Android：通过CountDownTimer更新进度条

我只是在某个触发器上显示一个倒计时片段，其中包括一个进度条，可以减少倒数计时器的滴答计数 .

我正在使用以下简单步骤：

• 在 onCreateView 片段中调用 startTimer() .

• 在 startTimer() 中定义 CountDownTimer 类，其中 onTick 方法减少 ProgressBar 的进度， onFinish 显示Toast消息 .

• 使用 getActivity().runOnUIThread() 在UI线程上启动此计时器

问题是计时器执行但是 ProgressBar 一直显示不确定的进度，即它保持不变 . 在结束时也会看到Toast，但进度条没有任何变化 .

这里出了什么问题？

以下是当前代码：

public class IncomingRequestFragment extends Fragment {

    private OnFragmentInteractionListener mListener;
    private FrameLayout root;
    private CountDownTimer mCountDownTimer;
    private ProgressBar mProgressBar;

    public IncomingRequestFragment() {
        // Required empty public constructor
    }


    public static IncomingRequestFragment newInstance(String param1, String param2) {
        IncomingRequestFragment fragment = new IncomingRequestFragment();
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }
    int progress=25;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        root = (FrameLayout) inflater.inflate(R.layout.fragment_incoming_request, container, false);
        mProgressBar = (ProgressBar) root.findViewById(R.id.countDown);
        progress = mProgressBar.getMax();
        mProgressBar.setIndeterminate(false);
        mProgressBar.setProgress(progress);
        startTimer();
        return root;
    }

    private void startTimer() {
        mCountDownTimer = new CountDownTimer(25000,1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                mProgressBar.setProgress(progress--);
                Log.d("count",String.valueOf(progress));
            }

            @Override
            public void onFinish() {
                Toast.makeText(getContext(),"You just missed a trip!",Toast.LENGTH_SHORT).show();
            }
        };
        getActivity().runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mCountDownTimer.start();
            }
        });
    }

    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }


    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }
}

Layout XML:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.taxiwaxidriver.ui.fragments.IncomingRequestFragment">

    <ProgressBar
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/countDown"
        android:layout_margin="60dp"
        android:max="25"
        android:progressTint="@android:color/holo_blue_dark"
        android:progressBackgroundTint="@android:color/holo_blue_dark"
        android:progress="25"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:padding="12dp"
        android:weightSum="2"
        android:orientation="horizontal">
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textColor="@color/white"
            android:text="REJECT"
            android:id="@+id/rideLater"
            android:background="@drawable/rounded_button_left"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="ACCEPT"
            android:textColor="@color/white"
            android:background="@drawable/rounded_button_right"
            android:id="@+id/rideNow"/>

    </LinearLayout>

</FrameLayout>

Output of above code is:

05-07 10:49:05.623 21455-21455 D/count: 24
05-07 10:49:06.626 21455-21455 D/count: 23
05-07 10:49:07.636 21455-21455 D/count: 22
05-07 10:49:08.653 21455-21455 D/count: 21
.
.
.
05-07 10:49:28.917 21455-21455 D/count: 1<br>