How to Implement timing and countdown in Android

Method 1

Timer and TimerTask (Java implementation)

Public class timerTask extends Activity {</p> <p> private int recLen = 11; <br/> private TextView txtView; <br/> Timer timer = new Timer (); </p> <p> public void onCreate (Bundle savedInstanceState) {<br/> super. onCreate (savedInstanceState); </p> <p> setContentView (R. layout. timertask); <br/> txtView = (textview1_findviewbyid(r.id.txt time); </p> <p> timer. schedule (task, 1000,100 0); // timeTask <br/>}</p> <p> TimerTask task = new TimerTask () {<br/> @ Override <br/> public void run () {</p> <p> runOnUiThread (new Runnable () {// UI thread <br/> @ Override <br/> public void run () {<br/> recLen --; <br/> txtView. setText ("" + recLen); <br/> if (recLen <0) {<br/> timer. cancel (); <br/> txtView. setVisibility (View. GONE); <br/>}< br/>}); <br/>}< br/>}; <br/>}

Method 2

TimerTask and Handler (without the improved Timer)

Public class timerTask extends Activity {<br/> private int recLen = 11; <br/> private TextView txtView; <br/> Timer timer = new Timer (); </p> <p> public void onCreate (Bundle savedInstanceState) {<br/> super. onCreate (savedInstanceState); </p> <p> setContentView (R. layout. timertask); <br/> txtView = (textview1_findviewbyid(r.id.txt time); </p> <p> timer. schedule (task, 1000,100 0); // timeTask <br/>}</p> <p> final Handler handler = new Handler () {<br/> @ Override <br/> public void handleMessage (Message msg) {<br/> switch (msg. what) {<br/> case 1: <br/> txtView. setText ("" + recLen); <br/> if (recLen <0) {<br/> timer. cancel (); <br/> txtView. setVisibility (View. GONE); <br/>}< br/>}; </p> <p> TimerTask task = new TimerTask () {<br/> @ Override <br/> public void run () {<br/> recLen --; <br/> Message message = new Message (); <br/> message. what = 1; <br/> handler. sendMessage (message); <br/>}< br/>}; <br/>}
Method 3

Handler and Message (without TimerTask)

Public class timerTask extends Activity {<br/> private int recLen = 11; <br/> private TextView txtView; </p> <p> public void onCreate (Bundle savedInstanceState) {<br/> super. onCreate (savedInstanceState); </p> <p> setContentView (R. layout. timertask); <br/> txtView = (textview1_findviewbyid(r.id.txt time); </p> <p> Message message = handler. obtainMessage (1); // Message <br/> handler. sendMessageDelayed (message, 1000); <br/>}</p> <p> final Handler handler = new Handler () {</p> <p> public void handleMessage (Message msg) {// handle message <br/> switch (msg. what) {<br/> case 1: <br/> recLen --; <br/> txtView. setText ("" + recLen); </p> <p> if (recLen> 0) {<br/> Message message = handler. obtainMessage (1); <br/> handler. sendMessageDelayed (message, 1000); // send message <br/>}else {<br/> txtView. setVisibility (View. GONE); <br/>}</p> <p> super. handleMessage (msg); <br/>}< br/>}; <br/>}
Method 4

Handler and Thread (do not occupy the UI Thread)

Public class timerTask extends Activity {<br/> private int recLen = 0; <br/> private TextView txtView; </p> <p> public void onCreate (Bundle savedInstanceState) {<br/> super. onCreate (savedInstanceState); </p> <p> setContentView (R. layout. timertask); <br/> txtView = (textview1_findviewbyid(r.id.txt time); </p> <p> new Thread (new MyThread ()). start (); // start thread <br/>}</p> <p> final Handler handler = new Handler () {// handle <br/> public void handleMessage (Message msg) {<br/> switch (msg. what) {<br/> case 1: <br/> recLen ++; <br/> txtView. setText ("" + recLen); <br/>}< br/> super. handleMessage (msg); <br/>}< br/> }; </p> <p> public class MyThread implements Runnable {// thread <br/> @ Override <br/> public void run () {<br/> while (true) {<br/> try {<br/> Thread. sleep (1000); // sleep 1000 ms <br/> Message message = new Message (); <br/> message. what = 1; <br/> handler. sendMessage (message); <br/>} catch (Exception e) {<br/>}< br/>}
Method 5

Handler and Runnable (simplest type)

Public class timerTask extends Activity {<br/> private int recLen = 0; <br/> private TextView txtView; </p> <p> public void onCreate (Bundle savedInstanceState) {<br/> super. onCreate (savedInstanceState); </p> <p> setContentView (R. layout. timertask); <br/> txtView = (textview1_findviewbyid(r.id.txt time); </p> <p> handler. postDelayed (runnable, 1000); <br/>}</p> <p> Handler handler = new Handler (); <br/> Runnable runnable = new Runnable () {<br/> @ Override <br/> public void run () {<br/> recLen ++; <br/> txtView. setText ("" + recLen); <br/> handler. postDelayed (this, 1000); <br/>}< br/>}; <br/>}

Timing and countdown

Method 1, method 2, and method 3 are all countdown

Method 4 and Method 5 are all timing

Both timing and countdown can be implemented using the above method (slightly changed code)

UI thread comparison

Method 1, method 2, and method 3 are all timing implemented in the UI thread;

Method 4 and Method 5 are separate Runnable threads for timing.

Comparison of implementation methods

Method 1 adopts Java implementation, namely, Timer and TimerTask;

Handler message processing is used in the other four methods.

Recommended

If you do not have high requirements on UI thread interaction, you can select methods 2 and 3.

If the UI thread blocking seriously affects the user experience, Method 4 is recommended. Another thread is used separately for timing and other logic processing.

Method 5, combining the advantages of the previous methods, is the simplest