统制android弹出框不消失

控制android弹出框不消失
Android中的弹出框在被点击时， 无论点击哪个按钮都会关闭窗口。 但是有的情况下我们不需要立即关闭窗口。下面的情况是弹出框中要求用户输入文件名， 并在点击确定时检查文件名的合法性， 不合法则提示用户重新输入， 弹出框要保持在界面上。 点击取消时弹出框消失。 这里通过对控件的反射来实现：
/**our button handler**/
    private ButtonHandler bHandler;

//pop up dialog with own button handler
    private void popUpDialog(AlertDialog dialog) {
        /*
         * alert dialog's default handler will always close dialog whenever user
         * clicks on which button. we have to replace default handler with our
         * own handler for blocking close action.
         * Reflection helps a lot.
         */
        try {
            Field field = dialog.getClass().getDeclaredField("mAlert");
            field.setAccessible(true);
           
            //retrieve mAlert value
            Object obj = field.get(dialog);
            field = obj.getClass().getDeclaredField("mHandler");
            field.setAccessible(true);
            //replace mHandler with our own handler
            field.set(obj, bHandler);
        } catch (SecurityException e) {
            Debug.error(e.getMessage());
        } catch (NoSuchFieldException e) {
            Debug.error(e.getMessage());
        } catch (IllegalArgumentException e) {
            Debug.error(e.getMessage());
        } catch (IllegalAccessException e) {
            Debug.error(e.getMessage());
        }
       
        //we can show this dialog now.
        dialog.show();
    }
    /*
     * define our own button handler, do not deal with dismiss message.
     */
    class  ButtonHandler  extends  Handler {

         private  WeakReference<DialogInterface> mDialog;

         public ButtonHandler(DialogInterface dialog) {
            mDialog = new WeakReference<DialogInterface>(dialog);
         }

         public void handleMessage(Message msg) {
             switch (msg.what) {
                 case DialogInterface.BUTTON_POSITIVE:
                 case DialogInterface.BUTTON_NEGATIVE:
                 case DialogInterface.BUTTON_NEUTRAL:
                    ((DialogInterface.OnClickListener) msg.obj).onClick(mDialog
                            .get(), msg.what);
                     break ;
            }
        }
    }

然后创建一个AlertDialog时如下去调用：
//create dialog
            mDialog = new AlertDialog.Builder(mContext)
            .setView(selectImageView)
            .setNegativeButton(android.R.string.cancel, mOnDialogClickListener)
            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int arg1) {
                    //check input file name
                    if (isValidFileName(fileNameInput.getText().toString())) {
                        String fileName = fileNameInput.getText().toString().trim();
                        mediaList.get(0).setName(fileName);
                        saveMedia(mediaList);
                        dialog.dismiss();
                    } else {
                        Toast.makeText(mContext, R.string.invalid_file_name, 1500).show();
                    }
                   
                }
            }).create();
mOnDialogClickListener用来处理关闭窗口事件：
/*
     * cancel dialog listener
     */
    OnClickListener mOnDialogClickListener = new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int buttonId) {
            switch (buttonId) {
                case DialogInterface.BUTTON_NEGATIVE:
                    dialog.dismiss();
                    break;
                case DialogInterface.BUTTON_POSITIVE:
                   
                    break;
            }
           
        }
    };