java - 在函数中间调用Thread

Question

我正在调用一个线程，该线程将 GCM ID 返回到名为 gcmRegID 的公共(public)变量中

问题是线程只有在函数结束后才会被调用

我想知道是否有办法可以获取函数中间的 gcmRegID 的值

我将通过代码解释更多

我想获取CheckGCMID中gcmRegID的值，但我得到的是“”

String gcmRegID = "";
public void onClick(View view) {
    String CheckGCMID;
    GetGCM();
    CheckGCMID = gcmRegID; // <-- This is always return empty string
}

private void GetGCM() {
    Thread thread = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                GCMHelper gcmRegistrationHelper = new GCMHelper(
                        getApplicationContext());
                gcmRegID = gcmRegistrationHelper.GCMRegister("123456");
                // gcmRegID value is "KHDKJDIUHDHDKDK"
            } catch (Exception bug) {
                bug.printStackTrace();
            }
        }
    });

    thread.start();
}

Answer 1

您应该使用回调来异步获取您的值。

尝试这样的事情:

public void onClick(View view) {

            String CheckGCMID;
            GetGCM(new MyCallback(){
                @Override
                public void receivedString(String myString) {
                    //use your id here
                    System.out.println(myString);
                }
            });

  }


private interface MyCallback{
    public void receivedString(String myString);
}

private void GetGCM(MyCallback callback) {
    Thread thread = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                GCMHelper  gcmRegistrationHelper = new GCMHelper (getApplicationContext());
                String gcmRegID = gcmRegistrationHelper.GCMRegister("123456");
                callback.receivedString(gcmRegID);
            } catch (Exception bug) {
                bug.printStackTrace();
            }

        }
    });
    thread.start();
}