我希望我的应用程序能够识别用户在手机屏幕上从右向左滑动。
如何做到这一点?
当前回答
这个问题仍然存在。添加以下类:
private class SwipeFirstTouchListener implements View.OnTouchListener {
private final DirtyOnSwipeTouchListener swipe;
private final View.OnTouchListener delegate;
private SwipeFirstTouchListener(DirtyOnSwipeTouchListener swipe, View.OnTouchListener delegate) {
this.swipe = swipe;
this.delegate = delegate;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
if (!swipe.onTouch(v, event)) {
// no a swipe, so lets try with the rest of the events
return delegate.onTouch(v, event);
}
return false;
}
}
and
private class DirtyOnSwipeTouchListener extends OnSwipeTouchListener {
private boolean dirty = false;
private OnSwipeTouchListener delegate;
public DirtyOnSwipeTouchListener(Context ctx, OnSwipeTouchListener delegate) {
super(ctx);
this.delegate = delegate;
}
private void reset() {
dirty = false;
}
public void onSwipeTop() {
dirty = true;
delegate.onSwipeTop();
}
public void onSwipeRight() {
dirty = true;
delegate.onSwipeRight();
}
public void onSwipeLeft() {
dirty = true;
delegate.onSwipeLeft();
}
public void onSwipeBottom() {
dirty = true;
delegate.onSwipeBottom();
}
@Override
public boolean onTouch(View v, MotionEvent event) {
try {
super.onTouch(v, event);
return dirty;
} finally {
dirty = false;
}
}
};
还有一个在网上找到的课程:
public class OnSwipeTouchListener implements OnTouchListener {
private static final String TAG = OnSwipeTouchListener.class.getName();
private final GestureDetector gestureDetector;
public OnSwipeTouchListener(Context ctx) {
gestureDetector = new GestureDetector(ctx, new GestureListener());
}
@Override
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
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() - e1.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 exception) {
Log.d(TAG, "Unexpected problem handling swipes, ignoring.", exception);
}
return result;
}
}
public void onSwipeRight() {
// Do nothing
}
public void onSwipeLeft() {
// Do nothing
}
public void onSwipeTop() {
// Do nothing
}
public void onSwipeBottom() {
// Do nothing
}
}
然后添加你自己的OnTouchListener和OnSwipeTouchListener，如下所示:
DirtyOnSwipeTouchListener swipe = new DirtyOnSwipeTouchListener(this, new OnSwipeTouchListener(this) {
public void onSwipeTop() {
// your code here
}
public void onSwipeRight() {
// your code here
}
public void onSwipeLeft() {
// your code here
}
public void onSwipeBottom() {
// your code here
}
});
View.OnTouchListener toggleListener = new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
// your code here
return true;
} else if (event.getAction() == MotionEvent.ACTION_DOWN) {
// your code here
return true;
}
return false;
}
};
SwipeFirstTouchListener swipeFirstTouchListener = new SwipeFirstTouchListener(swipe, toggleListener);
myView.setOnTouchListener(swipeFirstTouchListener);
其他回答
对@Mirek Rusin的回答做了一点修改，现在你可以检测多点触摸了。这段代码在Kotlin上:
class OnSwipeTouchListener(ctx: Context, val onGesture: (gestureCode: Int) -> Unit) : OnTouchListener {
private val SWIPE_THRESHOLD = 200
private val SWIPE_VELOCITY_THRESHOLD = 200
private val gestureDetector: GestureDetector
var fingersCount = 0
fun resetFingers() {
fingersCount = 0
}
init {
gestureDetector = GestureDetector(ctx, GestureListener())
}
override fun onTouch(v: View, event: MotionEvent): Boolean {
if (event.pointerCount > fingersCount) {
fingersCount = event.pointerCount
}
return gestureDetector.onTouchEvent(event)
}
private inner class GestureListener : SimpleOnGestureListener() {
override fun onDown(e: MotionEvent): Boolean {
return true
}
override fun onFling(e1: MotionEvent, e2: MotionEvent, velocityX: Float, velocityY: Float): Boolean {
var result = false
try {
val diffY = e2.y - e1.y
val diffX = e2.x - e1.x
if (Math.abs(diffX) > Math.abs(diffY)) {
if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
if (diffX > 0) {
val gesture = when (fingersCount) {
1 -> Gesture.SWIPE_RIGHT
2 -> Gesture.TWO_FINGER_SWIPE_RIGHT
3 -> Gesture.THREE_FINGER_SWIPE_RIGHT
else -> -1
}
if (gesture > 0) {
onGesture.invoke(gesture)
}
} else {
val gesture = when (fingersCount) {
1 -> Gesture.SWIPE_LEFT
2 -> Gesture.TWO_FINGER_SWIPE_LEFT
3 -> Gesture.THREE_FINGER_SWIPE_LEFT
else -> -1
}
if (gesture > 0) {
onGesture.invoke(gesture)
}
}
resetFingers()
}
} else if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
if (diffY > 0) {
val gesture = when (fingersCount) {
1 -> Gesture.SWIPE_DOWN
2 -> Gesture.TWO_FINGER_SWIPE_DOWN
3 -> Gesture.THREE_FINGER_SWIPE_DOWN
else -> -1
}
if (gesture > 0) {
onGesture.invoke(gesture)
}
} else {
val gesture = when (fingersCount) {
1 -> Gesture.SWIPE_UP
2 -> Gesture.TWO_FINGER_SWIPE_UP
3 -> Gesture.THREE_FINGER_SWIPE_UP
else -> -1
}
if (gesture > 0) {
onGesture.invoke(gesture)
}
}
resetFingers()
}
result = true
} catch (exception: Exception) {
exception.printStackTrace()
}
return result
}
}}
在姿态。SWIPE_RIGHT和其他是唯一的整数标识符的手势，我用它来检测一种手势在我的活动:
rootView?.setOnTouchListener(OnSwipeTouchListener(this, {
gesture -> log(Gesture.parseName(this, gesture))
}))
这里的gesture是一个整型变量它包含了我之前传递的值。
@Mirek Rusin的回答很好。 但是，有一个小bug，需要修复
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() - e1.getX();
if (Math.abs(diffX) > Math.abs(diffY)) {
if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
if (diffX > 0) {
if (getOnSwipeListener() != null) {
getOnSwipeListener().onSwipeRight();
}
} else {
if (getOnSwipeListener() != null) {
getOnSwipeListener().onSwipeLeft();
}
}
result = true;
}
}
else if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
if (diffY > 0) {
if (getOnSwipeListener() != null) {
getOnSwipeListener().onSwipeBottom();
}
} else {
if (getOnSwipeListener() != null) {
getOnSwipeListener().onSwipeTop();
}
}
result = true;
}
有什么不同?我们设置result = true，仅当我们检查了所有的需求(SWIPE_THRESHOLD和SWIPE_VELOCITY_THRESHOLD都是Ok的)。这是重要的，如果我们放弃滑动，如果一些需求没有实现，我们必须做smth在OnSwipeTouchListener的onTouchEvent方法!
你不需要复杂的计算。 这可以通过使用来自GestureDetector类的OnGestureListener接口来完成。
在onFling方法中，你可以像这样检测所有四个方向:
MyGestureListener.java:
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
public class MyGestureListener implements GestureDetector.OnGestureListener{
private static final long VELOCITY_THRESHOLD = 3000;
@Override
public boolean onDown(final MotionEvent e){ return false; }
@Override
public void onShowPress(final MotionEvent e){ }
@Override
public boolean onSingleTapUp(final MotionEvent e){ return false; }
@Override
public boolean onScroll(final MotionEvent e1, final MotionEvent e2, final float distanceX,
final float distanceY){ return false; }
@Override
public void onLongPress(final MotionEvent e){ }
@Override
public boolean onFling(final MotionEvent e1, final MotionEvent e2,
final float velocityX,
final float velocityY){
if(Math.abs(velocityX) < VELOCITY_THRESHOLD
&& Math.abs(velocityY) < VELOCITY_THRESHOLD){
return false;//if the fling is not fast enough then it's just like drag
}
//if velocity in X direction is higher than velocity in Y direction,
//then the fling is horizontal, else->vertical
if(Math.abs(velocityX) > Math.abs(velocityY)){
if(velocityX >= 0){
Log.i("TAG", "swipe right");
}else{//if velocityX is negative, then it's towards left
Log.i("TAG", "swipe left");
}
}else{
if(velocityY >= 0){
Log.i("TAG", "swipe down");
}else{
Log.i("TAG", "swipe up");
}
}
return true;
}
}
用法:
GestureDetector mDetector = new GestureDetector(MainActivity.this, new MyGestureListener());
view.setOnTouchListener(new View.OnTouchListener(){
@Override
public boolean onTouch(final View v, final MotionEvent event){
return mDetector.onTouchEvent(event);
}
});
这个问题很多年前就有人问过了。现在，有一个更好的解决方案:SmartSwipe: https://github.com/luckybilly/SmartSwipe
代码如下所示:
SmartSwipe.wrap(contentView)
.addConsumer(new StayConsumer()) //contentView stay while swiping with StayConsumer
.enableAllDirections() //enable directions as needed
.addListener(new SimpleSwipeListener() {
@Override
public void onSwipeOpened(SmartSwipeWrapper wrapper, SwipeConsumer consumer, int direction) {
//direction:
// 1: left
// 2: right
// 4: top
// 8: bottom
}
})
;
为了添加一个onClick，下面是我所做的。
....
// in OnSwipeTouchListener class
private final class GestureListener extends SimpleOnGestureListener {
.... // normal GestureListener code
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
onClick(); // my method
return super.onSingleTapConfirmed(e);
}
} // end GestureListener class
public void onSwipeRight() {
}
public void onSwipeLeft() {
}
public void onSwipeTop() {
}
public void onSwipeBottom() {
}
public void onClick(){
}
// as normal
@Override
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
} // end OnSwipeTouchListener class
我正在使用Fragments，因此使用getActivity()作为上下文。这就是我实现它的方法——而且它很有效。
myLayout.setOnTouchListener(new OnSwipeTouchListener(getActivity()) {
public void onSwipeTop() {
Toast.makeText(getActivity(), "top", Toast.LENGTH_SHORT).show();
}
public void onSwipeRight() {
Toast.makeText(getActivity(), "right", Toast.LENGTH_SHORT).show();
}
public void onSwipeLeft() {
Toast.makeText(getActivity(), "left", Toast.LENGTH_SHORT).show();
}
public void onSwipeBottom() {
Toast.makeText(getActivity(), "bottom", Toast.LENGTH_SHORT).show();
}
public void onClick(){
Toast.makeText(getActivity(), "clicked", Toast.LENGTH_SHORT).show();
}
});
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