1. 在BaseActivity和BaseFragment中定义ProgressDialog对象和显示、隐藏方法：

public class BaseActivity extends AppCompatActivity {

    private ProgressDialog progressDialog;

    // 显示进度条
    public void showProgressDialog(String message) {
        if (progressDialog == null) {
            progressDialog = new ProgressDialog(this);
            progressDialog.setCanceledOnTouchOutside(false);
        }
        progressDialog.setMessage(message);
        progressDialog.show();
    }

    // 隐藏进度条
    public void hideProgressDialog() {
        if (progressDialog != null) {
            progressDialog.dismiss();
        }
    }
}

public class BaseFragment extends Fragment {

    private ProgressDialog progressDialog;

    // 显示进度条
    public void showProgressDialog(String message) {
        if (progressDialog == null) {
            progressDialog = new ProgressDialog(getActivity());
            progressDialog.setCanceledOnTouchOutside(false);
        }
        progressDialog.setMessage(message);
        progressDialog.show();
    }

    // 隐藏进度条
    public void hideProgressDialog() {
        if (progressDialog != null) {
            progressDialog.dismiss();
        }
    }
}

2. 在需要显示进度条的Activity和Fragment中调用相应的方法：

public class MainActivity extends BaseActivity {

    public void someMethod() {
        // 显示进度条
        showProgressDialog("loading...");
        
        // 在这里处理耗时的操作
        
        // 隐藏进度条
        hideProgressDialog();
    }
}

public class MyFragment extends BaseFragment {

    public void someMethod() {
        // 显示进度条
        showProgressDialog("loading...");
        
        // 在这里处理耗时的操作
        
        // 隐藏进度条
        hideProgressDialog();
    }
}