使用Eclipse的Android项目给出错误：源级别低于1.7时无法打开String类型的值

Question

I was working on an android project using eclipse and suddenly i started to get this error:

Cannot switch on a value of type String for source level below 1.7. Only convertible int values or enum variables are permitted.

I tried every solution in previous similar issues but none of them worked for me...

I have Tried fixing the project and setting the JDK compliance level to 1.7 in both my project and for all project.

I am using ADT Build: v22.2.1-833290 and Eclipse:

String text = mService.getString();
switch (text) {
    case Protocols.REQUEST_SEND_MESSAGE:
        publishProgress("sent");
        break;
    case Protocols.RESPONSE_OK:
        mService.sendMessage("mesasage");   
        publishProgress("sent");  
        break;              
    default:
        break;
}

What's going on?

Answer 1

You are trying to use switch / case with String objects, which is only available in Java 1.7 or higher. Android ADT requires Java 1.6. This means you cannot use switch with String construct. Just replace it with if / else .

Replace your code with this.

String text=mService.getString();
if (Protocols.REQUEST_SEND_MESSAGE.equals(text)) {
    publishProgress("sent");
} else if (Protocols.RESPONSE_OK.equals(text)) {
    mService.sendMessage("mesasage");
    publishProgress("sent"); 
}

Another option would be to create an enum and put all Protocol constants into there. Then you will be able to use switch / case with enum values.

Answer 2

As the answer below gives more details, switch statement on String objects is a new feature introduced in Java 1.7. Unfortunatelly Android requires version 1.6 or 1.5. :

https://stackoverflow.com/a/14367642/1572408