我正在尝试在 Android fragment 上检测到左、右、上和下滑动。使用几个在线资源，例如这个很棒的 answer在 Stackoverflow 上，我现在可以检测到上下滑动。但是，它不适用于左右滑动。
OnSwipeListener.java:
// Detects left and right swipes across a view
public class OnSwipeTouchListener implements View.OnTouchListener {
// https://developer.android.com/reference/android/view/GestureDetector
private final GestureDetector gestureDetector;
public OnSwipeTouchListener(Context context) {
this.gestureDetector = new GestureDetector(context, new GestureListener());
}
// from View.onTouchListener class
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
return gestureDetector.onTouchEvent(motionEvent);
}
private final class GestureListener extends GestureDetector.SimpleOnGestureListener {
private static final int SWIPE_THRESHOLD = 100;
private static final int SWIPE_VELOCITY_THRESHOLD = 100;
@Override
public boolean onDown(MotionEvent e) {
return true;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
boolean result = false;
try {
float diffY = e2.getY() - e1.getY();
float diffX = e2.getX() - e2.getX();
if(Math.abs(diffX) > Math.abs(diffY)) {
if(Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
if(diffX > 0) {
onSwipeRight();
}else {
onSwipeLeft();
}
result = true;
}
} else if(Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
if(diffY > 0) {
onSwipeBottom();
} else {
onSwipeTop();
}
result = true;
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
}
public void onSwipeRight() {
}
public void onSwipeLeft() {
}
public void onSwipeTop() {
}
public void onSwipeBottom() {
}
}
然后我在 MyFragment.java 的 onCreateView 方法中使用这些方法:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.myfragment_layout, container, false);
v.setOnTouchListener(new OnSwipeTouchListener(getActivity()) {
public void onSwipeTop() {
Toast.makeText(getActivity(), "TOP SWIPE", Toast.LENGTH_SHORT).show();
}
public void onSwipeRight() {
Toast.makeText(getActivity(), "RIGHT SWIPE", Toast.LENGTH_SHORT).show();
//go back to landing page
// Intent intent = new Intent (getApplicationContext(), MainScreen.class);
// startActivity (intent);
}
public void onSwipeLeft() {
Toast.makeText(getActivity(), "LEFT SWIPE", Toast.LENGTH_SHORT).show();
}
public void onSwipeBottom() {
Toast.makeText(getActivity(), "BOTTOM SWIPE", Toast.LENGTH_SHORT).show();
}
});
return v;
}
如有任何帮助，我们将不胜感激。谢谢。
最佳答案
我认为这行是错误的:
float diffX = e2.getX() - e2.getX();
应该是
float diffX = e2.getX() - e1.getX();
关于android - 检测 Fragment 上的左右滑动，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/51481111/