AlertDialog使用

Dialog alertDialog = new AlertDialog.Builder(LoginActivity.this);
		alertDialog.setTitle("提示");
		alertDialog.setMessage("該手機號未註冊是否去註冊？");
		alertDialog.setPositiveButton("確定",
				new DialogInterface.OnClickListener() {

					@Override
					public void onClick(DialogInterface dialog, int which) {
						// TODO Auto-generated method stub
						Intent registerIntent = new Intent(LoginActivity.this,
								RegisterActivity.class);
						registerIntent.putExtra("telphone",
								util.getText(loginPhoneNum));
						startActivity(registerIntent);
					}
				});
		alertDialog.setNegativeButton("取消", null);
		alertDialog.create();

alertDialog.show();