private void openDialog() {
 LinearLayout linearLayout = (LinearLayout) LayoutInflater.from(getContext()).inflate(R.layout.change_password_dialog, null);
 final EditText originPasswordEt = (EditText) linearLayout.findViewById(R.id.origin_password);
 TextView forgetPassword = (TextView) linearLayout.findViewById(R.id.forget_password);

 final AlertDialog dialog = new AlertDialog.Builder(getContext())
  .setView(linearLayout)
  .setPositiveButton("确定", new DialogInterface.OnClickListener() {
   @Override
    public void onClick(DialogInterface dialog, int which) {
    String originPassword = originPasswordEt.getText().toString().trim();
     //传到后台
    }
  })
  .create();

 dialog.show();
}

final AlertDialog dialog = new AlertDialog.Builder(getActivity())
  .setTitle(msg)
  .setView(layout)
  .setNegativeButton("取消", new DialogInterface.OnClickListener() {
   @Override
   public void onClick(DialogInterface dialog, int which) {
    dialog.dismiss();
   }
  })
  .setPositiveButton("submit",null)
  .setCancelable(true)
  .create();
dialog.show();

//为了避免点击 positive 按钮后直接关闭 dialog,把点击事件拿出来设置
dialog.getButton(AlertDialog.BUTTON_POSITIVE)
  .setOnClickListener(new View.OnClickListener() {

 @Override
 public void onClick(View v) {
  Pattern pattern = Pattern.compile("[0-9]*");
  Matcher matcher = pattern.matcher(editText.getText());
  if (!matcher.matches()){
   showToast("请输入正确的 ID");
   break;
  }
  dialog.dismiss();
  }
 }
});