android - 在正常的 Android Activity 上检测滑动

Question

是否有可能在正常的 Android Activity 中检测到用户向左/向右滑动？还是我必须使用 SwipeView？

Answer 1

如果您正在寻找 Xamarin/C# 示例

在您的Activity(或 View )上实现GestureDetector.IOnGestureListener，并在OnFling 方法中计算触摸方向:

[Activity(Label = "Swiper", MainLauncher = true, Icon = "@mipmap/icon")]
public class MainActivity : Activity, GestureDetector.IOnGestureListener
{
    GestureDetector gestureDetector;
    const int SWIPE_DISTANCE_THRESHOLD = 100;
    const int SWIPE_VELOCITY_THRESHOLD = 100;

    public bool OnDown(MotionEvent e)
    {
        return true;
    }

    public bool OnFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
    {
        float distanceX = e2.GetX() - e1.GetX();
        float distanceY = e2.GetY() - e1.GetY();
        if (Math.Abs(distanceX) > Math.Abs(distanceY) && Math.Abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.Abs(velocityX) > SWIPE_VELOCITY_THRESHOLD)
        {
            if (distanceX > 0)
                OnSwipeRight();
            else
                OnSwipeLeft();
            return true;
        }
        return false;
    }

    void OnSwipeLeft()
    {
        Button button = FindViewById<Button>(Resource.Id.myButton);
        button.Text = "Swiped Left";
    }

    void OnSwipeRight()
    {
        Button button = FindViewById<Button>(Resource.Id.myButton);
        button.Text = "Swiped Right";
    }

    public void OnLongPress(MotionEvent e)
    {
    }

    public bool OnScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
    {
        return false;
    }

    public void OnShowPress(MotionEvent e)
    {
    }

    public bool OnSingleTapUp(MotionEvent e)
    {
        return false;
    }

    public bool OnTouch(View v, MotionEvent e)
    {
        return gestureDetector.OnTouchEvent(e);
    }

    public override bool OnTouchEvent(MotionEvent e)
    {
        gestureDetector.OnTouchEvent(e);
        return false;
    }
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.Main);

        gestureDetector = new GestureDetector(this);
    }
}