Android 入门经典——编写Android计时器程序

package com.zkzhang.android.time; import java.util.TimerTask; import android.app.Activity; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.content.SharedPreferences; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.KeyEvent; import android.view.Menu; import android.view.MenuItem; import android.view.SubMenu; import android.view.View; import android.widget.ImageButton; import android.widget.TextView; public class Timer extends Activity { private long mlCount = 0; private long mlTimerUnit = 100; private TextView tvTime; private ImageButton btnStartPause; private ImageButton btnStop; private Timer timer = null; private TimerTask task = null; private Handler handler = null; private Message msg = null; private boolean bIsRunningFlg = false; private static final String MYTIMER_TAG = "MYTIMER_LOG"; // menu item private static final int SETTING_TIMER_UNIT_ID = Menu.FIRST; private static final int ABOUT_ID = Menu.FIRST + 1; private static final int EXIT_ID = Menu.FIRST + 2; private static final int SETTING_SECOND_ID = Menu.FIRST + 101; private static final int SETTING_100MILLISECOND_ID = Menu.FIRST + 102; // Setting timer unit flag private int settingTimerUnitFlg = SETTING_100MILLISECOND_ID; public Timer(boolean b) { // TODO Auto-generated constructor stub } /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tvTime = (TextView)findViewById(R.id.tvTime); btnStartPause = (ImageButton)findViewById(R.id.btnStartPaunse); btnStop = (ImageButton)findViewById(R.id.btnStop); SharedPreferences sharedPreferences = getSharedPreferences("mytimer_unit", Context.MODE_PRIVATE); //getString()第二个参数为缺省值，如果preference中不存在该key，将返回缺省值 mlTimerUnit = sharedPreferences.getLong("time_unit", 100); Log.i(MYTIMER_TAG, "mlTimerUnit = " + mlTimerUnit); if (1000 == mlTimerUnit) { // second settingTimerUnitFlg = SETTING_SECOND_ID; tvTime.setText(R.string.init_time_second); } else if (100 == mlTimerUnit) { // 100 millisecond settingTimerUnitFlg = SETTING_100MILLISECOND_ID; tvTime.setText(R.string.init_time_100millisecond); } // Handle timer message handler = new Handler(){ @Override public void handleMessage(Message msg) { // TODO Auto-generated method stub switch(msg.what) { case 1: mlCount++; int totalSec = 0; int yushu = 0; if (SETTING_SECOND_ID == settingTimerUnitFlg) { // second totalSec = (int)(mlCount); } else if (SETTING_100MILLISECOND_ID == settingTimerUnitFlg) { // 100 millisecond totalSec = (int)(mlCount / 10); yushu = (int)(mlCount % 10); } // Set time display int min = (totalSec / 60); int sec = (totalSec % 60); try{ if (SETTING_SECOND_ID == settingTimerUnitFlg) { // second(1000ms) tvTime.setText(String.format("%1$02d:%2$02d", min, sec)); } else if (SETTING_100MILLISECOND_ID == settingTimerUnitFlg) { // 100 millisecond tvTime.setText(String.format("%1$02d:%2$02d:%3$d", min, sec, yushu)); } } catch(Exception e) { tvTime.setText("" + min + ":" + sec + ":" + yushu); e.printStackTrace(); Log.e("MyTimer onCreate", "Format string error."); } break; default: break; } super.handleMessage(msg); } }; btnStartPause.setOnClickListener(startPauseListener); btnStop.setOnClickListener(stopListener); } // Start and pause View.OnClickListener startPauseListener = new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Log.i(MYTIMER_TAG, "Start/Pause is clicked."); if (null == timer) { if (null == task) { task = new TimerTask() { @Override public void run() { // TODO Auto-generated method stub if (null == msg) { msg = new Message(); } else { msg = Message.obtain(); } msg.what = 1; handler.sendMessage(msg); } }; } timer = new Timer(true); timer.schedule(task, mlTimerUnit, mlTimerUnit); // set timer duration } // start if (!bIsRunningFlg) { bIsRunningFlg = true; btnStartPause.setImageResource(R.drawable.pause); } else { // pause try{ bIsRunningFlg = false; task.cancel(); task = null; timer.cancel(); // Cancel timer timer.purge(); timer = null; handler.removeMessages(msg.what); btnStartPause.setImageResource(R.drawable.start); } catch(Exception e) { e.printStackTrace(); } } } }; // Stop View.OnClickListener stopListener = new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Log.i(MYTIMER_TAG, "Stop is clicked."); if (null != timer) { task.cancel(); task = null; timer.cancel(); // Cancel timer timer.purge(); timer = null; handler.removeMessages(msg.what); } mlCount = 0; bIsRunningFlg = false; btnStartPause.setImageResource(R.drawable.start); if (SETTING_SECOND_ID == settingTimerUnitFlg) { // second tvTime.setText(R.string.init_time_secon