Android实现计时以及倒计时的几种方法

来源：互联网发布：java中的注释编辑：程序博客网时间：2024/06/16 12:13

方法1:
Timer与TimerTask（Java实现）

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

方法2:
TimerTask与Handler（不用Timer的改进型）

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

方法3:
Handler与Message（不用TimerTask）

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

方法4:
Handler与Thread（不占用UI线程）

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

方法5:
Handler与Runnable(最简单型)

public class timerTask extends Activity{        private int recLen = 0;        private TextView txtView;        public void onCreate(Bundle savedInstanceState){            super.onCreate(savedInstanceState);            setContentView(R.layout.timertask);            txtView = (TextView)findViewById(R.id.txttime);            handler.postDelayed(runnable, 1000);        }           Handler handler = new Handler();        Runnable runnable = new Runnable() {            @Override            public void run() {                recLen++;                txtView.setText("" + recLen);                handler.postDelayed(this, 1000);            }        };    }

计时与倒计时
方法1，方法2和方法3，都是倒计时
方法4，方法5，都是计时
计时和倒计时，都可使用上述方法实现（代码稍加改动）

UI线程比较
方法1，方法2和方法3，都是在UI线程实现的计时；
方法4和方法5，是另开Runnable线程实现计时

实现方式比较
方法1，采用的是Java实现，即Timer和TimerTask方式；
其它四种方法，都采用了Handler消息处理

推荐使用
如果对UI线程交互要求不很高，可以选择方法2和方法3
如果考虑到UI线程阻塞，严重影响到用户体验，推荐使用方法4，另起线程单独用于计时和其它的逻辑处理
方法5，综合了前几种方法的优点，是最简的

2 0