When back button is pressed then just cancel the Handler callbacks. So in that case your Handler's run method will not be called.
Please find the sample code below:
public class Dad1 extends AppCompatActivity {
private Handler handler;
private Runnable myRunnable;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initRunnable();
handler.postDelayed(myRunnable,3000);
}
private void initRunnable() {
myRunnable = new Runnable() {
#Override
public void run() {
Intent i = new Intent(getApplicationContext(), Dad2.class);
startActivity(i);
finish();
}
};
}
#Override
public void onBackPressed() {
super.onBackPressed();
if(handler!=null){
handler.removeCallbacks(myRunnable);
}
}
}
public class CheatActivity extends AppCompatActivity {
private static final String EXTRA_ANSWER_IS_TRUE="com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN="com.example.ferhat.geoquiz.answer_shown";
private static final String CHEATER="com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mIsCheater;
public static Intent newIntent(Context packageContext, boolean answerIsTrue){
Intent i=new Intent(packageContext,CheatActivity.class);
i.putExtra(EXTRA_ANSWER_IS_TRUE,answerIsTrue);
return i;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cheat);
mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
mAnswerTextView = (TextView) findViewById(R.id.answerTextView);
mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
mShowAnswer.setOnClickListener(new View.OnClickListener() {
//Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
#Override
public void onClick(View v) {
if (mAnswerIsTrue) {
mAnswerTextView.setText(R.string.true_button);
} else {
mAnswerTextView.setText(R.string.false_button);
}
mIsCheater=true;
setAnswerShownResult();
}
});
if(savedInstanceState!=null){
mIsCheater=savedInstanceState.getBoolean(CHEATER,false);
}
}
private void setAnswerShownResult(){
Intent data=new Intent();
data.putExtra(EXTRA_ANSWER_SHOWN,mIsCheater);
setResult(RESULT_OK,data);
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putBoolean(CHEATER,mIsCheater);
}
}
I try to solve challenge in Anroid Programming, Big Nerds Ranch Guide (Chap.5)
Challenge asks me to keep Cheat data while rotation of screen and transaction between questions.Main Activity holds questions and CheatActivity has answers from Main activity. And i created BooleanArray to hold cheat data for questions.
Problem is ,i cheated for first question and then when i am in the CheatActivity(CheatPage) of other questions ,program crashes if i rotate the screen.
Error caused by this line savedInstanceState.putBoolean(CHEATER,mIsCheater);
i think i need to clear data from previous Cheat Data(BooleanArray already holding it) but i dont know how to do it.
public class CheatActivity extends AppCompatActivity {
private static final String EXTRA_ANSWER_IS_TRUE = "com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN = "com.example.ferhat.geoquiz.answer_shown";
public static final String EXTRA_CHEATED = "com.example.ferhat.geoquiz.cheated";
private static final String CHEATER = "com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mAnswerEverShown;
private Boolean twoStep=false;
//Yeni intent methodu yarattık Cevabı alıyor ve bu activity i başlatıyor
public static Intent newIntent(Context packageContext, boolean answerIsTrue, boolean checked) {
Intent i = new Intent(packageContext, CheatActivity.class);
i.putExtra(EXTRA_ANSWER_IS_TRUE, answerIsTrue);
i.putExtra(EXTRA_CHEATED, checked);
return i;
}
private void setAnswerShownResult(Boolean isAnswerShown) {
Intent data = new Intent();
**if(mAnswerEverShown) {
isAnswerShown=mAnswerEverShown;
data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
setResult(RESULT_OK, data);
}else {
data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
setResult(RESULT_OK, data);
}
twoStep=isAnswerShown;**
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cheat);
mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
mAnswerTextView = (TextView) findViewById(R.id.answerTextView);
**mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);**
mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
mShowAnswer.setOnClickListener(new View.OnClickListener() {
//Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
#Override
public void onClick(View v) {
if (mAnswerIsTrue) {
mAnswerTextView.setText(R.string.true_button);
} else {
mAnswerTextView.setText(R.string.false_button);
}
twoStep=true;
setAnswerShownResult(twoStep);
}
});
**if (savedInstanceState != null) {
setAnswerShownResult(savedInstanceState.getBoolean(CHEATER, false));
}
}
#Override
public void onSaveInstanceState (Bundle savedInstanceState){
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putBoolean(CHEATER, twoStep);
}
}**
i found solution like for every situation.
first think i did; i get info from main activity
mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);
And Then i changed setAnswerShownResult for two situation.If it is not cheated ever program sends current data(cheated or not).
i marked where i changed with *.
You need to putBoolean before callback the super method.
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
savedInstanceState.putBoolean(CHEATER,mIsCheater);
super.onSaveInstanceState(savedInstanceState);
}
if not the CHEATER won't be saved and you can't call it when resume activity