android 倒计时的几种做法

傷城~ 2022-08-06 11:18 200阅读 0赞

[1. CountDownTimer][] 是android 自己封装的定时，倒计时的类

主要是重写onTick和onFinsh这两个方法，onFinish()中的代码是计时器结束的时候要做的事情；onTick(Long m)中的代码是你倒计时开始时要做的事情，参数m是直到完成的时间，构造方法MyCount()中的两个参数中，前者是倒计的时间数，后者是倒计每秒中间 的间隔时间，都是以毫秒为单位。例如要倒计时30秒，每秒中间间隔时间是1秒，两个参数可以这样写MyCount(30000,1000)。 将后台线程的创建和Handler队列封装成为了一个方便的类调用。

当你想取消的时候使用mc.cancel()方法就行了

package cn.demo;

import android.app.Activity;  
import android.os.Bundle;  
import android.content.Intent;  
import android.os.[CountDownTimer][1. CountDownTimer];  
import android.widget.TextView;  
import android.widget.Toast;  
public class NewActivity extends Activity \{  
private MyCount mc;  
private TextView tv;  
@Override  
protected void onCreate(Bundle savedInstanceState) \{  
// TODO Auto-generated method stub  
super.onCreate(savedInstanceState);  
setContentView(R.layout.main);  
tv = (TextView)findViewById(R.id.show);  
mc = new MyCount(30000, 1000);  
mc.start();  
\}//end func

/\*定义一个倒计时的内部类\*/  
class MyCount extends [CountDownTimer][1. CountDownTimer] \{  
public MyCount(long millisInFuture, long countDownInterval) \{  
super(millisInFuture, countDownInterval);  
\}  
@Override  
public void onFinish() \{  
tv.setText("finish");  
\}  
@Override  
public void onTick(long millisUntilFinished) \{  
tv.setText("请等待30秒(" + millisUntilFinished / 1000 + ")...");  
Toast.makeText(NewActivity.this, millisUntilFinished / 1000 + "", Toast.LENGTH\_LONG).show();//toast有显示时间延迟  
\}  
\}  
\}

2.  
Handler与Runnable

package com.android.settings;  
  
import java.util.ArrayList;  
  
import com.android.settings.location.RadioButtonPreference;  
import com.android.settings.location.RadioButtonPreference.OnClickListener;  
  
import android.content.ContentResolver;  
import android.location.LocationManager;  
import android.os.Bundle;  
import android.os.Handler;  
import android.preference.CheckBoxPreference;  
import android.preference.Preference;  
import android.preference.Preference.OnPreferenceChangeListener;  
import android.preference.Preference.OnPreferenceClickListener;  
import android.preference.PreferenceActivity;  
import android.preference.PreferenceCategory;  
import android.preference.PreferenceScreen;  
import android.provider.Settings;  
import android.util.Log;  
import android.widget.Toast;  
  
public class BeidouDetailSettingsActivity extends PreferenceActivity implements  
OnPreferenceClickListener \{  
  
private RadioButtonPreference mSelectGpsMode;  
  
private RadioButtonPreference mSelectBeidouMode;  
  
private RadioButtonPreference mSelectMixMode;  
  
private CheckBoxPreference mPowerSaveMode;  
  
private static final String GPS\_MODE = "gps\_mode";  
private static final String BEIDOU\_MODE = "beidou\_mode";  
private static final String MIX\_MODE = "mix\_mode";  
  
private static final String TAG = "BeidouDetailSettingsActivity";  
private static String KEY1\_WORK\_SAVE\_MODE = "gps\_power\_save\_mode";  
  
private int recLen;  
  
@Override  
protected void onCreate(Bundle savedInstanceState) \{  
super.onCreate(savedInstanceState);  
  
handler.postDelayed(runnable, 1000);  
\}  
  
@Override  
protected void onResume() \{  
super.onResume();  
createPreferenceHierarchy();  
updateLocationToggles();  
\}  
  
private void updateLocationToggles() \{  
// TODO Auto-generated method stub  
  
int mode = Settings.Secure.getInt(getContentResolver(),  
Settings.Secure.BEIDOU\_NAVIGATION\_MODE, -1);  
  
int saveMode = Settings.Secure.getInt(getContentResolver(),  
Settings.Secure.GPS\_POWER\_SAVING\_MODE, -1);  
  
if (saveMode == 1) \{  
mPowerSaveMode.setChecked(true);  
\} else \{  
mPowerSaveMode.setChecked(false);  
\}  
if (mode == 0) \{  
  
mSelectGpsMode.setChecked(false);  
mSelectBeidouMode.setChecked(true);  
mSelectMixMode.setChecked(false);  
  
\} else if (mode == 1) \{  
  
mSelectGpsMode.setChecked(true);  
mSelectBeidouMode.setChecked(false);  
mSelectMixMode.setChecked(false);  
  
\} else \{  
mSelectGpsMode.setChecked(false);  
mSelectBeidouMode.setChecked(false);  
mSelectMixMode.setChecked(true);  
\}  
\}  
  
private PreferenceScreen createPreferenceHierarchy() \{  
  
PreferenceScreen root = getPreferenceScreen();  
if (root != null) \{  
root.removeAll();  
\}  
addPreferencesFromResource(R.xml.beidou\_detail\_preference\_settings);  
root = getPreferenceScreen();  
  
/\*\*  
\* add by xuhong.tian  
\*/  
mPowerSaveMode = (CheckBoxPreference) root  
.findPreference(KEY1\_WORK\_SAVE\_MODE);  
mSelectGpsMode = (RadioButtonPreference) root.findPreference(GPS\_MODE);  
mSelectBeidouMode = (RadioButtonPreference) root  
.findPreference(BEIDOU\_MODE);  
mSelectMixMode = (RadioButtonPreference) root.findPreference(MIX\_MODE);  
mPowerSaveMode.setOnPreferenceClickListener(this);  
mSelectMixMode.setOnPreferenceClickListener(this);  
mSelectBeidouMode.setOnPreferenceClickListener(this);  
mSelectGpsMode.setOnPreferenceClickListener(this);  
  
return root;  
\}  
  
@Override  
public boolean onPreferenceClick(Preference preference) \{  
// TODO Auto-generated method stub  
Log.d(TAG, "preference==" + preference);  
  
if (preference == null) \{  
mSelectGpsMode.setChecked(false);  
mSelectBeidouMode.setChecked(false);  
mSelectMixMode.setChecked(false);  
return true;  
\} else if (preference == mSelectGpsMode) \{  
mSelectGpsMode.setChecked(true);  
mSelectBeidouMode.setChecked(false);  
mSelectMixMode.setChecked(false);  
  
Settings.Secure.putInt(getContentResolver(),  
Settings.Secure.BEIDOU\_NAVIGATION\_MODE, 1);  
return true;  
\} else if (preference == mSelectBeidouMode) \{  
mSelectGpsMode.setChecked(false);  
mSelectBeidouMode.setChecked(true);  
mSelectMixMode.setChecked(false);  
  
Settings.Secure.putInt(getContentResolver(),  
Settings.Secure.BEIDOU\_NAVIGATION\_MODE, 0);  
return true;  
\} else if (preference == mSelectMixMode) \{  
mSelectGpsMode.setChecked(false);  
mSelectBeidouMode.setChecked(false);  
mSelectMixMode.setChecked(true);  
  
Settings.Secure.putInt(getContentResolver(),  
Settings.Secure.BEIDOU\_NAVIGATION\_MODE, 2);  
return true;  
\} else if (preference == mPowerSaveMode) \{  
if (mPowerSaveMode.isChecked()) \{  
  
Settings.Secure.putInt(getContentResolver(),  
Settings.Secure.GPS\_POWER\_SAVING\_MODE, 1);  
return true;  
\} else \{  
  
Settings.Secure.putInt(getContentResolver(),  
Settings.Secure.GPS\_POWER\_SAVING\_MODE, 0);  
return true;  
\}  
\}  
return false;  
\}  
  
Handler handler = new Handler();  
Runnable runnable = new Runnable() \{  
  
@Override  
public void run() \{  
recLen++;  
mSelectMixMode.setSummaryOn(String.valueOf(recLen));  
// handler.postDelayed(this, 1000);  
\}  
\};  
\}Handler与Thread（不占用UI线程）

1.  public class timerTask extends Activity\{
2.  private int recLen = 0;
3.  private TextView txtView;
4.  
5.  public void onCreate(Bundle savedInstanceState)\{
6.  super.onCreate(savedInstanceState);
7.  
8.  setContentView(R.layout.timertask);
9.  txtView = (TextView)findViewById(R.id.txttime);
10. 
11. new Thread(new MyThread()).start(); // start thread
12. \}
13. 
14. final Handler handler = new Handler()\{ // handle
15. public void handleMessage(Message msg)\{
16. switch (msg.what) \{
17. case 1:
18. recLen++;
19. txtView.setText("" \+ recLen);
20. \}
21. super.handleMessage(msg);
22. \}
23. \};
24. 
25. public class MyThread implements Runnable\{ // thread
26. @Override
27. public void run()\{
28. while(true)\{
29. try\{
30. Thread.sleep(1000); // sleep 1000ms
31. Message message = new Message();
32. message.what = 1;
33. handler.sendMessage(message);
34. \}catch (Exception e) \{
35. \}
36. \}
37. \}
38. \}
39. \}

[1. CountDownTimer]: http://www.mythroad.net/tag/countdowntimer/