bn3.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View source)
            {
                AlertDialog.Builder builder = new AlertDialog.Builder(EditNote.this)
                        .setTitle("Warn")
                        .setIcon(R.drawable.imgbtn1)
                        .setMessage("简单对话框");
                //设置对话框的确定选项
                builder.setPositiveButton("确定", new OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast toast = Toast.makeText(EditNote.this,
                                "单击了 确定 按钮.", Toast.LENGTH_SHORT);
                        toast.show();
                    }
                });
                //设置对话框的取消选项
                builder.setNegativeButton("取消", new OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast toast = Toast.makeText(EditNote.this,
                                "单击了 取消 按钮.", Toast.LENGTH_SHORT);
                        toast.show();
                    }
                });
                //
                builder.setCancelable(false);
                builder.show();
            }
        });