diff --git a/代码注释_刘翱翔/AlarmAlertActivity.java b/代码注释_刘翱翔/AlarmAlertActivity.java new file mode 100644 index 0000000..b0d38e8 --- /dev/null +++ b/代码注释_刘翱翔/AlarmAlertActivity.java @@ -0,0 +1,61 @@ +### AlarmInitReceiver.java + +```java +package net.micode.notes.ui; + +import android.app.AlarmManager; +import android.app.PendingIntent; +import android.content.BroadcastReceiver; +import android.content.ContentUris; +import android.content.Context; +import android.content.Intent; +import android.database.Cursor; + +import net.micode.notes.data.Notes; +import net.micode.notes.data.Notes.NoteColumns; + + +public class AlarmInitReceiver extends BroadcastReceiver { + + private static final String [] PROJECTION = new String [] { + NoteColumns.ID, + NoteColumns.ALERTED_DATE + }; + //对数据库的操作,调用标签ID和闹钟时间 + private static final int COLUMN_ID = 0; + private static final int COLUMN_ALERTED_DATE = 1; + + @Override + public void onReceive(Context context, Intent intent) { + long currentDate = System.currentTimeMillis(); + //System.currentTimeMillis()产生一个当前的时间,以毫秒为单位 + //这个毫秒其实就是自1970年1月1日0时起的毫秒数 + Cursor c = context.getContentResolver().query(Notes.CONTENT_NOTE_URI, + PROJECTION, + NoteColumns.ALERTED_DATE + ">? AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE, + new String[] { String.valueOf(currentDate) }, + //将long变量currentDate转化为字符串 + null); + //Cursor在这里的作用是通过查找数据库中的标签内容,找到和当前系统时间相等的标签 + + if (c != null) { + if (c.moveToFirst()) { + do { + long alertDate = c.getLong(COLUMN_ALERTED_DATE); + Intent sender = new Intent(context, AlarmReceiver.class); + sender.setData(ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, c.getLong(COLUMN_ID))); + PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, sender, 0); + AlarmManager alermManager = (AlarmManager) context + .getSystemService(Context.ALARM_SERVICE); + alermManager.set(AlarmManager.RTC_WAKEUP, alertDate, pendingIntent); + } while (c.moveToNext()); + } + c.close(); + } + //闹钟机制的启动,通常需要几个步骤 + //新建Intent、PendingIntent以及AlarmManager等 + //这里就是根据数据库里的闹钟时间创建一个闹钟机制 + } +} +``` +