我想检查字符是否为空,但为什么这段代码不起作用?
letterChar == null
也不起作用。我在谷歌上搜索了很多问题,但没有看到任何解决方案,大多数解决方案都是关于String
的。String letter = enterletter.getText().toString();
char letterChar = letter.charAt(0);
if(letterChar == ' ' || letterChar == NULL) // this is where the code won't works
{
Toast.makeText(getApplicationContext(), "Please enter a letter!", Toast.LENGTH_LONG).show();
}
String letter = enterletter.getText().toString().trim(); // 这将删除空格 if (letter.length() < 1) { Toast.makeText(getApplicationContext(), "请输入一个字母!", Toast.LENGTH_LONG).show(); }
- Meet Patel