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我是新手在Java/ADT中，并试图从“活动A”到“活动B”获取数组。该应用程序从网页获取信息，然后将其保存在一对数组中并显示信息。我想点击一个“go to graph”按钮（调用viewallday（））重定向到活动B，活动B将显示包含所有这些信息的图形。从BackgroundTask方法获取数组到另一个活动
问题是，它们是自刷新阵列（1秒刷新），并且当应用程序处于图形模式（活动B）时，不希望失去此功能。任何想法如何做到这一点？
提前感谢大家，我从这个网站学到了很多东西。
UPDATE：我试图用Singleton模式做到这一点。但LogCat说：
02-26 22：21：59.300：E/AndroidRuntime（2677）：致命例外：主 02-26 22：21：59.300：E/AndroidRuntime（2677）：java.lang.RuntimeException ：无法启动活动ComponentInfo {com.example.Chispa/com.example.Chispa.Activity_allday}：android.os.NetworkOnMainThreadException 02-26 22：21：59.300：E/AndroidRuntime（2677）：引起：android.os .NetworkOnMainThreadException
UPDATE 2：终于明白了！下面是我使用的代码：
下面是活动A代码：
public class MainActivity extends Activity {
private TextView tvmax, tvmid, tvmin, tvactualval,tvvaloractual,tvdate;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvdate=(TextView)findViewById(R.id.tvdate);
tvvaloractual=(TextView)findViewById(R.id.tvvaloractual);
tvmax=(TextView)findViewById(R.id.tvmaximo);
tvmid=(TextView)findViewById(R.id.tvmedio);
tvmin=(TextView)findViewById(R.id.tvminimo);
new BackGroundTask().execute();
callAsynchronousTask();
}
public void callAsynchronousTask() {
final Handler handler = new Handler();
Timer timer = new Timer();
TimerTask doAsynchronousTask = new TimerTask() {
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
try {
BackGroundTask performBackgroundTask = new BackGroundTask();
// PerformBackgroundTask this class is the class that extends AsynchTask
performBackgroundTask.execute();
} catch (Exception e) {
// TODO Auto-generated catch block
}
}
});
}
};
timer.schedule(doAsynchronousTask, 0, 1000); //execute in every 1000 ms
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public class Pair
{
public String[] bar;
public String[] values;
}
public void viewallday(View view) {
Intent intent = new Intent(MainActivity.this, Activity_allday.class);
startActivity(intent);
}
class BackGroundTask extends AsyncTask<Void, Void, Pair> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
public String[] getValuesGraph(Document doc) {
int cont=24,var=7;
String bar[] = new String[cont];
/*
* Getting elements from the graphic in an array from 0-23. 0 it's 1:00am, 23 it's 00:00am
*/
for (cont=0; cont < 24; cont++){
String onMouseOver = doc.select("a").get(var+cont).attr("onMouseOver");
bar[cont] = onMouseOver.split("'")[9];
}
return bar;
}
public String[] getValuesFooter(Document doc) {
String values[] = new String[7];
/*
* Getting elements from the graphic footer
*/
String delimiters= "[ /]+";
Elements elements = doc.select("td.cabeceraRutaTexto");
elements.size(); // 6
/* Getting text from table */
values[0] = elements.get(0).text(); // TITLE
values[1] = elements.get(1).text(); // TEXT MAX VALUE
values[2] = elements.get(2).text(); // TEXT MIDDLE VALUE
values[3] = elements.get(3).text(); // TEXTO MIN VALUE
/* Getting numbers from table */
values[4] = elements.get(4).text().split(delimiters)[0]; // NUMBER MAX VALUE
values[5] = elements.get(5).text().split(delimiters)[0]; // NUMBER MIDDLE VALUE
values[6] = elements.get(6).text().split(delimiters)[0]; // NUMBER MIN VALUE
return values;
}
public Document getUrl(){
try {
URL url= new URL("http://www.endesaonline.com/canal/precios/Canal_Preciosdelpool.asp?FECHA=20140226");
/*URL url= new URL("http://www.endesaonline.com/canal/precios/Canal_Preciosdelpool.asp?lang=es&frameId=4064&segmento=1&promocion=");*/
Document doc = Jsoup.connect(url.toString()).get();
return doc;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
public Pair doInBackground(Void... params) {
Pair p = new Pair();
GlobalVariables gs = (GlobalVariables) getApplication();
gs.setBar(getValuesGraph(getUrl()));
p.bar = getValuesGraph(getUrl());
p.values = getValuesFooter(getUrl());
return p;
}
public String ActualHourValue() {
Format formatter = new SimpleDateFormat("H");
String onlyhour = formatter.format(new Date());
return onlyhour;
}
public void ShowDateHour(){
Calendar c = Calendar.getInstance();
SimpleDateFormat df3 = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss a");
String formattedDate3 = df3.format(c.getTime());
tvdate.setText("Fecha y hora actuales : "+formattedDate3);
}
@Override
protected void onPostExecute(Pair p) {
int hour = Integer.parseInt(ActualHourValue());
tvvaloractual.setText(p.bar[hour]+" €/MWh");
tvmax.setText(p.values[4]+" €/MWh");
tvmid.setText(p.values[5]+" €/MWh");
tvmin.setText(p.values[6]+" €/MWh");
ShowDateHour();
/*super.onPostExecute(p.values);*/
}
}
}
这里是为活动B代码：
public class Activity_allday extends MainActivity {
private TextView tvall;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.all_day_price);
TextView tvall=(TextView)findViewById(R.id.tvall);
GlobalVariables gs = (GlobalVariables) getApplication();
String[] s = gs.getBar();
tvall.setText(s[0]);
}
}
这里是一个全局变量类谁捕获我想发送到活动B的阵列：
public class Activity_allday extends MainActivity {
private TextView tvall;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.all_day_price);
TextView tvall=(TextView)findViewById(R.id.tvall);
GlobalVariables gs = (GlobalVariables) getApplication();
String[] s = gs.getBar();
tvall.setText(s[0]);
}
}
就这样！希望这将有助于未来的用户。
谢谢大家的帮助。
您是否尝试过将数据保存到某个共享位置（例如应用程序单例）？ – Stephan
不，我会在Google上看看关于单身人士和他的申请的问题。 非常感谢你@Stephan – user3321425
你也可以使用parcel。有关更多信息，请参阅[包裹]（https://developer.android.com/reference/android/os/Parcel.html）。 – saiarcot895