更新今日天气数据
小组成员: 孙晴 宁旭冉 于昌和 黄志达 最终完成日期：15年00月00日
一、简介
本实验完成天气预报项目中更新今日天气数据的模块。
二、基础知识
bean包：
作用：封装数据 实现： get、set、toString方法
toString方法：
toString()源自Object类，重写并不是必须的，需要根据当前程序的 实际情况而定。在许多场合中,需要打印和比较出对象的内容,所以重写。 toString() 譬如一个JavaBean插入数据库时需要打印一段该JavaBean内容的日志 ，这时在JavaBean里重写toString()就显得很优美了。
解析xml数据（PULL）：
START_DOCUMENT：读取到XML的声明; END_DOCUMENT：读取到XML的结束返回； START_TAG : 读取到XML的开始标签； END_TAG：读渠道XML的结束标签； 参照XML数据解析。更新UI：
xxx.setText(): 如果xxx是Text控件，那就是设置Text的控件中的文本内容 xxx.setImageResource()： 设置ImageView中的图片，setImageResource的参数是resId，必须是drawable目录下的资源。主线程与子线程间的消息传递：
handler是线程通讯工具类。用于传递消息。它有两个队列： 1.消息队列 2.线程队列 消息队列使用sendMessage和HandleMessage的组合来发送和处理消息。 handler是Message的主要处理者，负责Message的发送，Message内 容的执行处理。后台线程就是通过传进来的Handler对象引用来sendMessage(Message)。 而使用Handler，需要implement 该类的 handleMessage(Message) 方法，它是处理这些Message的操作内容，例如Update UI。 通常需要子类化Handler来实现handleMessage方法。
三、主要思路及步骤
3.1 主要思路
完成更新今日天气的功能：已经通过消息机制,将解析的天气对象,通过消息发送给主线程,主线程接收到 消息数据后,调用 updateTodayWeather 函数,更新 UI 界面上的数据。
3.2 实践步骤
1.建立新的package，建立新的bean包--todayweather类
todayweather类有如下属性：
private String city;
private String updatetime;
private String wendu;
private String fengli;
private String shidu;
private String fengxiang;
private String pm25;
private String quality;
private String date;
private String high;
private String low;
private String type;
为每个属性写get set方法
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getUpdatetime() {
return updatetime;
}
public void setUpdatetime(String updatetime) {
this.updatetime = updatetime;
}
public String getWendu() {
return wendu;
}
public void setWendu(String wendu) {
this.wendu = wendu;
}
public String getFengli() {
return fengli;
}
public void setFengli(String fengli) {
this.fengli = fengli;
}
public String getShidu() {
return shidu;
}
public void setShidu(String shidu) {
this.shidu = shidu;
}
public String getFengxiang() {
return fengxiang;
}
public void setFengxiang(String fengxiang) {
this.fengxiang = fengxiang;
}
public String getPm25() {
return pm25;
}
public void setPm25(String pm25) {
this.pm25 = pm25;
}
public String getQuality() {
return quality;
}
public void setQuality(String quality) {
this.quality = quality;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getHigh() {
return high;
}
public void setHigh(String high) {
this.high = high;
}
public String getLow() {
return low;
}
public void setLow(String low) {
this.low = low;
}
写toString方法
public String toString() {
return "TodayWeather{" +
"city='" + city + '\'' +
", updatetime='" + updatetime + '\'' +
", wendu='" + wendu + '\'' +
", fengli='" + fengli + '\'' +
", shidu='" + shidu + '\'' +
", fengxiang='" + fengxiang + '\'' +
", pm25='" + pm25 + '\'' +
", quality='" + quality + '\'' +
", date='" + date + '\'' +
", high='" + high + '\'' +
", low='" + low + '\'' +
", type='" + type + '\'' +
'}';
}
2.将解析的数据存入TodayWeather对象中。
在MainAcitivity中写parseXML方法
private TodayWeather parseXML(String xmldata) {
TodayWeather todayWeather = null;
try{
int fengxiangCount = 0;
int fengliCount = 0;
int dateCount = 0;
int highCount = 0;
int lowCount = 0;
int typeCount = 0;
XmlPullParserFactory fac = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = fac.newPullParser();
xmlPullParser.setInput(new StringReader(xmldata));
int eventType =xmlPullParser.getEventType();
Log.d("myapp", "parseXML");
while(eventType != XmlPullParser.END_DOCUMENT){
switch(eventType) {
// 判断当前事件是否为文档开始事件
case XmlPullParser.START_DOCUMENT:
break;
// 判断是否为标签元素开始事件
case XmlPullParser.START_TAG:
if(xmlPullParser.getName().equals("resp")){
todayWeather = new TodayWeather();
todayWeather.setQuality("null");
}
if (todayWeather != null){
if(xmlPullParser.getName().equals("city")){
eventType = xmlPullParser.next();
todayWeather.setCity(xmlPullParser.getText());
Log.d("myapp", "city" + xmlPullParser.getText());
}else if(xmlPullParser.getName().equals("updatetime")){
eventType = xmlPullParser.next();
todayWeather.setUpdatetime(xmlPullParser.getText());
Log.d("myapp", "updatetime" + xmlPullParser.getText());
}else if(xmlPullParser.getName().equals("shidu")){
eventType = xmlPullParser.next();
todayWeather.setShidu(xmlPullParser.getText());
Log.d("myapp", "shidu" + xmlPullParser.getText());
}else if(xmlPullParser.getName().equals("wendu")){
eventType = xmlPullParser.next();
todayWeather.setWendu(xmlPullParser.getText());
Log.d("myapp", "wendu" + xmlPullParser.getText());
}else if(xmlPullParser.getName().equals("pm25")){
eventType = xmlPullParser.next();
todayWeather.setPm25(xmlPullParser.getText());
Log.d("myapp", "pm2.5" + xmlPullParser.getText());
}else if(xmlPullParser.getName().equals("quality")){//顺义的时候根本没执行这里啊
eventType = xmlPullParser.next();
todayWeather.setQuality(xmlPullParser.getText());
Log.d("myapp", "quality" + xmlPullParser.getText());
}
else if(xmlPullParser.getName().equals("fengxiang") && fengxiangCount == 0){
eventType = xmlPullParser.next();
todayWeather.setFengxiang(xmlPullParser.getText());
Log.d("myapp", "fengxiang" + xmlPullParser.getText());
fengxiangCount++;
}else if(xmlPullParser.getName().equals("fengli") && fengliCount == 0){
eventType = xmlPullParser.next();
todayWeather.setFengli(xmlPullParser.getText());
Log.d("myapp", "fengli" + xmlPullParser.getText());
fengliCount++;
}else if(xmlPullParser.getName().equals("date") && dateCount == 0){
eventType = xmlPullParser.next();
todayWeather.setDate(xmlPullParser.getText());
Log.d("myapp", "date" + xmlPullParser.getText());
dateCount++;
}else if(xmlPullParser.getName().equals("high") && highCount == 0){
eventType = xmlPullParser.next();
todayWeather.setHigh(xmlPullParser.getText().substring(2).trim());
Log.d("myapp", "high" + xmlPullParser.getText().substring(2).trim());
highCount++;
}else if(xmlPullParser.getName().equals("low") && lowCount == 0){
eventType = xmlPullParser.next();
todayWeather.setLow(xmlPullParser.getText().substring(2).trim());
Log.d("myapp", "low" + xmlPullParser.getText());
lowCount++;
}else if(xmlPullParser.getName().equals("type") && typeCount == 0){
eventType = xmlPullParser.next();
todayWeather.setType(xmlPullParser.getText());
Log.d("myapp", "type" + xmlPullParser.getText());
typeCount++;
}
}
break;
// 判断是否为标签元素结尾事件
case XmlPullParser.END_TAG:
break;
}
// 进入下一个元素并触发相应事件
eventType = xmlPullParser.next();
}
} catch (Exception e) {
e.printStackTrace();
}
return todayWeather;
}
利用刚写的方法，接收解析结果,并通过 Log打印是否接收正确queryWeatherCode方法里写如下代码
TodayWeather todayWeather = parseXML(responseStr);//调用parseXML
if (todayWeather != null) {
Log.d("myapp", todayWeather.toString());
3.将数据在 UI 上进行更新。
定义控件对象
private TextView cityTv, timeTv, humidityTv,weekTv,pmDataTv, pmQualityTv, tempertureTv, climateTv, windTv;
private ImageView weatherImg, pmImg;
初始化控件
void initView(){
t= (TextView) findViewById(R.id.title_city_name);
cityTv = (TextView) findViewById(R.id.city);
timeTv = (TextView) findViewById(R.id.time);
humidityTv = (TextView) findViewById(R.id.humidity);
weekTv = (TextView) findViewById(R.id.week_today);
pmDataTv = (TextView) findViewById(R.id.pm_data);
pmQualityTv = (TextView) findViewById(R.id.pm2_5_quality);
pmImg = (ImageView) findViewById(R.id.pm2_5_img);
tempertureTv = (TextView) findViewById(R.id.temperature);
climateTv = (TextView) findViewById(R.id.climate);
windTv = (TextView) findViewById(R.id.wind);
weatherImg = (ImageView) findViewById(R.id.weather_img);
cityTv.setText("N/A");
timeTv.setText("N/A");
humidityTv.setText("N/A");
weekTv.setText("N/A");
pmDataTv.setText("N/A");
pmQualityTv.setText("N/A");
tempertureTv.setText("N/A");
climateTv.setText("N/A");
windTv.setText("N/A");
}
initView()当然是在Activity创建的时候就调用了
编写 updateTodayWeather 函数，为我们的控件填写内容
// 更新天气
void updateTodayWeather (TodayWeather todayWeather){
//Log.d("myapp3", todayWeather.toString());
t.setText(todayWeather.getCity()+"天气");
cityTv.setText(todayWeather.getCity());
timeTv.setText(todayWeather.getUpdatetime() + "发布");
humidityTv.setText("湿度:" + todayWeather.getShidu());
weekTv.setText(todayWeather.getDate());
pmDataTv.setText(todayWeather.getPm25());
pmQualityTv.setText(todayWeather.getQuality());
pmImg.setImageResource(getpmImage(todayWeather.getQuality()));
tempertureTv.setText(todayWeather.getLow() + "~" + todayWeather.getHigh());
climateTv.setText(todayWeather.getType());
windTv.setText("风力:" + todayWeather.getFengli());
weatherImg.setImageResource(getImage(todayWeather.getType()));
Toast.makeText(MainActivity.this, "更新成功！", Toast.LENGTH_LONG).show();
//Log.d("到底更新几次!!!!!!!!!!!!", todayWeather.toString());
}
其中，要是先根据天气状况更新不同的图片，效果图如下：
写一个根据获得天气情况，更新对应图标的函数
private int getImage(String type) {
int imagetype=0;
switch(type) {
case "阴" : imagetype=R.drawable.biz_plugin_weather_yin;
break;
case "暴雪" : imagetype=R.drawable.biz_plugin_weather_baoxue;
break;
case "晴" : imagetype=R.drawable.biz_plugin_weather_qing;
break;
case "暴雨" : imagetype=R.drawable.biz_plugin_weather_baoyu;
break;
case "大暴雨" : imagetype=R.drawable.biz_plugin_weather_dabaoyu;
break;
case "大雪" : imagetype=R.drawable.biz_plugin_weather_daxue;
break;
case "大雨" : imagetype=R.drawable.biz_plugin_weather_dayu;
break;
case "多云" : imagetype=R.drawable.biz_plugin_weather_duoyun;
break;
case "雷阵雨冰雹" : imagetype=R.drawable.biz_plugin_weather_leizhenyubingbao;
break;
case "雷阵雨" : imagetype=R.drawable.biz_plugin_weather_leizhenyu;
break;
default:
imagetype=R.drawable.biz_plugin_weather_qing;
}
return imagetype;
}
同样对于空气质量图标的显示的函数
private int getpmImage(String pm) {
System.out.println(pm);
int pmtype=0;
switch(pm) {
case "重度污染" : pmtype=R.drawable.biz_plugin_weather_201_300;
break;
case "中度污染" : pmtype=R.drawable.biz_plugin_weather_151_200;
break;
case "轻度污染" : pmtype=R.drawable.biz_plugin_weather_101_150;
break;
case "?还有什么等级" : pmtype=R.drawable.biz_plugin_weather_51_100;
break;
case "良" : pmtype=R.drawable.biz_plugin_weather_0_50;
break;
default:
pmtype=R.drawable.biz_plugin_weather_0_50;
System.out.println("pmnull 打印的default");
break;
}
return pmtype;
}
4.定义主线程的 Handler。
private static final int UPDATE_TODAY_WEATHER = 1;
// 定义主线程的 handler
private Handler mHandler = new Handler() {
@Override
public void handleMessage(android.os.Message msg) {
switch(msg.what){
case UPDATE_TODAY_WEATHER:
updateTodayWeather((TodayWeather) msg.obj);
break;
default:
break;
}
}
};
5.在子线程中发送更新 UI 的消息。
if (todayWeather != null) {
Log.d("myapp", todayWeather.toString());
// 发送消息，由主线程更新UI
Message msg =new Message();
msg.what = UPDATE_TODAY_WEATHER;
msg.obj = todayWeather;
mHandler.sendMessage(msg);
}
四、常见问题及注意事项
1. 在处理数据时注意值为空的情况；