自定义Dialog中设置进度条进度的问题

Question

自定义Dialong中包含了 ProgressBar 。 在调用Dialog的时候，如何控制 进度条的进度 ？public void onClick(DialogInterface dialog, int which) {
                LayoutInflater inflater = getLayoutInflater();
                View layout = inflater.inflate(R.layout.sync_dialog,
                        (ViewGroup) findViewById(R.id.dialog));
                AlertDialog.Builder sync_dialog = new Builder(HomeActivity.this);
                sync_dialog.setIcon(android.R.drawable.ic_dialog_info);
                sync_dialog.setTitle("号簿更新");
                sync_dialog.setView(layout);
                sync_dialog.setNegativeButton("取消", null);                System.out.println("progressbar set value");
                final ProgressBar sync_progressbar = (ProgressBar) findViewById(R.id.progressbar);                sync_dialog.show();                new Thread() {
                    int m_count = 0;                    public void run() {                        try {
                            while (m_count <= 100) {
                                System.out.println(m_count);
                                sync_progressbar.setProgress(m_count + 10);
                                Thread.sleep(1000);
                            }
                        } catch (InterruptedException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                    }
                }.start();
                // timer.schedule(task, 1000);            }
        });
我这样实现的时候 出现空指针错误，   sync_progressbar 为空。 求大侠们 给提示 给代码啊 

Answer 1

你是想先点击一个button再显示dialog 还是一开始就显示一个dialog？

Answer 2

设计动态的进度显示条需要将max，progress，secondaryProgress属性的值，通过循环累加 可以参考API Demos下VIEWS->ProgressBar

Answer 3

感谢楼上的回答 ， 发现问题了   
改成如下：
final ProgressBar sync_progressbar = (ProgressBar) layout.findViewById(R.id.progressbar);结贴给分