public classDataTransmitUtil{

private volatile staticDataTransmitUtilinstance;

privatecallBackmCallback;

public staticDataTransmitUtilgetInstance() {

if(instance==null) {

synchronized(DataTransmitUtil.class) {

if(instance==null) {

instance=newDataTransmitUtil();

}

}

}

returninstance;

}

public voidsetText(Stringtext) {

if(mCallback!=null) {

mCallback.textChange(text);

}

}

public voidsetNull() {

if(mCallback!=null) {

mCallback=null;

}

if(instance!=null) {

instance=null;

}

}

public voidsetCallBack(callBackmCallBack) {

this.mCallback=mCallBack;

}

public interfacecallBack{

voidtextChange(Stringtext);

}

}

至于这个回调类如何使用相信聪明的你已经知道了。