寄件者 scratchlab |
Jimmy's papa想試試看在XOOM上,是否能隨時按Home鍵後回到主畫面後,就有個氣壓計小工具(Widget)告訴我目前的氣壓值,這工具可以教Jimmy看著氣壓值並且對照戶外的天氣,去了解兩者之間的關係,而且順便讓Jimmy回想一下上個月到科工館玩氣壓體驗艙當時的感覺
不過Jimmy's papa寫這個小工具時,竟然發覺氣壓值無法更新,一查之下android:updatePeriodMillis這個屬性竟然Android 1.5版後就沒效了(這是網友說的,有待查證),官方文件也提到"Updates requested with updatePeriodMillis will not be delivered more than once every 30 minutes."
解決之道有AlarmManager或TimerTask兩種方式解決,Jimmy's papa覺得TimerTask比較簡單,以下是程式碼
package com.jimmyscratchlab.androidbarometerwidget;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.Timer;
import java.util.TimerTask;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.ComponentName;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.text.format.DateFormat;
import android.util.Log;
import android.widget.RemoteViews;
public class AndroidBarometerWidget extends AppWidgetProvider {
private static final String TAG = "sensor";
private SensorManager sm;
private String value = "";
@Override
public void onUpdate(Context context,AppWidgetManager appWidgetManager, int[] appWidgetIds) {
// TODO Auto-generated method stub
sm = (SensorManager)getSystemService(Context.SENSOR_SERVICE);
int sensorType = Sensor.TYPE_PRESSURE;
sm.registerListener(myPressureListener,sm.getDefaultSensor(sensorType),SensorManager.SENSOR_DELAY_NORMAL);
Timer timer = new Timer();
timer.scheduleAtFixedRate(new MyTime(context, appWidgetManager), 1, 500);
}
private class MyTime extends TimerTask
{
RemoteViews remoteViews;
AppWidgetManager appWidgetManager;
ComponentName thisWidget;
public MyTime(Context context, AppWidgetManager appWidgetManager)
{
this.appWidgetManager = appWidgetManager;
remoteViews = new RemoteViews(context.getPackageName(), R.layout.main);
thisWidget = new ComponentName(context, AndroidBarometerWidget.class);
}
@Override
public void run()
{
remoteViews.setTextViewText(R.id.now, value);
appWidgetManager.updateAppWidget(thisWidget, remoteViews);
}
}
final SensorEventListener myPressureListener = new SensorEventListener(){
public void onSensorChanged(SensorEvent sensorEvent){
if(sensorEvent.sensor.getType() == Sensor.TYPE_PRESSURE){
Log.i(TAG,"onSensorChanged");
java.text.DecimalFormat df = new java.text.DecimalFormat("#.#");
value = "目前氣壓(PRESSURE): "+ df.format( sensorEvent.values[0] )+"millibars";
}
}
public void onAccuracyChanged(Sensor sensor , int accuracy){
Log.i(TAG, "onAccuracyChanged");
}
};
}
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