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
我一直在做类似的事情，但仅限于水平滑动
import android.content.Context
import android.view.GestureDetector
import android.view.MotionEvent
import android.view.View
abstract class OnHorizontalSwipeListener(val context: Context) : View.OnTouchListener {
companion object {
const val SWIPE_MIN = 50
const val SWIPE_VELOCITY_MIN = 100
}
private val detector = GestureDetector(context, GestureListener())
override fun onTouch(view: View, event: MotionEvent) = detector.onTouchEvent(event)
abstract fun onRightSwipe()
abstract fun onLeftSwipe()
private inner class GestureListener : GestureDetector.SimpleOnGestureListener() {
override fun onDown(e: MotionEvent) = true
override fun onFling(e1: MotionEvent, e2: MotionEvent, velocityX: Float, velocityY: Float)
: Boolean {
val deltaY = e2.y - e1.y
val deltaX = e2.x - e1.x
if (Math.abs(deltaX) < Math.abs(deltaY)) return false
if (Math.abs(deltaX) < SWIPE_MIN
&& Math.abs(velocityX) < SWIPE_VELOCITY_MIN) return false
if (deltaX > 0) onRightSwipe() else onLeftSwipe()
return true
}
}
}
然后它可以用于视图组件
private fun listenHorizontalSwipe(view: View) {
view.setOnTouchListener(object : OnHorizontalSwipeListener(context!!) {
override fun onRightSwipe() {
Log.d(TAG, "Swipe right")
}
override fun onLeftSwipe() {
Log.d(TAG, "Swipe left")
}
}
)
}
其他回答
我一直在做类似的事情，但仅限于水平滑动
import android.content.Context
import android.view.GestureDetector
import android.view.MotionEvent
import android.view.View
abstract class OnHorizontalSwipeListener(val context: Context) : View.OnTouchListener {
companion object {
const val SWIPE_MIN = 50
const val SWIPE_VELOCITY_MIN = 100
}
private val detector = GestureDetector(context, GestureListener())
override fun onTouch(view: View, event: MotionEvent) = detector.onTouchEvent(event)
abstract fun onRightSwipe()
abstract fun onLeftSwipe()
private inner class GestureListener : GestureDetector.SimpleOnGestureListener() {
override fun onDown(e: MotionEvent) = true
override fun onFling(e1: MotionEvent, e2: MotionEvent, velocityX: Float, velocityY: Float)
: Boolean {
val deltaY = e2.y - e1.y
val deltaX = e2.x - e1.x
if (Math.abs(deltaX) < Math.abs(deltaY)) return false
if (Math.abs(deltaX) < SWIPE_MIN
&& Math.abs(velocityX) < SWIPE_VELOCITY_MIN) return false
if (deltaX > 0) onRightSwipe() else onLeftSwipe()
return true
}
}
}
然后它可以用于视图组件
private fun listenHorizontalSwipe(view: View) {
view.setOnTouchListener(object : OnHorizontalSwipeListener(context!!) {
override fun onRightSwipe() {
Log.d(TAG, "Swipe right")
}
override fun onLeftSwipe() {
Log.d(TAG, "Swipe left")
}
}
)
}
如果你还需要处理点击事件，这里做一些修改:
public class OnSwipeTouchListener implements OnTouchListener {
private final GestureDetector gestureDetector = new GestureDetector(new GestureListener());
public boolean onTouch(final View v, final MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
private final class GestureListener extends SimpleOnGestureListener {
private static final int SWIPE_THRESHOLD = 100;
private static final int SWIPE_VELOCITY_THRESHOLD = 100;
@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) {
result = onSwipeRight();
} else {
result = onSwipeLeft();
}
}
} else {
if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
if (diffY > 0) {
result = onSwipeBottom();
} else {
result = onSwipeTop();
}
}
}
} catch (Exception exception) {
exception.printStackTrace();
}
return result;
}
}
public boolean onSwipeRight() {
return false;
}
public boolean onSwipeLeft() {
return false;
}
public boolean onSwipeTop() {
return false;
}
public boolean onSwipeBottom() {
return false;
}
}
以及示例用法:
background.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
toggleSomething();
}
});
background.setOnTouchListener(new OnSwipeTouchListener() {
public boolean onSwipeTop() {
Toast.makeText(MainActivity.this, "top", Toast.LENGTH_SHORT).show();
return true;
}
public boolean onSwipeRight() {
Toast.makeText(MainActivity.this, "right", Toast.LENGTH_SHORT).show();
return true;
}
public boolean onSwipeLeft() {
Toast.makeText(MainActivity.this, "left", Toast.LENGTH_SHORT).show();
return true;
}
public boolean onSwipeBottom() {
Toast.makeText(MainActivity.this, "bottom", Toast.LENGTH_SHORT).show();
return true;
}
});
@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!
OnSwipeTouchListener.java:
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;
public class OnSwipeTouchListener implements OnTouchListener {
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 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) {
exception.printStackTrace();
}
return result;
}
}
public void onSwipeRight() {
}
public void onSwipeLeft() {
}
public void onSwipeTop() {
}
public void onSwipeBottom() {
}
}
用法:
imageView.setOnTouchListener(new OnSwipeTouchListener(MyActivity.this) {
public void onSwipeTop() {
Toast.makeText(MyActivity.this, "top", Toast.LENGTH_SHORT).show();
}
public void onSwipeRight() {
Toast.makeText(MyActivity.this, "right", Toast.LENGTH_SHORT).show();
}
public void onSwipeLeft() {
Toast.makeText(MyActivity.this, "left", Toast.LENGTH_SHORT).show();
}
public void onSwipeBottom() {
Toast.makeText(MyActivity.this, "bottom", Toast.LENGTH_SHORT).show();
}
});
扩展Mirek的回答，当你想在滚动视图中使用滑动手势时。默认情况下，滚动视图的触摸监听器被禁用，因此滚动动作不会发生。为了解决这个问题，您需要重写Activity的dispatchTouchEvent方法，并在您完成自己的侦听器后返回该方法的继承版本。
为了对Mirek的代码做一些修改: 我在OnSwipeTouchListener中添加了一个gestureDetector getter。
public GestureDetector getGestureDetector(){
return gestureDetector;
}
在Activity中声明OnSwipeTouchListener作为类范围的字段。
OnSwipeTouchListener onSwipeTouchListener;
相应修改用法代码:
onSwipeTouchListener = new OnSwipeTouchListener(MyActivity.this) {
public void onSwipeTop() {
Toast.makeText(MyActivity.this, "top", Toast.LENGTH_SHORT).show();
}
public void onSwipeRight() {
Toast.makeText(MyActivity.this, "right", Toast.LENGTH_SHORT).show();
}
public void onSwipeLeft() {
Toast.makeText(MyActivity.this, "left", Toast.LENGTH_SHORT).show();
}
public void onSwipeBottom() {
Toast.makeText(MyActivity.this, "bottom", Toast.LENGTH_SHORT).show();
}
});
imageView.setOnTouchListener(onSwipeTouchListener);
并覆盖活动内部的dispatchTouchEvent方法:
@Override
public boolean dispatchTouchEvent(MotionEvent ev){
swipeListener.getGestureDetector().onTouchEvent(ev);
return super.dispatchTouchEvent(ev);
}
现在滚动和滑动动作都可以工作了。
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