android 时钟开发



一、开发手机闹钟主要用到了AlarmManager类，AlarmManager类提供了访问系统定时服务的途径，开发人员可以在程序中设置某个应用程序在未来的某个时刻被执行。当AlarmManager定时时间到了之后，当初注册的Intent对象将会被系统广播，进而启动目标程序。

二、在程序运行时当需要使用AlarmManager类时，可以通过Context对象的getSystemService(Context.ALARM_SERVICE)方法来获得AlarmManager对象。

以下程序中使用时间选择对话框设置闹钟的时间。

main.xml布局文件

xml version = " 1.0 " encoding = " utf-8 " ?> < LinearLayout xmlns:android = " http://schemas.android.com/apk/res/android " android:orientation = " vertical " android:layout_width = " fill_parent " android:layout_height = " fill_parent " > < Button android:id = " @+id/btn " android:text = " 设置闹钟 " android:layout_width = " fill_parent " android:layout_height = " wrap_content " /> LinearLayout >

清单文件

xml version = " 1.0 " encoding = " utf-8 " ?> < manifest xmlns:android = " http://schemas.android.com/apk/res/android " package = " com.ljq.activity " android:versionCode = " 1 " android:versionName = " 1.0 " > < application android:icon = " @drawable/icon " android:label = " @string/app_name " > < activity android:name = " .MainActivity " android:label = " @string/app_name " > < intent - filter > < action android:name = " android.intent.action.MAIN " /> < category android:name = " android.intent.category.LAUNCHER " /> intent - filter > activity > < activity android:name = " .AlarmActivity " /> < receiver android:name = " .AlarmReceiver " android:process = " :remote " /> application > < uses - sdk android:minSdkVersion = " 7 " /> manifest >

AlarmReceiver类

package com.ljq.activity; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; public class AlarmReceiver extends BroadcastReceiver{ @Override public void onReceive(Context context, Intent intent) { Intent i = new Intent(context, AlarmActivity. class ); i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(i); } }

AlarmActivity类

package com.ljq.activity; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.DialogInterface.OnClickListener; import android.os.Bundle; public class AlarmActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); // 显示对话框 new AlertDialog.Builder(AlarmActivity. this ). setTitle( " 闹钟 " ). // 设置标题 setMessage( " 时间到了！ " ). // 设置内容 setPositiveButton( " 知道了 " , new OnClickListener(){ // 设置按钮 public void onClick(DialogInterface dialog, int which) { AlarmActivity. this .finish(); // 关闭Activity } }).create().show(); } }

MainActivity类

package com.ljq.activity; import java.util.Calendar; import android.app.Activity; import android.app.AlarmManager; import android.app.Dialog; import android.app.PendingIntent; import android.app.TimePickerDialog; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.TimePicker; import android.widget.Toast; public class MainActivity extends Activity{ private Button btn = null ; private AlarmManager alarmManager = null ; Calendar cal = Calendar.getInstance(); final int DIALOG_TIME = 0 ; // 设置对话框id @Override protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.main); alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE); btn = (Button)findViewById(R.id.btn); btn.setOnClickListener( new View.OnClickListener(){ public void onClick(View view) { showDialog(DIALOG_TIME); // 显示时间选择对话框 } }); } @Override protected Dialog onCreateDialog( int id) { Dialog dialog = null ; switch (id) { case DIALOG_TIME: dialog = new TimePickerDialog( this , new TimePickerDialog.OnTimeSetListener(){ public void onTimeSet(TimePicker timePicker, int hourOfDay, int minute) { Calendar c = Calendar.getInstance(); // 获取日期对象 c.setTimeInMillis(System.currentTimeMillis()); // 设置Calendar对象 c.set(Calendar.HOUR, hourOfDay); // 设置闹钟小时数 c.set(Calendar.MINUTE, minute); // 设置闹钟的分钟数 c.set(Calendar.SECOND, 0 ); // 设置闹钟的秒数 c.set(Calendar.MILLISECOND, 0 ); // 设置闹钟的毫秒数 Intent intent = new Intent(MainActivity. this , AlarmReceiver. class ); // 创建Intent对象 PendingIntent pi = PendingIntent.getBroadcast(MainActivity. this , 0 , intent, 0 ); // 创建PendingIntent // alarmManager.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), pi); // 设置闹钟 alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), pi); // 设置闹钟，当前时间就唤醒 Toast.makeText(MainActivity. this , " 闹钟设置成功 " , Toast.LENGTH_LONG).show(); // 提示用户 } }, cal.get(Calendar.HOUR_OF_DAY), cal.get(Calendar.MINUTE), false ); break ; } return dialog; } }