Java setText() 方法是否总是将值设置为字符串？
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Does setText() method always set value to a string?
提问by Toms
Does the method setText() always set to a string? If we want to set a Double value to the text field, hows it done?
方法 setText() 是否总是设置为字符串？如果我们想给文本字段设置一个 Double 值，怎么做？
采纳答案by MC Emperor
setText()only accepts a String. In order to insert a double, you can just concatenate the double to a string:
setText()只接受一个String. 为了插入 a double，您可以将 double 连接到一个字符串：
double someDouble = 2.5;
yourJTextField.setText("" + someDouble);
Notice that the double displays as 2.5. To format the double, see String.format().
请注意，double 显示为2.5。要格式化双精度，请参阅String.format()。
Edit, 5 years later
5年后编辑
I agree with the other answers that it is cleaner to use Double.toString(someDouble)to do the conversion.
我同意其他答案，即使用Double.toString(someDouble)它进行转换更清洁。
回答by JB Nizet
You transform the Double to a string first:
您首先将 Double 转换为字符串：
textField.setText(myDouble.toString());
At the risk of contradicting the other answers here, a primitive double should, IMHO, be transformed to a String using Double.toString(d)or String.valueOf(d), which expresses the intent more clearly (and is more efficient) than concatenation.
冒着与此处其他答案相矛盾的风险，恕我直言，原始 double 应该转换为 String 使用Double.toString(d)or String.valueOf(d)，这比串联更清晰（并且更有效）表达意图。
回答by camickr
If you have an actual Double object then you can use:
如果您有一个实际的 Double 对象，那么您可以使用：
textField.setText( doubleValue.toString() );
Or, if you have a double primitive you can use:
或者，如果您有一个双原语，您可以使用：
textField.setText( doubleValue + "" );
