关于在非UI线程中进行UI操作会出现问题： Can't create handler inside thread that has not called Looper.prepare()

Activity，Service属于主线程，在主线程中才能更新UI，如toast等。其他线程中不能直接使用，否则产生 Can't create handler inside thread that has not called Looper.prepare()的错误，这时可以使用Handler来处理，Handler可以在Activity和Service中。

功能：当在非UI线程中调用CallPayment()时，弹出对话框。

public void CallPayment(String a) {
h.post(pay);
}

Handler h =
new Handler(){


public void handleMessage (Message msg)
{

switch(msg.what)
{

case HANDLER_TEST:
confirmPay()；

break;

case HANDLER_OVER:
h.removeCallbacks(pay);

break;
}
}
};

Runnable pay =new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
Message msg = new Message();
msg.what = HANDLER_TEST;
h.sendMessage(msg);
}
};
public
void confirmPay(){
Dialog
dialog=new AlertDialog.Builder(DevilsAtTheGateGameActivity.this)
.setMessage(payStr+"EP을 구매하겠습니까?\n금액:"+payStr+"원")
.setPositiveButton(R.string.confirm_pay_yes,new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog,int whichButton) {
//DoSomething
}
})
.setNegativeButton(R.string.confirm_pay_no,new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog,int whichButton) {
dialog.dismiss();
Message msg =
new Message();
msg.what =HANDLER_OVER;

h.sendMessage(msg);
}
}).show();
}
}