android - 在 viewpager 内平移的 achartengine

Question

我在 android.support.v4.view.ViewPager 中有一个 achartengine GraphicalView 图表。

我希望我的图表在用户将手指拖到图表上时平移，但现在事件在一个小的拖动 Action 后被 ViewPager 捕获。

我希望能够让用户平移到图表的末尾，然后让 ViewPager 切换页面。作为替代方案，我想至少阻止 ViewPager 捕获图表内的拖动运动。

有什么想法吗？

Answer 1

这是我的解决方案。

它允许用户在图表中有数据时四处拖动图表。之后，拖动事件被 ViewPager 捕获。

就像我说的，关键是这个解决方案是 requestDisallowInterceptTouchEvent功能。

public class ParameterGraphicalView extends org.achartengine.GraphicalView {

// stores the data model size
private int mDataSize = 0;
// stores the first X position in the dataset
private long mDataStartX = 0;
// stores the last X position in the dataset
private long mDataEndX = 0;

// the ViewPager
private ViewParent mViewPager;
//(...)
@Override
public boolean onTouchEvent(MotionEvent event) {

    // save the position of the first touch so we can determine whether the user is dragging
    // left or right
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        mFirstTouchX = event.getX();
    }

    // when mViewPager.requestDisallowInterceptTouchEvent(true), the viewpager does not
    // intercept the events, and the drag events (pan, pinch) are caught by the GraphicalView

    // we want to keep the ViewPager from intercepting the event if:
    // 1- there are 2 or more touches, i.e. the pinch gesture
    // 2- the user is dragging to the left but there is no data to show to the right
    // 3- the user is dragging to the right but there is no data to show to the left
    if (event.getPointerCount() > 1
            || (event.getX() < mFirstTouchX && mDataSize > 0 && mRenderer.getXAxisMax() < mDataEndX)
            || (event.getX() > mFirstTouchX && mData.size() > 0 && mRenderer.getXAxisMin() > mDataStartX)) {
        mViewPager.requestDisallowInterceptTouchEvent(true);
    }
    else {
        mViewPager.requestDisallowInterceptTouchEvent(false);
    }

    return super.onTouchEvent(event);
}
}