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
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
/**
* Detects left and right swipes across a view.
*/
class OnSwipeTouchListener(context: Context, onSwipeCallBack: OnSwipeCallBack?) : OnTouchListener {
private var gestureDetector : GestureDetector
private var onSwipeCallBack: OnSwipeCallBack?=null
init {
gestureDetector = GestureDetector(context, GestureListener())
this.onSwipeCallBack = onSwipeCallBack!!
}
companion object {
private val SWIPE_DISTANCE_THRESHOLD = 100
private val SWIPE_VELOCITY_THRESHOLD = 100
}
/* fun onSwipeLeft() {}
fun onSwipeRight() {}*/
override fun onTouch(v: View, event: MotionEvent): Boolean {
return gestureDetector.onTouchEvent(event)
}
private inner class GestureListener : SimpleOnGestureListener() {
override fun onDown(e: MotionEvent): Boolean {
return true
}
override fun onFling(eve1: MotionEvent?, eve2: MotionEvent?, velocityX: Float, velocityY: Float): Boolean {
try {
if(eve1 != null&& eve2!= null) {
val distanceX = eve2?.x - eve1?.x
val distanceY = eve2?.y - eve1?.y
if (Math.abs(distanceX) > Math.abs(distanceY) && Math.abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
if (distanceX > 0)
onSwipeCallBack!!.onSwipeLeftCallback()
else
onSwipeCallBack!!.onSwipeRightCallback()
return true
}
}
}catch (exception:Exception){
exception.printStackTrace()
}
return false
}
}
}
其他回答
爱德华·布雷的回答在科特林的使用
view.setOnTouchListener(object: OnSwipeTouchListener(this) {
override fun onSwipeLeft() {
super.onSwipeLeft()
}
override fun onSwipeRight() {
super.onSwipeRight()
}
}
)
@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!
使用SwipeListView，让它为你处理手势检测。
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。
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();
}
});
推荐文章
- 警告:API ' variable . getjavacompile()'已过时，已被' variable . getjavacompileprovider()'取代
- 安装APK时出现错误
- 碎片中的onCreateOptionsMenu
- TextView粗体通过XML文件?
- 如何使线性布局的孩子之间的空间?
- DSL元素android.dataBinding。enabled'已过时，已被'android.buildFeatures.dataBinding'取代
- ConstraintLayout:以编程方式更改约束
- PANIC: AVD系统路径损坏。检查ANDROID_SDK_ROOT值
- 如何生成字符串类型的buildConfigField
- Recyclerview不调用onCreateViewHolder
- Android API 21工具栏填充
- Android L中不支持操作栏导航模式
- 如何在TextView中添加一个子弹符号?
- PreferenceManager getDefaultSharedPreferences在Android Q中已弃用
- 在Android Studio中创建aar文件
