我的问题：我如何检测用户何时向上/向下和向左/向右移动手指（以及我如何知道他们的手指移动了这些组的哪个方向）？
我的情况：我想在他们上下移动手指时更改我的应用程序的亮度（向上 = 更亮，向下 = 更暗），并且我想在活动之间切换和/或根据他们的左/右滑动查看视图。
【问题讨论】：
标签： android user-interface user-interaction
我为此写了一个简单的类：它有据可查，所以我不会在这里解释它
public class OnSwipeListener extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
// Grab two events located on the plane at e1=(x1, y1) and e2=(x2, y2)
// Let e1 be the initial event
// e2 can be located at 4 different positions, consider the following diagram
// (Assume that lines are separated by 90 degrees.)
//
//
// \ A /
// \ /
// D e1 B
// / \
// / C \
//
// So if (x2,y2) falls in region:
// A => it's an UP swipe
// B => it's a RIGHT swipe
// C => it's a DOWN swipe
// D => it's a LEFT swipe
//
float x1 = e1.getX();
float y1 = e1.getY();
float x2 = e2.getX();
float y2 = e2.getY();
Direction direction = getDirection(x1,y1,x2,y2);
return onSwipe(direction);
}
/** Override this method. The Direction enum will tell you how the user swiped. */
public boolean onSwipe(Direction direction){
return false;
}
/**
* Given two points in the plane p1=(x1, x2) and p2=(y1, y1), this method
* returns the direction that an arrow pointing from p1 to p2 would have.
* @param x1 the x position of the first point
* @param y1 the y position of the first point
* @param x2 the x position of the second point
* @param y2 the y position of the second point
* @return the direction
*/
public Direction getDirection(float x1, float y1, float x2, float y2){
double angle = getAngle(x1, y1, x2, y2);
return Direction.fromAngle(angle);
}
/**
*
* Finds the angle between two points in the plane (x1,y1) and (x2, y2)
* The angle is measured with 0/360 being the X-axis to the right, angles
* increase counter clockwise.
*
* @param x1 the x position of the first point
* @param y1 the y position of the first point
* @param x2 the x position of the second point
* @param y2 the y position of the second point
* @return the angle between two points
*/
public double getAngle(float x1, float y1, float x2, float y2) {
double rad = Math.atan2(y1-y2,x2-x1) + Math.PI;
return (rad*180/Math.PI + 180)%360;
}
public enum Direction{
up,
down,
left,
right;
/**
* Returns a direction given an angle.
* Directions are defined as follows:
*
* Up: [45, 135]
* Right: [0,45] and [315, 360]
* Down: [225, 315]
* Left: [135, 225]
*
* @param angle an angle from 0 to 360 - e
* @return the direction of an angle
*/
public static Direction fromAngle(double angle){
if(inRange(angle, 45, 135)){
return Direction.up;
}
else if(inRange(angle, 0,45) || inRange(angle, 315, 360)){
return Direction.right;
}
else if(inRange(angle, 225, 315)){
return Direction.down;
}
else{
return Direction.left;
}
}
/**
* @param angle an angle
* @param init the initial bound
* @param end the final bound
* @return returns true if the given angle is in the interval [init, end).
*/
private static boolean inRange(double angle, float init, float end){
return (angle >= init) && (angle < end);
}
}
}
要使用，只需扩展 OnSwipeListener 并覆盖 onSwipe 方法
【讨论】：
onSwipe，请将其和类标记为abstract。
您只需扩展 SimpleOnGestureListener 类，
在你的课堂上声明，
private static final int SWIPE_MIN_DISTANCE = 120;
private static final int SWIPE_MAX_OFF_PATH = 250;
private static final int SWIPE_THRESHOLD_VELOCITY = 200;
作为水平滑动的示例，您可以查看以下代码，
class MyGestureDetector extends SimpleOnGestureListener {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
try {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH){
return false;
}
// right to left swipe
if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
onLeftSwipe();
}
// left to right swipe
else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
onRightSwipe();
}
} catch (Exception e) {
}
return false;
}
}
您可以类似地执行此操作以达到垂直滑动的目的。
【讨论】：
Fernandour 答案很完美，我正在写这个答案，说明如何将它与 Activity 和 Fragment 一起使用，因为很多人都在寻找它。
public class MyActivity extends Activity implements View.OnTouchListener{
private RelativeLayout someLayout;
//take any layout on which you want your gesture listener;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
gestureDetector=new GestureDetector(this,new OnSwipeListener(){
@Override
public boolean onSwipe(Direction direction) {
if (direction==Direction.up){
//do your stuff
Log.d(TAG, "onSwipe: up");
}
if (direction==Direction.down){
//do your stuff
Log.d(TAG, "onSwipe: down");
}
return true;
}
});
someLayout.setOnTouchListener(this);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
Log.d(TAG, "onTouch: ");
gestureDetector.onTouchEvent(event);
return true;
}
}
【讨论】：
上面fernandohur answer的完整使用示例：
如果您想将 OnSwipeListener 应用于您的一个视图，那么：
无论此视图在哪里 - 为该视图设置一个触摸侦听器，如下所示：
myview.setOnTouchListener(this);
现在在 Activity 的 OnCreate 或自定义视图构造函数中执行以下操作：
// Global
private GestureDetectorCompat detector;
// In OnCreate or custome view constructor (which extends one of Android views)
detector = new GestureDetectorCompat(context, onSwipeListener);
在同一个类中重写 onTouch 事件，如下所示：
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
return detector.onTouchEvent(motionEvent);
}
并且在同一个类中也有这个监听器对象：
OnSwipeListener onSwipeListener = new OnSwipeListener() {
@Override
public boolean onSwipe(Direction direction) {
// Possible implementation
if(direction == Direction.left|| direction == Direction.right) {
// Do something COOL like animation or whatever you want
// Refer to your view if needed using a global reference
return true;
}
else if(direction == Direction.up|| direction == Direction.down) {
// Do something COOL like animation or whatever you want
// Refer to your view if needed using a global reference
return true;
}
return super.onSwipe(direction);
}
};
【讨论】：
我就是这样做的，最简单的方法
float initialX, initialY;
@Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getActionMasked();
switch (action) {
case MotionEvent.ACTION_DOWN:
initialX = event.getX();
initialY = event.getY();
// Log.d(TAG, "Action was DOWN");
break;
case MotionEvent.ACTION_MOVE:
//Log.d(TAG, "Action was MOVE");
break;
case MotionEvent.ACTION_UP:
float finalX = event.getX();
float finalY = event.getY();
//Log.d(TAG, "Action was UP");
if (initialX < finalX) {
// Log.d(TAG, "Left to Right swipe performed");
}
if (initialX > finalX) {
// Log.d(TAG, "Right to Left swipe performed");
}
if (initialY < finalY) {
// Log.d(TAG, "Up to Down swipe performed");
}
if (initialY > finalY) {
// Log.d(TAG, "Down to Up swipe performed");
}
break;
case MotionEvent.ACTION_CANCEL:
//Log.d(TAG,"Action was CANCEL");
break;
case MotionEvent.ACTION_OUTSIDE:
// Log.d(TAG, "Movement occurred outside bounds of current screen element");
break;
}
return super.onTouchEvent(event);
}
【讨论】：
我测试了几次并且对我有用的最佳答案
float firstX_point, firstY_point;
@Override
public boolean onTouchEvent(MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
firstX_point = event.getRawX();
firstY_point = event.getRawY();
break;
case MotionEvent.ACTION_UP:
float finalX = event.getRawX();
float finalY = event.getRawY();
int distanceX = (int) (finalX - firstX_point);
int distanceY = (int) (finalY - firstY_point);
if (Math.abs(distanceX) > Math.abs(distanceY)) {
if ((firstX_point < finalX)) {
Log.d("Test", "Left to Right swipe performed");
} else {
Log.d("Test", "Right to Left swipe performed");
}
}else{
if ((firstY_point < finalY)) {
Log.d("Test", "Up to Down swipe performed");
} else {
Log.d("Test", "Down to Up swipe performed");
}
}
break;
}
return true;
}
【讨论】：
您可以覆盖 SimpleGestureListener 并计算起点和终点当前坐标之间的差异：
private class GestureListener extends SimpleOnGestureListener {
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
if (e2.getY() > e1.getY()) {
// direction up
}else {
// direction down
}
if (e2.getX() > e1.getX()) {
// direction right
}else {
// direction left
}
return true;
}
}
【讨论】：
我是这样解决的：
viewPager.setOnTouchListener(new View.OnTouchListener() {
float prevX = -1;
@Override
public boolean onTouch(View v, MotionEvent event) {
if (prevX != -1) {
if (event.getX() > prevX) {
if (viewPager.getCurrentItem() == 0) {
// Left to Right swipe
}
//Log.d("DEBUG", MotionEvent.ACTION_MOVE + ":" + event.getAction() + ":" + event.getActionMasked() + ":Left Swipe" + ":" + prevX + ":" + event.getX() + ":" + viewPager.getCurrentItem());
} else if (prevX > event.getX()) {
// Right to left swipe
//Log.d("DEBUG", MotionEvent.ACTION_MOVE + ":" + event.getAction() + ":" + event.getActionMasked() + ":Right Swipe" + ":" + prevX + ":" + event.getX() + ":" + viewPager.getCurrentItem());
}
}
if (event.getAction() == MotionEvent.ACTION_MOVE) {
prevX = event.getX();
} else {
prevX = -1;
}
return false;
}
});
【讨论】：
对于这样一个简单的问题，可用的答案太复杂了。 我建议另一种方法（代码是as3，但你可以理解）：
var touchDistance:Number = Point.distance(_moveTouchPoint, _startTouchPoint);
if (touchDistance >= SWIPE_MIN_DISTANCE)
{
var xDiff:Number = _moveTouchPoint.x - _startTouchPoint.x;
var yDiff:Number = _moveTouchPoint.y - _startTouchPoint.y;
var yGreater:Boolean = Math.abs(yDiff) >= Math.abs(xDiff);
if (yGreater)
{
// direction is up or down
changePlayerDirectionTo(yDiff < 0 ? DIRECTION_UP : DIRECTION_DOWN);
}
else
{
// direction is left or right
changePlayerDirectionTo(xDiff < 0 ? DIRECTION_LEFT : DIRECTION_RIGHT)
}
}
在每种情况下，x 或 y 的绝对值都会更大，这可以解决特定的方向集。从此您可以依靠坐标符号来准确检测哪个方向。
【讨论】：
我在 bitbucket 上有一个开源手势库可以做到这一点。这个库中有一个“HGFling”类。这演示了如何检测投掷的方向。您可以从以下位置下载库：https://bitbucket.org/warwick/hacergestov3。它是开源的。
【讨论】：
为 @Fernandour 答案添加 Kotlin 实现。对于 Java，请查看 @farhan patel 答案
我添加这个是因为我遇到了困难，希望它能节省一些人的时间。
class ClientFragment : Fragment(), View.OnTouchListener {
private lateinit var gestureDetector: GestureDetector
override fun onTouch(v: View?, event: MotionEvent?): Boolean {
Log.d(TAG, "onTouch: ");
gestureDetector.onTouchEvent(event);
return true
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
...
gestureDetector = GestureDetector(activity, object : OnSwipeListener() {
override fun onSwipe(direction: Direction): Boolean {
when(direction){
Direction.up ->
{
Log.d(TAG, "onSwipe: up")
sendCommand("UP")
return true
}
Direction.down ->{
Log.d(TAG, "onSwipe: down")
sendCommand("DOWN")
return true
}
Direction.left ->
{
Log.d(TAG, "onSwipe: left")
sendCommand("LEFT")
return true
}
Direction.right ->{
Log.d(TAG, "onSwipe: right")
sendCommand("RIGHT")
return true
}
else -> {
}
}
return true
}
})
dpadLayout.setOnTouchListener(this)
【讨论】：
扩展版 @Fernandour 的答案很容易实现直接与触摸监听器没有做额外的代码......触摸点，长按，双击实现......。
public class OnSwipeListener implements View.OnTouchListener{
public enum Direction{up,down,left,right;}
private GestureDetector gestureDetector;
private Context context;
public OnSwipeListener(Context c) {
this.context = c;
gestureDetector = new GestureDetector(c, new GestureListener(c));
}
public boolean onTouch(final View view, final MotionEvent motionEvent) {
return gestureDetector.onTouchEvent(motionEvent);
}
public void onSwipeRight() {
}
public void onSwipeLeft() {
}
public void onSwipeUp() {
}
public void onSwipeDown() {
}
public void onClick() {
}
public void onDoubleClick() {
}
public void onLongClick() {
}
public double getAngle(float x1, float y1, float x2, float y2) {
double rad = Math.atan2(y1-y2,x2-x1) + Math.PI;
return (rad*180/Math.PI + 180)%360;
}
private final class GestureListener extends GestureDetector.SimpleOnGestureListener {
Context context;
public GestureListener(Context c) {
this.context = c;
}
@Override
public boolean onDown(MotionEvent e) {
return true;
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
onClick();
return super.onSingleTapUp(e);
}
@Override
public boolean onDoubleTap(MotionEvent e) {
onDoubleClick();
return super.onDoubleTap(e);
}
@Override
public void onLongPress(MotionEvent e) {
onLongClick();
super.onLongPress(e);
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
float x1 = e1.getX();
float y1 = e1.getY();
float x2 = e2.getX();
float y2 = e2.getY();
Direction direction = getDirection(x1,y1,x2,y2);
return onSwipe(direction);
}
public Direction getDirection(float x1, float y1, float x2, float y2){
double angle = getAngle(x1, y1, x2, y2);
return fromAngle(angle);
}
public Direction fromAngle(double angle){
if(inRange(angle, 45, 135)){
onSwipeUp();
return Direction.up;
}
else if(inRange(angle, 0,45) || inRange(angle, 315, 360)){
onSwipeRight();
return Direction.right;
}
// else if(inRange(angle, 225, 315)){
// //onSwipeDown();
//
// }
else if(inRange(angle,135, 225)){
onSwipeLeft();
return Direction.left;
}
else {
return Direction.down;
}
}
private boolean inRange(double angle, float init, float end){
return (angle >= init) && (angle < end);
}
public boolean onSwipe(Direction direction){
return false;
}
};
}
【讨论】：
检测向左、向右、上、下滑动的最佳方法和简单方法
View.OnTouchListener 在该类中添加以下代码： public class OnSwipeTouchListener implements View.OnTouchListener {
private final GestureDetector gestureDetector;
Context context;
OnSwipeTouchListener(Context ctx, View mainView) {
gestureDetector = new GestureDetector(ctx, new GestureListener());
mainView.setOnTouchListener(this);
context = ctx;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
public 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) {
exception.printStackTrace();
}
return result;
}
}
void onSwipeRight() {
Toast.makeText(context, "You Swipe Right", Toast.LENGTH_SHORT).show();
this.onSwipe.swipeRight();
}
void onSwipeLeft() {
Toast.makeText(context, "You Swipe Left", Toast.LENGTH_SHORT).show();
this.onSwipe.swipeLeft();
}
void onSwipeTop() {
Toast.makeText(context, "You Swipe Up", Toast.LENGTH_SHORT).show();
this.onSwipe.swipeTop();
}
void onSwipeBottom() {
Toast.makeText(context, "You Swipe Down", Toast.LENGTH_SHORT).show();
this.onSwipe.swipeBottom();
}
interface onSwipeListener {
void swipeRight();
void swipeTop();
void swipeBottom();
void swipeLeft();
}
onSwipeListener onSwipe;
}
并在您的 MainActivity 类中使用此代码：
public class MainActivity extends AppCompatActivity {
OnSwipeTouchListener onSwipeTouchListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
onSwipeTouchListener = new OnSwipeTouchListener(this, findViewById(R.id.relativeLayout));
}
}
在activity_main.xml:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/relativeLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
tools:context=".MainActivity">
</RelativeLayout>
【讨论】：