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?
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
这段代码检测左右滑动,避免了废弃的API调用,并对之前的答案进行了其他改进。
/**
* Detects left and right swipes across a view.
*/
public class OnSwipeTouchListener implements OnTouchListener {
private final GestureDetector gestureDetector;
public OnSwipeTouchListener(Context context) {
gestureDetector = new GestureDetector(context, new GestureListener());
}
public void onSwipeLeft() {
}
public void onSwipeRight() {
}
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
private final class GestureListener extends SimpleOnGestureListener {
private static final int SWIPE_DISTANCE_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) {
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;
}
}
}
像这样使用它:
view.setOnTouchListener(new OnSwipeTouchListener(context) {
@Override
public void onSwipeLeft() {
// Whatever
}
});
其他回答
因为这个问题有点老,很流行,我试图更新答案,并通过结合答案和评论中的多种建议来改进它。
从Java切换到Kotlin并使用一些Kotlin语法Eyecandy(主观) 使onswipe函数返回它们是否消耗了事件(ruX答案) 从if语句中移除结果赋值并删除变量(直接返回) 仅检测垂直和水平滑动的替代方案 只能检测上、下、右、左的选择。 为保持一致性(方向,而不是位置),将上下重命名为上下。
四个方向都刷:
open class OnSwipeTouchListener(val context: Context?) : OnTouchListener {
companion object {
private const val SwipeThreshold = 100
private const val SwipeVelocityThreshold = 100
}
private val gestureDetector = GestureDetector(context, GestureListener())
override fun onTouch(v: View, event: MotionEvent): Boolean {
return gestureDetector.onTouchEvent(event)
}
open fun onSwipeRight(): Boolean { return false }
open fun onSwipeLeft(): Boolean { return false }
open fun onSwipeUp(): Boolean { return false }
open fun onSwipeDown(): Boolean { return false }
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 {
try {
val diffY = e2.y - e1.y
val diffX = e2.x - e1.x
if (abs(diffX) > abs(diffY)) {
if (abs(diffX) > SwipeThreshold && abs(velocityX) > SwipeVelocityThreshold) {
return when {
diffX > 0 -> onSwipeRight()
else -> onSwipeLeft()
}
}
} else if (abs(diffY) > SwipeThreshold && abs(velocityY) > SwipeVelocityThreshold) {
return when {
diffY > 0 -> onSwipeDown()
else -> onSwipeUp()
}
}
} catch (exception: Exception) {
exception.printStackTrace()
}
return false
}
}
}
用法:
myView.setOnTouchListener(object : OnSwipeTouchListener(context) {
// Implement any function you need:
override fun onSwipeUp(): Boolean {
Toast.makeText(context, "UP", Toast.LENGTH_SHORT).show()
return true
}
override fun onSwipeLeft(): Boolean {
Toast.makeText(context, "LEFT", Toast.LENGTH_SHORT).show()
return true
}
})
onFling()的替代方案
替代方案删除更多代码并重新排序检查。重新排序是没有必要的,但我认为它看起来更整洁,更容易理解。 代码将放在try括号中。用法保持不变,只是实现各自的onSwipe函数
水平
val diffY = e2。Y - e1。Y 返回if (abs(velocityY) > SwipeVelocityThreshold) { 当{ > SwipeThreshold -> onSwipeDown() diffY < - swipethreshold -> onSwipeUp() Else -> false } }其他false
垂直
val diffX = e2。X - e1。X 返回if (abs(velocityX) > SwipeVelocityThreshold) { 当{ > SwipeThreshold -> onSwipeRight() diffX < - swipethreshold -> onSwipeLeft() Else -> false } }其他false
一个方向
"up"的例子
val diffY = e2。Y - e1。Y 返回{ diffY < - swipethreshold -> onSwipeUp() Else -> false }
Additional Notes: In (ruX answer) they discussed removing onDown to also detect an onClickListener for the same view. However, when I removed onDown, the class did not work anymore. I don't exactly know why. I looked into the code of GestureDetector but it is very complex and the consequences of the return value of onDown seems to have some implications. So I left it in. Also, you can just use SimpleOnGestureListener.onSingleTapUp() just like you did onFling and create a onClick() function that is called there.
版本信息:
compileSdkVersion 31 minSdkVersion 24 targetSdkVersion 31
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);
}
});
我知道从2012年开始有点晚了,但我希望它能帮助到一些人,因为我认为它比大多数答案都更短,更干净:
view.setOnTouchListener((v, event) -> {
int action = MotionEventCompat.getActionMasked(event);
switch(action) {
case (MotionEvent.ACTION_DOWN) :
Log.d(DEBUG_TAG,"Action was DOWN");
return true;
case (MotionEvent.ACTION_MOVE) :
Log.d(DEBUG_TAG,"Action was MOVE");
return true;
case (MotionEvent.ACTION_UP) :
Log.d(DEBUG_TAG,"Action was UP");
return true;
case (MotionEvent.ACTION_CANCEL) :
Log.d(DEBUG_TAG,"Action was CANCEL");
return true;
case (MotionEvent.ACTION_OUTSIDE) :
Log.d(DEBUG_TAG,"Movement occurred outside bounds " +
"of current screen element");
return true;
default :
return super.onTouchEvent(event);
}
});
当然,你可以只留下相关的手势。
src: https://developer.android.com/training/gestures/detector
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
}
})
;
@Edward Brey的方法很有效。如果有人也想复制和粘贴导入的OnSwipeTouchListener,他们是:
import android.content.Context;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;