StopWatch Android App Project - Part 3
This the final part in our series of making a Stopwatch Android App in android studio and this is one of the most important part in this project.
If you haven't followed the previous two parts, please do before going forward with this:
In this part we will write the login for all the features of stopwatch to make the app work according to our needs. So before going to the coding part we have to know some basic things as shown below:
-
1 second = 1000 millisecond
-
1 minute = 60 second
-
1 hour =60 minute
Stopwatch Android App - Code the Logic
Now open the MainActivity.java file and import some basic classes as shown below:
//importing required classes
import android.os.Handler;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Locale;
Next we create the object of Android ImageView and Android Textview inside MainActivity class as shown below:
//creating object of ImageView and Text View
ImageView playBtn, pauseBtn, stopBtn, timeLapseBtn;
TextView timeView;
TextView timeViewms;
TextView timeLapse;
Next we add come integer variable and boolean variable as ashow below inside MainActivity.java class:
// integers to store hours, minutes, seconds, ms
int hours, minutes, secs, ms;
// integer to store seconds
private int seconds = 0;
// boolean to check if the stopwatch is running or not
private boolean running;
// simple count variable to count number of laps
int lapCount=0;
Now inside the onCreate method we initialize the ImageView and TextView and add the OnClickListener and show a simple Android Toast message to the user according to the input as shown below:
// initializing the Image view objects
playBtn=(ImageView)findViewById(R.id.playBtn) ;
pauseBtn=(ImageView)findViewById(R.id.pauseBtn) ;
stopBtn=(ImageView)findViewById(R.id.stopBtn) ;
timeLapseBtn=(ImageView)findViewById(R.id.timeLapseBtn) ;
// initializing the text view objects
timeView = (TextView)findViewById(R.id.time_view) ;
timeViewms=(TextView)findViewById(R.id.time_view_ms) ;
timeLapse = (TextView)findViewById(R.id.timeLapse) ;
// play button click listener
playBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Started", Toast.LENGTH_SHORT).show();
// hide the play and stop button
playBtn.setVisibility(View.GONE) ;
stopBtn.setVisibility(View.GONE) ;
// show the pause and time lapse button
pauseBtn.setVisibility(View.VISIBLE) ;
timeLapseBtn.setVisibility(View.VISIBLE) ;
// set running true
running = true ;
}
}) ;
// pause button click listener
pauseBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Paused", Toast.LENGTH_SHORT).show();
// show the play and stop button
playBtn.setVisibility(View.VISIBLE) ;
stopBtn.setVisibility(View.VISIBLE) ;
// hide the pause and time lapse button
timeLapseBtn.setVisibility(View.GONE) ;
pauseBtn.setVisibility(View.GONE) ;
running = false ;
}
}) ;
// stop button click listener
stopBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Stoped", Toast.LENGTH_SHORT).show();
// set running to false
running = false ;
seconds = 0 ;
lapCount=0 ;
// setting the text view to zero
timeView.setText("00:00:00") ;
timeViewms.setText("00") ;
timeLapse.setText("") ;
// show the play
playBtn.setVisibility(View.VISIBLE) ;
// hide the pause , stop and time lapse button
pauseBtn.setVisibility(View.GONE) ;
stopBtn.setVisibility(View.GONE) ;
timeLapseBtn.setVisibility(View.GONE) ;
}
}) ;
// lap button click listener
timeLapseBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// calling timeLapse function
timeLapseFun() ;
}
}) ;
// calling runtimer
runTimer() ;
Now inside create a method private void runTimer which is called when we click the start button as shown below:
private void runTimer() {
// creating handler
final Handler handlertime = new Handler();
// creating handler
final Handler handlerMs = new Handler();
handlertime.post(new Runnable() {@Override
public void run() {
hours = seconds / 3600;
minutes = (seconds % 3600) / 60;
secs = seconds % 60;
// if running increment the seconds
if (running) {
String time = String.format(Locale.getDefault(), "%02d:%02d:%02d", hours, minutes, secs);
timeView.setText(time);
seconds++;
}
handlertime.postDelayed(this, 1000);
}
});
handlerMs.post(new Runnable() {@Override
public void run() {
if (ms >= 99) {
ms = 0;
}
// if running increment the ms
if (running) {
String msString = String.format(Locale.getDefault(), "%02d", ms);
timeViewms.setText(msString);
ms++;
}
handlerMs.postDelayed(this, 1);
}
});
}
We create one more method inside the MainActivity.java to handle lap time as shown below:
void timeLapseFun() {
// increase lap count when function is called
lapCount++;
String laptext = String.format(Locale.getDefault(), "%02d:%02d:%02d", hours, minutes, secs);
String msString = String.format(Locale.getDefault(), "%02d", ms);
// adding ms to lap text
laptext = laptext + ":" + msString;
if (lapCount >= 10) {
laptext = " Lap " + lapCount + " -------------> " + laptext + " \n " + timeLapse.getText();
} else {
laptext = " Lap " + lapCount + " ---------------> " + laptext + " \n " + timeLapse.getText();
}
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Lap " + lapCount, Toast.LENGTH_SHORT).show();
// showing the lap text
timeLapse.setText(laptext);
}
The complete code of the MainActivity.java is shown below:
package com.studytonight.project;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
// importing required classes
import android.os.Handler;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
// integers to store hours , minutes , seconds , ms
int hours,
minutes,
secs,
ms;
// integer to store seconds
private int seconds = 0;
// boolean to check if stopwatch is running or not
private boolean running;
// simple count variable to count number of laps
int lapCount = 0;
// creating object of ImageView and Text View
ImageView playBtn,
pauseBtn,
stopBtn,
timeLapseBtn;
TextView timeView;
TextView timeViewms;
TextView timeLapse;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// initializing the Image view objects
playBtn = (ImageView) findViewById(R.id.playBtn);
pauseBtn = (ImageView) findViewById(R.id.pauseBtn);
stopBtn = (ImageView) findViewById(R.id.stopBtn);
timeLapseBtn = (ImageView) findViewById(R.id.timeLapseBtn);
// initializing the text view objects
timeView = (TextView) findViewById(R.id.time_view);
timeViewms = (TextView) findViewById(R.id.time_view_ms);
timeLapse = (TextView) findViewById(R.id.timeLapse);
// play button click listener
playBtn.setOnClickListener(new View.OnClickListener() {@Override
public void onClick(View view) {
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Started", Toast.LENGTH_SHORT).show();
// hide the play and stop button
playBtn.setVisibility(View.GONE);
stopBtn.setVisibility(View.GONE);
// show the pause and time lapse button
pauseBtn.setVisibility(View.VISIBLE);
timeLapseBtn.setVisibility(View.VISIBLE);
// set running true
running = true;
}
});
// pause button click listener
pauseBtn.setOnClickListener(new View.OnClickListener() {@Override
public void onClick(View view) {
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Paused", Toast.LENGTH_SHORT).show();
// show the play and stop button
playBtn.setVisibility(View.VISIBLE);
stopBtn.setVisibility(View.VISIBLE);
// hide the pause and time lapse button
timeLapseBtn.setVisibility(View.GONE);
pauseBtn.setVisibility(View.GONE);
running = false;
}
});
// stop button click listener
stopBtn.setOnClickListener(new View.OnClickListener() {@Override
public void onClick(View view) {
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Stoped", Toast.LENGTH_SHORT).show();
// set running to false
running = false;
seconds = 0;
lapCount = 0;
// setting the text view to zero
timeView.setText("00:00:00");
timeViewms.setText("00");
timeLapse.setText("");
// show the play
playBtn.setVisibility(View.VISIBLE);
// hide the pause , stop and time lapse button
pauseBtn.setVisibility(View.GONE);
stopBtn.setVisibility(View.GONE);
timeLapseBtn.setVisibility(View.GONE);
}
});
// lap button click listener
timeLapseBtn.setOnClickListener(new View.OnClickListener() {@Override
public void onClick(View view) {
// calling timeLapse function
timeLapseFun();
}
});
// calling runtimer
runTimer();
}
private void runTimer() {
// creating handler
final Handler handlertime = new Handler();
// creating handler
final Handler handlerMs = new Handler();
handlertime.post(new Runnable() {@Override
public void run() {
hours = seconds / 3600;
minutes = (seconds % 3600) / 60;
secs = seconds % 60;
// if running increment the seconds
if (running) {
String time = String.format(Locale.getDefault(), "%02d:%02d:%02d", hours, minutes, secs);
timeView.setText(time);
seconds++;
}
handlertime.postDelayed(this, 1000);
}
});
handlerMs.post(new Runnable() {@Override
public void run() {
if (ms >= 99) {
ms = 0;
}
// if running increment the ms
if (running) {
String msString = String.format(Locale.getDefault(), "%02d", ms);
timeViewms.setText(msString);
ms++;
}
handlerMs.postDelayed(this, 1);
}
});
}
void timeLapseFun() {
// increase lap count when function is called
lapCount++;
String laptext = String.format(Locale.getDefault(), "%02d:%02d:%02d", hours, minutes, secs);
String msString = String.format(Locale.getDefault(), "%02d", ms);
// adding ms to lap text
laptext = laptext + ":" + msString;
if (lapCount >= 10) {
laptext = " Lap " + lapCount + " -------------> " + laptext + " \n " + timeLapse.getText();
} else {
laptext = " Lap " + lapCount + " ---------------> " + laptext + " \n " + timeLapse.getText();
}
//showing simple toast message to user
Toast.makeText(MainActivity.this, "Lap " + lapCount, Toast.LENGTH_SHORT).show();
// showing the lap text
timeLapse.setText(laptext);
}
}
Output:
In the below snapshots, you can see how the Stopwatch will look in the android application.
When App is opened first time:
When we click on start:
When we click the pause:
When we click on lap icon (we have recorded 12 laps)
When we click on stop icon:
Conclusion:
And with this we have successfully completed the Stopwatch project. If this project helped you then find us on Instagram - @study.tonight and share with us snapshots of your project. Congratulations on finishing the project.
