Android實現計時與倒計時的幾種方法

Android實現計時與倒計時的五種方法：

方法一

Timer與TimerTask（Java實現）

1. public class timerTask extends Activity{
3. private int recLen = 11;
4. private TextView txtView;
5. Timer timer = new Timer();
7. public void onCreate(Bundle savedInstanceState){
8. super.onCreate(savedInstanceState);
10. setContentView(R.layout.timertask);
11. txtView = (TextView)findViewById(R.id.txttime);
13. timer.schedule(task, 1000, 1000); // timeTask
14. }
16. TimerTask task = new TimerTask() {
17. @Override
18. public void run() {
20. runOnUiThread(new Runnable() { // UI thread
21. @Override
22. public void run() {
23. recLen--;
24. txtView.setText(""+recLen);
25. if(recLen < 0){
26. timer.cancel();
27. txtView.setVisibility(View.GONE);
28. }
29. }
30. });
31. }
32. };
33. }

方法二

TimerTask與Handler（不用Timer的改進型）

1. public class timerTask extends Activity{
2. private int recLen = 11;
3. private TextView txtView;
4. Timer timer = new Timer();
6. public void onCreate(Bundle savedInstanceState){
7. super.onCreate(savedInstanceState);
9. setContentView(R.layout.timertask);
10. txtView = (TextView)findViewById(R.id.txttime);
12. timer.schedule(task, 1000, 1000); // timeTask
13. }
15. final Handler handler = new Handler(){
16. @Override
17. public void handleMessage(Message msg){
18. switch (msg.what) {
19. case 1:
20. txtView.setText(""+recLen);
21. if(recLen < 0){
22. timer.cancel();
23. txtView.setVisibility(View.GONE);
24. }
25. }
26. }
27. };
29. TimerTask task = new TimerTask() {
30. @Override
31. public void run() {
32. recLen--;
33. Message message = new Message();
34. message.what = 1;
35. handler.sendMessage(message);
36. }
37. };
38. }

Handler與Message（不用TimerTask）

1. public class timerTask extends Activity{
2. private int recLen = 11;
3. private TextView txtView;
5. public void onCreate(Bundle savedInstanceState) {
6. super.onCreate(savedInstanceState);
8. setContentView(R.layout.timertask);
9. txtView = (TextView)findViewById(R.id.txttime);
11. Message message = handler.obtainMessage(1); // Message
12. handler.sendMessageDelayed(message, 1000);
13. }
15. final Handler handler = new Handler(){
17. public void handleMessage(Message msg){ // handle message
18. switch (msg.what) {
19. case 1:
20. recLen--;
21. txtView.setText("" + recLen);
23. if(recLen > 0){
24. Message message = handler.obtainMessage(1);
25. handler.sendMessageDelayed(message, 1000); // send message
26. }else{
27. txtView.setVisibility(View.GONE);
28. }
29. }
31. super.handleMessage(msg);
32. }
33. };
34. }