Question

我定制了一个pull-to-refresh列表视图，我重写了方法＆＃34; onTouchEvent（MotionEvent ev）＆＃34;。但是当我在屏幕上拉下来时，MotionEvent.ACTION_DOWN赢了＆＃ 39; t表演。这是我的代码。

  public class ExListView extends ListView implements AbsListView.OnScrollListener {

private int firstVisibleItemPosition; 
private int downY; // delta Y when pulling down

private final int DOWN_PULL_REFRESH = 0; 

private final int RELEASE_REFRESH = 1; 
private final int REFRESHING = 2; 
private int currentState = DOWN_PULL_REFRESH; 
private OnRefreshListener mOnRefreshListener;

private Animation upAnimation;

private Animation downAnimation; 
private View headerView; 

private ImageView ivArrow;
private ProgressBar mProgressBar; 
private TextView tvState; //  state of header
private int headerViewHeight; // header height

private View footerView; // footer
private int footerViewHeight; // footer height

private boolean isScrollToBottom; 
private boolean isLoadingMore = false; 

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

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

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

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
    if (scrollState == SCROLL_STATE_IDLE || scrollState == SCROLL_STATE_FLING) {

        if (isScrollToBottom && !isLoadingMore) {
            isLoadingMore = true;

            footerView.setPadding(0, 0, 0, 0);
            this.setSelection(this.getCount());

            if (mOnRefreshListener != null) {
                mOnRefreshListener.onLoadMore();
            }
        }
    }
}

@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
    firstVisibleItemPosition = firstVisibleItem;

    if (getLastVisiblePosition() == (totalItemCount - 1)) {
        isScrollToBottom = true;
    } else {
        isScrollToBottom = false;
    }
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            downY = (int) ev.getY();
            break;
        case MotionEvent.ACTION_MOVE:
            int moveY = (int) ev.getY();
            int diff = (moveY - downY) / 2;
            int paddingTop = -headerViewHeight + diff;
           super.onTouchEvent(ev);
            if (firstVisibleItemPosition == 0 && -headerViewHeight < paddingTop) {
                if (paddingTop > 0 && currentState == DOWN_PULL_REFRESH) {
                    currentState = RELEASE_REFRESH;
                    refreshHeaderView();
                } else if (paddingTop < 0 && currentState == RELEASE_REFRESH) {
                    currentState = DOWN_PULL_REFRESH;
                    refreshHeaderView();
                }

                headerView.setPadding(0, paddingTop, 0, 0);
                return true;
            }
            break;
        case MotionEvent.ACTION_UP:
            if (currentState == RELEASE_REFRESH) {
                headerView.setPadding(0, 0, 0, 0);
                currentState = REFRESHING;
                refreshHeaderView();

                if (mOnRefreshListener != null) {
                    mOnRefreshListener.onRefresh(); 
                }
            } else if (currentState == DOWN_PULL_REFRESH) {
                // hide header
                headerView.setPadding(0, -headerViewHeight, 0, 0);
            }
            break;
        default:
            break;
    }
    return super.onTouchEvent(ev);
}

private void init() {
    this.setOnScrollListener(this);

    //animation
    upAnimation = new RotateAnimation(0f, -180f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
    upAnimation.setDuration(500);
    upAnimation.setFillAfter(true); 

    downAnimation = new RotateAnimation(-180f, -360f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
    downAnimation.setDuration(500);
    downAnimation.setFillAfter(true); 

    //header
    headerView = View.inflate(getContext(), R.layout.listview_header, null);
    ivArrow = (ImageView) headerView.findViewById(R.id.iv_listview_header_arrow);
    mProgressBar = (ProgressBar) headerView.findViewById(R.id.pb_listview_header);
    tvState = (TextView) headerView.findViewById(R.id.tv_listview_header_state);

    headerView.measure(0, 0); 
    headerViewHeight = headerView.getMeasuredHeight();
    headerView.setPadding(0, -headerViewHeight, 0, 0);
    this.addHeaderView(headerView); 

    //footer
    footerView = View.inflate(getContext(), R.layout.listview_footer, null);
    footerView.measure(0, 0);
    footerViewHeight = footerView.getMeasuredHeight();
    footerView.setPadding(0, -footerViewHeight, 0, 0);
    this.addFooterView(footerView);
}


private void refreshHeaderView() {
    switch (currentState) {
        case DOWN_PULL_REFRESH: // pull down
            tvState.setText("Pull to refresh");
            ivArrow.startAnimation(downAnimation); 
            break;
        case RELEASE_REFRESH: // release
            tvState.setText("Release to refresh");
            ivArrow.startAnimation(upAnimation); 
            break;
        case REFRESHING: // freshing
            ivArrow.clearAnimation();
            ivArrow.setVisibility(View.GONE);
            mProgressBar.setVisibility(View.VISIBLE);
            tvState.setText("Refreshing...");
            break;
        default:
            break;
    }
}

public void hideHeaderView() {
    postDelayed(new Runnable() {
        @Override
        public void run() {
            headerView.setPadding(0, -headerViewHeight, 0, 0);
            ivArrow.setVisibility(View.VISIBLE);
            mProgressBar.setVisibility(View.GONE);
            tvState.setText("Pull to refresh");
            currentState = DOWN_PULL_REFRESH;
        }
    }, 1000);

}

public void hideFooterView() {
    postDelayed(new Runnable() {
        @Override
        public void run() {
            footerView.setPadding(0, -footerViewHeight, 0, 0);
            isLoadingMore = false;
        }
    }, 1000);
}

public interface OnRefreshListener {

    void onRefresh();

    void onLoadMore();
}

public void setOnRefreshListener(OnRefreshListener listener) {
    mOnRefreshListener = listener;
}
}

布局xml代码：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<include layout="@layout/navi_bar" />

<LinearLayout
    android:id="@+id/page_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <my.widgets.ExListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <include layout="@layout/empty_view" />
</LinearLayout>

先谢谢！

Answer 1

好的，所以按下操作只是在您触摸屏幕时才开始点击。现在我不是专家，但是我会这样做：

    private boolean touch = false;


    @Override public boolean onTouchEvent (MotionEvent ev) {
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                downY = (int) ev.getY();
                touch = true;
                return true;
            case MotionEvent.ACTION_UP:
                if (touch) {
                    touch = false;
                    moveY = (int) ev.getY();
                    diff = (moveY - downY) / 2;
                    //do the rest
                }
                return true;
        }
        return true;
    }
}

我将变量输出到控制台，这给了我正确的downY，moveY和差异。

MotionEvent.ACTION_DOWN在方法onTouchEvent（MotionEvent ev）

1 个答案: