ArrayList仅显示最后一个元素

Question

的ArrayList＆LT;＆GT;复制最后一个值,,,

ArrayList<CalanderQueryOutput> results = new ArrayList<CalanderQueryOutput>();

List<?> eventsToday = (List<?>) filter.filter(calendar.getComponents(Component.VEVENT));
CalanderQueryOutput caldavOutput = new CalanderQueryOutput();

for (Iterator<?> i = eventsToday.iterator(); i.hasNext();) {
 Component component = (Component) i.next();
 {
  String Created=component.getProperty(Property.CREATED).toString().trim();
  String Summary = component.getProperty(Property.SUMMARY).toString().trim();

  caldavOutput.CREATED_DATE = Created;
  caldavOutput.Summary = Summary;

 }
 results.add(caldavOutput); 
}

输出仅显示最后一个值

{"CREATED_DATE":"01-Jun-2012","Summary":"Today Swimming"},{"CREATED_DATE":"01-Jun-2012","Summary":"Today Swimming"},{"CREATED_DATE":"01-Jun-2012","Summary":"Today Swimming"}

Answer 1

你应该把它放在循环中：

CalanderQueryOutput caldavOutput = new CalanderQueryOutput();

否则，您总是修改相同的caldavOutput对象。

你始终使用相同的元素并对其进行修改，并且元素将保留您给出的最后一个值。这就是为什么你认为只输出最后一个元素。

所以你应该这样做：

for (Iterator<?> i = eventsToday.iterator(); i.hasNext();) {
   Component component = (Component) i.next();{
   String Created=component.getProperty(Property.CREATED).toString().trim();
   String Summary = component.getProperty(Property.SUMMARY).toString().trim();


   CalanderQueryOutput caldavOutput = new CalanderQueryOutput(); // Here
   caldavOutput.CREATED_DATE = Created;
   caldavOutput.Summary = Summary;

  }
  results.add(caldavOutput); 
}

Answer 2

问题是您只创建一个CalenderQueryOutput，您可以修改并读取该列表。您需要创建一个新对象。

for (Iterator<?> i = eventsToday.iterator(); i.hasNext();) {
    Component component = (Component) i.next();
    String Created=component.getProperty(Property.CREATED).toString().trim();
    String Summary = component.getProperty(Property.SUMMARY).toString().trim();

    CalanderQueryOutput caldavOutput = new CalanderQueryOutput();

    caldavOutput.CREATED_DATE = Created;
    caldavOutput.Summary = Summary;
    results.add(caldavOutput); 
}

Answer 3

将其置于循环中....

CalanderQueryOutput caldavOutput = new CalanderQueryOutput();