Java 你可以在 Android 的 switch-case 中使用条件语句吗？
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Can you use conditional statements in switch-case in Android?
提问by Robert
I can't seem to find a straight forward yes or no to this in my searching. In Android, is there a way to use a conditional statement in case-switch? For example, with age being an int value:
在我的搜索中，我似乎无法直接确定是或否。在 Android 中，有没有办法在 case-switch 中使用条件语句？例如，age 是一个 int 值：
switch (age){
case (>79):
// Do this stuff
break;
case (>50):
// Do this other stuff
break;
etc, etc
I've tried several ways to code this (completely shooting in the dark) and come up with compiler errors, and I've also tried a nested IF statement, but it doesn't support break so the logic breaks down and it ends up also executing ELSE code lower in the nesting. I feel like switch-case is my best bet but I can't find an example of the correct syntax for what I'm trying to do! Any help would be appreciated. All the examples I find just use switch-case for a few things like if it is a 1 do this, if it's a 2 do that, but without making 100 case statements to check against age, I'm not sure how else to work this.
我尝试了几种方法来对此进行编码（完全在黑暗中拍摄）并提出编译器错误，并且我还尝试了嵌套的 IF 语句，但它不支持 break 所以逻辑崩溃了还在嵌套中执行较低的 ELSE 代码。我觉得 switch-case 是我最好的选择，但我找不到我想要做的正确语法的例子！任何帮助，将不胜感激。我发现的所有示例都只是将 switch-case 用于一些事情，例如如果是 1 则执行此操作，如果是 2 则执行此操作，但是没有进行 100 个 case 语句来检查年龄，我不知道如何工作这个。
采纳答案by Elliott Frisch
No. You cannot do this,
不，你不能这样做，
switch (age){
case (>79):
// Do this stuff
break;
case (>50):
// Do this other stuff
break;
}
You need an ifand else,
你需要一个ifand else,
if (age > 79) {
// do this stuff.
} else if (age > 50) {
// do this other stuff.
} // ...
回答by brso05
You can't do this use if then statement.
您不能使用 if then 语句执行此操作。
if(age > 79)
{
//do stuff
}
else if(age > 50)
{
//do stuff
}
else
{
/do stuff
}
etc...
等等...
回答by shinjw
If you are using a loop you might want to look at What is the "continue" keyword and how does it work in Java?. This is not a good place to use switch.
如果您正在使用循环，您可能需要查看什么是“continue”关键字以及它在 Java 中是如何工作的？. 这不是使用 switch 的好地方。
if(age > 79)
{
//do stuff
continue; // STOP FLOW HERE AND CONTINUE THE LOOP
}
else if(age > 50)
{
//do stuff
continue; // STOP FLOW HERE AND CONTINUE THE LOOP
}
回答by NavinRaj Pandey
each case of switch is supposed to be an integer or String since JavaSE 7 and you are trying to feed a boolean value to it so its not possible .Read oracle doc to know about java switch in detail http://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html
自 JavaSE 7 以来，开关的每种情况都应该是一个整数或字符串，并且您正试图为其提供一个布尔值，因此不可能。阅读 oracle 文档以详细了解 java 开关 http://docs.oracle.com /javase/tutorial/java/nutsandbolts/switch.html
回答by NicePixel
You can't use conditional statements with switch.
您不能将条件语句与switch.
But you CAN do it with ifstatements! If you have a loop you can use continueto stop any upcoming lines and start from the beginning of the innermost loop.
但是你可以用if语句来做到这一点！如果你有一个循环，你可以continue用来停止任何即将到来的行并从最里面的循环的开头开始。
if(age>76){
// Code...
continue;
}else if(age>50){
// More Code...
continue;
}else{
// Even more code...
continue;
}
回答by Williem
It is not possible. Instead, Try this minimalist approach
这不可能。相反，尝试这种极简主义的方法
age > 79 ? first_case_method()
: age > 50 ? second_case_method()
: age > 40 ? third_case_method()
: age > 30 ? fourth_case_method()
: age > 20 ? fifth_case_method()
: ...
: default_case_method();
回答by Vikram
It can be done. The code needs to be slightly altered.
可以办到。代码需要稍微改动一下。
public static void main(String[]arguments)
{
int x=1, age=55;
switch(x)
{
case 1: if((age>=60)&&(age<200))
System.out.println("Senior Citizen");
case 2: if((age>=18)&&(age<60))
System.out.println("Adult");
case 3: if((age>=12)&&(age<18))
System.out.println("Teenager");
break;
default :
System.out.println("Child");
break;
}
}
