开源项目之Android 向下刷新列表

Android PullToRefresh为 Android 应用提供一个向下滑动即刷新列表的功能。

项目如图：

效果如图：

包含测试文件就2个目标文件！

主要类如下：

[java]
public class PullToRefreshListView extends ListView implements OnScrollListener
{

    private static final int TAP_TO_REFRESH = 1;
    private static final int PULL_TO_REFRESH = 2;
    private static final int RELEASE_TO_REFRESH = 3;
    private static final int REFRESHING = 4;

    private static final String TAG = "PullToRefreshListView";

    private OnRefreshListener mOnRefreshListener;

    /**
     * 收到通知的监听器每次滚动列表。
     */
    private OnScrollListener mOnScrollListener;
    private LayoutInflater mInflater;

    private RelativeLayout mRefreshView;
    private TextView mRefreshViewText;
    private ImageView mRefreshViewImage;
    private ProgressBar mRefreshViewProgress;
    private TextView mRefreshViewLastUpdated;

    private int mCurrentScrollState;
    private int mRefreshState;

    private RotateAnimation mFlipAnimation;
    private RotateAnimation mReverseFlipAnimation;

    private int mRefreshViewHeight;
    private int mRefreshOriginalTopPadding;
    private int mLastMotionY;

    private boolean mBounceHack;

    public PullToRefreshListView(Context context)
    {
        super(context);
        init(context);
    }

    public PullToRefreshListView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        init(context);
    }

    public PullToRefreshListView(Context context, AttributeSet attrs,
            int defStyle)
    {
        super(context, attrs, defStyle);
        init(context);
    }

    private void init(Context context)
    {
        //我们需要在代码中加载所有的动画，而不是通过XML
        mFlipAnimation = new RotateAnimation(0, -180,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f);
        mFlipAnimation.setInterpolator(new LinearInterpolator());
        mFlipAnimation.setDuration(250);
        mFlipAnimation.setFillAfter(true);
        mReverseFlipAnimation = new RotateAnimation(-180, 0,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f);
        mReverseFlipAnimation.setInterpolator(new LinearInterpolator());
        mReverseFlipAnimation.setDuration(250);
        mReverseFlipAnimation.setFillAfter(true);

        mInflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        mRefreshView = (RelativeLayout) mInflater.inflate(
                R.layout.pull_to_refresh_header, this, false);
        mRefreshViewText = (TextView) mRefreshView
                .findViewById(R.id.pull_to_refresh_text);
        mRefreshViewImage = (ImageView) mRefreshView
                .findViewById(R.id.pull_to_refresh_image);
        mRefreshViewProgress = (ProgressBar) mRefreshView
                .findViewById(R.id.pull_to_refresh_progress);
        mRefreshViewLastUpdated = (TextView) mRefreshView
                .findViewById(R.id.pull_to_refresh_updated_at);

        mRefreshViewImage.setMinimumHeight(50);
        mRefreshView.setOnClickListener(new OnClickRefreshListener());
        mRefreshOriginalTopPadding = mRefreshView.getPaddingTop();

        mRefreshState = TAP_TO_REFRESH;

        addHeaderView(mRefreshView);

        super.setOnScrollListener(this);

        measureView(mRefreshView);
        mRefreshViewHeight = mRefreshView.getMeasuredHeight();
    }

    @Override
    protected void onAttachedToWindow()
    {
        super.onAttachedToWindow();
        setSelection(1);
    }

    @Override
    public void setAdapter(ListAdapter adapter)
    {
        super.setAdapter(adapter);

        setSelection(1);
    }

    /**
     * 设置将接收通知的侦听器，每次滚动列表。
     * @param l补充：移动开发 , Android ,