private ProgressDialog mProgressDlg = null;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //---开始显示ProgressDialog对话框

        mProgressDlg = ProgressDialog.show(this, "提示", "正在在加载", true);

        //----通过线程模拟加载任务

        new Thread(){

            public void run() {

                try {

                    Thread.sleep(5000);

                    //---加载完成后必须Progress 对话框

                    mProgressDlg.dismiss();

                }

                catch(Exception ex) {

                    ex.printStackTrace();

                }

            }

        };

    }