所以我有一个TreeMap<Integer, Transmitter>
并通过foreach我试图修改发送器的内部属性,但感觉它是在TreeMap中制作对象的副本,因为它不会改变TreeMap中的值。
我的foreach代码:
for (TreeMap<Integer, Transmitter> current : transmitterDiagnosticMap.values()) {
for (Transmitter t : current.values()) {
String transmitterError = t.printErrorReport(date, appContext);
if (transmitterError != null)
stringsErrorsAndWarnings.add(transmitterError);
}
}
我的printErrorReport代码:
public String printErrorReport(String data, Context context) {
String output = null;
if (this.writeOnReport()) { // This is the function that will modify the object
output = data + " - " + this.getTension();
}
return output;
}
// This is the method that tells whether or not the report will be written, and changes the variable lastStatus if necessary
private boolean writeOnReport() {
if (this.status > 0) {
if (this.lastStatus == 0 || this.lastStatus != this.status) {
this.lastStatus = this.status;
return true;
}
return false;
} else {
this.lastStatus = 0;
return false;
}
}
我注意到Transmitter t
实际上将值从lastStatus = 0
更改为lastStatus = 1
,但TreeMap中没有任何更改。
答案 0 :(得分:2)
您必须使用迭代器来改变TreeMap中的值。使用current.values()
将创建副本而不是改变对象。
您需要迭代TreeMap的键并更新值。
for (TreeMap<Integer, Transmitter> current : transmitterDiagnosticMap.values()) {
for (Map.Entry<Integer, Transmitter> entry : current.entrySet()) {
Transmitter t = entry.getValue();
String transmitterError = t.printErrorReport(date, appContext);
if (transmitterError != null)
stringsErrorsAndWarnings.add(transmitterError);
entry.setValue(t);
}
}