[英]Making sure Integer.parseInt(String) is a valid int in java
I am attempting to get some basic info about a user, such as height, weight, ect. 我正在尝试获取有关用户的一些基本信息,例如身高,体重等。
I am using EditText objects and getText()
to retrieve the text from what the user has typed. 我正在使用EditText对象和getText()
从用户输入的内容中检索文本。 Then I convert that to a string, and finally convert everything to an int using Integer.parseint(String)
. 然后,我将其转换为字符串,最后使用Integer.parseint(String)
将所有内容转换为int。 Below is an example of what I am attempting to do if that was confusing. 下面是一个我试图做的令人困惑的示例。
if((height.getText().length() > 0) && (???)) {
mHeight = Integer.parseInt(height.getText().toString());
} else {
Toast.makeText(getBaseContext(), "Please enter your height, in inches, rounded to the nearest inch", Toast.LENGTH_SHORT).show();
canContinue = -1;
}
I used height.getText().length() > 0
to make sure that the user has at least put something into the field, but if the user puts characters, then the program crashes. 我使用height.getText().length() > 0
来确保用户至少在该字段中放置了一些内容,但是如果用户放置了字符,则该程序将崩溃。
The (???) is the assertion I am trying to complete here, that will return a false when the result isn't a valid int. (???)是我要在此处完成的断言,当结果不是有效的int时,它将返回false。 Also note that I initialized mHeight as a primitive int here int mHeight
还要注意,我在这里将mHeight初始化为基本int int mHeight
Note : height is an EditText
object and I initialized it like so: height = (EditText) findViewById(R.id.height);
注意 :height是一个EditText
对象,我将其初始化为: height = (EditText) findViewById(R.id.height);
Short of doing some complicated validations, I would simply try to parse and catch any exceptions. 除了进行一些复杂的验证之外,我只是尝试解析并捕获任何异常。
//test that the value is not empty and only contains numbers
//to deal with most common errors
if(!height.getText().isEmpty() && height.getText().matches("\\d+")) {
try {
mHeight = Integer.parseInt(height.getText());
} catch (NumberFormatException e) { //will be thrown if number is too large
//error handling
}
}
use height.getText().matches("\\\\d+")
to check if that is a number only 使用height.getText().matches("\\\\d+")
检查是否仅是数字
like: 喜欢:
if((height.getText().length() > 0) && height.getText().toString().matches("\\d+")) {
}
Write the following method and call it instead of "???" 编写以下方法,然后调用它而不是“ ???”
public static boolean isNumeric(String str)
{
try
{
int d = Integer.parseInt(str);
}
catch(NumberFormatException nfe)
{
return false;
}
return true;
}
Just try parsing it an catch any exceptions:- 只需尝试解析它即可捕获任何异常:
try {
int mHeight = 0;
if (height.getText().length() > 0) {
mHeight = Integer.parseInt(height.getText().toString());
}
} catch (NumberFormatException ex) {
Toast.makeText(getBaseContext(), "Please enter your height, in inches, rounded to the nearest inch", Toast.LENGTH_SHORT).show();
canContinue = -1;
}
If you are just trying to get numbers add inputType attribute to your EditText 如果您只是想获取数字,请在您的EditText中添加inputType属性
like 喜欢
android:inputType="numberDecimal"
then users can only enter numbers into the EditText,hence no error while parsing it. 那么用户只能在EditText中输入数字,因此解析时不会出现错误。
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