java 如何在 Android 中获取 Spinner 选定项目
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How to get Spinner Selected Item in Android
提问by Rohodude
I am making a currency converter with two spinners. I want to make an "if" function using the values of the spinner's selected item like below.
我正在制作一个带有两个微调器的货币转换器。我想使用如下所示的微调器所选项目的值创建一个“if”函数。
@Override
public void onClick(View v) {
if (spinner1.getSelectedItem()=="Dollars" && spinner2.getSelectedItem()=="Euros") {
convertDollarstoEuros();
}
if (spinner1.getSelectedItem()=="Euros" && spinner2.getSelectedItem()=="Euros") {
convertEurostoEuros();
}
Toast.makeText(MainActivity.this,
"OnClickListener : " +
"\nSpinner 1 : "+ String.valueOf(spinner1.getSelectedItem()) +
"\nSpinner 2 : "+ String.valueOf(spinner2.getSelectedItem()),
Toast.LENGTH_SHORT).show();
}
The problem is that the toast is showing, but the currencies aren't converting. The toast part is working, but the spinner part isn't. Any help would be greatly appreciated. Here is my LogCat:
问题是吐司正在显示，但货币没有转换。吐司部分正在工作，但微调部分没有。任何帮助将不胜感激。这是我的 LogCat：
回答by Gauthier Boaglio
Try this :
试试这个 ：
if (spinner1.getSelectedItem().toString().equals("Dollars") && spinner2.getSelectedItem().toString().equals("Euros")
...
getSelectedItem() returns an Object. info. So you have to get the corresponding string first.
Then java compares strings using equals().
getSelectedItem() 返回一个Object. 信息。所以你必须先得到对应的字符串。然后 java 使用equals().
回答by Ahmad
if (spinner1.getSelectedItem()=="Dollars" && spinner2.getSelectedItem()=="Euros") {
You can't compare Strings like that. You have to use the equals()method to compare them. Use this:
你不能这样比较字符串。您必须使用该equals()方法来比较它们。用这个：
if (spinner1.getSelectedItem().toString().equals("Dollars") && spinner2.getSelectedItem().toString().equals("Euros")) {}
回答by Vinay Ganesh
Check whether you called the id correctly or not? When I was working when improper id was called this exception used to arise. For eg In TextView, findViewById(R.id.textView1) but in xml file we may have set it to textView2.
检查您是否正确调用了 id？当我在工作时调用了不正确的 id，这个异常曾经出现过。例如，在 TextView 中，findViewById(R.id.textView1) 但在 xml 文件中，我们可能已将其设置为 textView2。
