Android计时器？如何？

概述有人可以给出一个每秒钟更新文本字段的简单示例吗？我想做一个飞球,需要每秒计算/更新球坐标,这就是我需要某种计时器的原因.我从here没有得到任何东西.解决方法:好吧,因为这还没有解决,有3种简单的方法来处理这个问题.下面是一个示例,显示所有3和底部是一个示例,显示我认为更可取

有人可以给出一个每秒钟更新文本字段的简单示例吗？

我想做一个飞球,需要每秒计算/更新球坐标,这就是我需要某种计时器的原因.

我从here没有得到任何东西.

解决方法:

好吧,因为这还没有解决,有3种简单的方法来处理这个问题.
下面是一个示例,显示所有3和底部是一个示例,显示我认为更可取的方法.还记得在onPause中清理你的任务,必要时保存状态.

import java.util.Timer;import java.util.TimerTask;import androID.app.Activity;import androID.os.Bundle;import androID.os.Handler;import androID.os.Message;import androID.os.Handler.Callback;import androID.vIEw.VIEw;import androID.Widget.button;import androID.Widget.TextVIEw;public class main extends Activity {    TextVIEw text, text2, text3;    long starttime = 0;    //this  posts a message to the main thread from our timertask    //and updates the textfIEld   final Handler h = new Handler(new Callback() {        @OverrIDe        public boolean handleMessage(Message msg) {           long millis = System.currentTimeMillis() - starttime;           int seconds = (int) (millis / 1000);           int minutes = seconds / 60;           seconds     = seconds % 60;           text.setText(String.format("%d:%02d", minutes, seconds));            return false;        }    });   //runs without timer be reposting self   Handler h2 = new Handler();   Runnable run = new Runnable() {        @OverrIDe        public voID run() {           long millis = System.currentTimeMillis() - starttime;           int seconds = (int) (millis / 1000);           int minutes = seconds / 60;           seconds     = seconds % 60;           text3.setText(String.format("%d:%02d", minutes, seconds));           h2.postDelayed(this, 500);        }    };   //tells handler to send a message   class firstTask extends TimerTask {        @OverrIDe        public voID run() {            h.sendEmptyMessage(0);        }   };   //tells activity to run on ui thread   class secondTask extends TimerTask {        @OverrIDe        public voID run() {            main.this.runOnUiThread(new Runnable() {                @OverrIDe                public voID run() {                   long millis = System.currentTimeMillis() - starttime;                   int seconds = (int) (millis / 1000);                   int minutes = seconds / 60;                   seconds     = seconds % 60;                   text2.setText(String.format("%d:%02d", minutes, seconds));                }            });        }   };   Timer timer = new Timer();    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.main);        text = (TextVIEw)findVIEwByID(R.ID.text);        text2 = (TextVIEw)findVIEwByID(R.ID.text2);        text3 = (TextVIEw)findVIEwByID(R.ID.text3);        button b = (button)findVIEwByID(R.ID.button);        b.setText("start");        b.setonClickListener(new VIEw.OnClickListener() {            @OverrIDe            public voID onClick(VIEw v) {                button b = (button)v;                if(b.getText().equals("stop")){                    timer.cancel();                    timer.purge();                    h2.removeCallbacks(run);                    b.setText("start");                }else{                    starttime = System.currentTimeMillis();                    timer = new Timer();                    timer.schedule(new firstTask(), 0,500);                    timer.schedule(new secondTask(),  0,500);                    h2.postDelayed(run, 0);                    b.setText("stop");                }            }        });    }    @OverrIDe    public voID onPause() {        super.onPause();        timer.cancel();        timer.purge();        h2.removeCallbacks(run);        button b = (button)findVIEwByID(R.ID.button);        b.setText("start");    }}

要记住的主要事情是UI只能从主ui线程修改,所以使用处理程序或activity.runOnUIThread(Runnable r);

这是我认为首选的方法.

import androID.app.Activity;import androID.os.Bundle;import androID.os.Handler;import androID.vIEw.VIEw;import androID.Widget.button;import androID.Widget.TextVIEw;public class TestActivity extends Activity {    TextVIEw timerTextVIEw;    long startTime = 0;    //runs without a timer by reposting this handler at the end of the runnable    Handler timerHandler = new Handler();    Runnable timerRunnable = new Runnable() {        @OverrIDe        public voID run() {            long millis = System.currentTimeMillis() - startTime;            int seconds = (int) (millis / 1000);            int minutes = seconds / 60;            seconds = seconds % 60;            timerTextVIEw.setText(String.format("%d:%02d", minutes, seconds));            timerHandler.postDelayed(this, 500);        }    };    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.test_activity);        timerTextVIEw = (TextVIEw) findVIEwByID(R.ID.timerTextVIEw);        button b = (button) findVIEwByID(R.ID.button);        b.setText("start");        b.setonClickListener(new VIEw.OnClickListener() {            @OverrIDe            public voID onClick(VIEw v) {                button b = (button) v;                if (b.getText().equals("stop")) {                    timerHandler.removeCallbacks(timerRunnable);                    b.setText("start");                } else {                    startTime = System.currentTimeMillis();                    timerHandler.postDelayed(timerRunnable, 0);                    b.setText("stop");                }            }        });    }  @OverrIDe    public voID onPause() {        super.onPause();        timerHandler.removeCallbacks(timerRunnable);        button b = (button)findVIEwByID(R.ID.button);        b.setText("start");    }}

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