我想在连续向上滑动/向下滑动事件中增加/减少一个数字。 我可以使用 GestureDetector 和 OnSwipeTouchListener 实现简单的滑动事件。
但是，只有在滑动后抬起手指时才会感应到此滑动事件。 因此，要将数字增加到 +5，我必须在屏幕上进行 5 次单独向上滑动。
我想应用类似“滑块”的操作，以便在用户在屏幕上的任意位置向上或向下滑动时更改数字。 （我不想使用“滑块”小部件）。
这可能吗？
任何帮助将不胜感激。 谢谢！
【问题讨论】：
标签： android
使用 OnTouchListener：
private float baseX, baseY;
OnTouchListener listener = new OnTouchListener(){
public boolean onTouch (View v, MotionEvent event)
{
switch(event.getAction())
{
case MotionEvent.ACTION_DOWN:
//TOUCH STARTED
baseX = event.getX();
baseY = event.getY();
return true;
case MotionEvent.ACTION_MOVE:
//FINGER IS MOVING
//Do your calculations here, using the x and y positions relative to the starting values you get in ACTION_DOWN
return true;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
//TOUCH COMPLETED
return true;
}
}
}
【讨论】：
@1up，非常感谢您的解决方案！
我可以添加的一项增强功能是，即使在不抬起手指的情况下反转滑动方向，它也能正常工作。
使用您提供的骨架，发布我的代码，希望将来能对某人有所帮助...
public class OnSwipeListener implements OnTouchListener
{
@Override
public boolean onTouch(View v, MotionEvent event)
{
boolean result = false;
float currentX = 0.0f;
float currentY = 0.0f;
float current_diffX = 0.0f;
float current_diffY = 0.0f;
switch(event.getAction())
{
case MotionEvent.ACTION_DOWN:
//Touch detected, record base X-Y coordinates
baseX = event.getX();
baseY = event.getY();
//As the event is consumed, return true
result = true;
break;
case MotionEvent.ACTION_MOVE:
//Swipe started, get current X-Y coordinates and compute those with the base ones
currentX = event.getX();
currentY = event.getY();
current_diffX = currentX - baseX;
current_diffY = currentY - baseY;
//...................................................Determine horizontal swipe direction
if(h_swipe == LEFT_SWIPE)
{
if( currentX > previousX )
{
//If here, then horizontal swipe has been reversed
h_swipe = RIGHT_SWIPE;
//Overwrite base coordinate
baseX = previousX;
//Recalculate Difference
current_diffX = currentX - baseX;
}
else
{
//NOP - Intentionally kept empty
}
}
else if(h_swipe == RIGHT_SWIPE)
{
if( currentX < previousX )
{
//If here, then horizontal swipe has been reversed
h_swipe = LEFT_SWIPE;
//Overwrite base coordinate
baseX = previousX;
//Recalculate Difference
current_diffX = currentX - baseX;
}
else
{
//NOP - Intentionally kept empty
}
}
else
{
//If here, then it's a fresh swipe event, so compare with base coordinates
if( currentX < baseX )
{
h_swipe = LEFT_SWIPE;
}
else if( currentX > baseX )
{
h_swipe = RIGHT_SWIPE;
}
else
{
//NOP - Intentionally kept empty
}
}
//...................................................Determine vertical swipe direction
if(v_swipe == UP_SWIPE)
{
if(currentY > previousY)
{
//If here, then vertical swipe has been reversed
v_swipe = DOWN_SWIPE;
//Overwrite base coordinate
baseY = previousY;
//Recalculate coordinate difference
current_diffY = currentY - baseY;
}
else
{
//NOP - Intentionally kept empty
}
}
else if(v_swipe == DOWN_SWIPE)
{
if(currentY < previousY)
{
//If here, then vertical swipe has been reversed
v_swipe = UP_SWIPE;
//Overwrite base coordinate
baseY = previousY;
//Recalculate coordinate difference
current_diffY = currentY - baseY;
}
else
{
//NOP - Intentionally kept empty
}
}
else
{
//If here, then it's a fresh swipe event, so compare with base coordinates
if( currentY < baseY )
{
v_swipe = UP_SWIPE;
}
else if( currentY > baseY )
{
v_swipe = DOWN_SWIPE;
}
else
{
//NOP - Intentionally kept empty
}
}
//Record current coordinates for future comparisons
previousX = currentX;
previousY = currentY;
//................................Determine the prominent swipe (horizontal/vertical)
if(Math.abs(current_diffX) > Math.abs(current_diffY))
{
//It's a horizontal swipe
if (Math.abs(current_diffX) > SWIPE_THRESHOLD)
{
if (current_diffX > 0)
{
onRightSwipe();
}
else
{
onLeftSwipe();
}
}
else
{
//Not enough swipe movement, ignore.
//NOP - Intentionally kept empty
}
}
else
{
//It's a vertical swipe
if (Math.abs(current_diffY) > SWIPE_THRESHOLD)
{
if (current_diffY > 0)
{
onDownSwipe();
}
else
{
onUpSwipe();
}
}
else
{
//Not enough swipe movement, ignore.
//NOP - Intentionally kept empty
}
}
//As the event is consumed, return true
result = true;
break;
case MotionEvent.ACTION_UP:
//Swipe ended, clear variables, if necessary
h_swipe = NO_H_SWIPE;
v_swipe = NO_V_SWIPE;
baseX = 0.0f;
baseY = 0.0f;
previousX = 0.0f;
previousY = 0.0f;
//As the event is consumed, return true
result = true;
break;
default:
//Do not consume event
result = false;
break;
}
return result;
}
public void onUpSwipe()
{
}
public void onDownSwipe()
{
}
public void onRightSwipe()
{
}
public void onLeftSwipe()
{
}
}
【讨论】：
所以我写了我自己版本的方向监听器。
注意：它会告诉您在连续触摸会话上的滑动方向！
import android.view.MotionEvent;
import android.view.View;
public class SwipeDirectionListener implements View.OnTouchListener {
float deltaX ;
float deltaY ;
float maxValX;
float maxValY;
float firstTouchX;
float firstTouchY;
float currentX ;
float currentY ;
float SWIPE_THRESHOLD = 10.0f;
@Override
public boolean onTouch(View v, MotionEvent event) {
boolean result ;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//Register the first touch on TouchDown and this should not change unless finger goes up.
firstTouchX = event.getX();
firstTouchY = event.getY();
maxValX = 0.0f;
maxValY = 0.0f;
//As the event is consumed, return true
result = true;
break;
case MotionEvent.ACTION_MOVE:
//CurrentX/Y are the continues changing values of one single touch session. Change
//when finger slides on view
currentX = event.getX();
currentY = event.getY();
//setting the maximum value of X or Y so far. Any deviation in this means a change of direction so reset the firstTouch value to last known max value i.e MaxVal X/Y.
if(maxValX <currentX){
maxValX = currentX;
}else{
firstTouchX= maxValX;
maxValX =0.0f;
}
if(maxValY <currentY){
maxValY = currentY;
}else{
firstTouchY= maxValY;
maxValY =0.0f;
}
//DeltaX/Y are the difference between current touch and the value when finger first touched screen.
//If its negative that means current value is on left side of first touchdown value i.e Going left and
//vice versa.
deltaX = currentX - firstTouchX;
deltaY = currentY - firstTouchY;
if (Math.abs(deltaX) > Math.abs(deltaY)) {
//Horizontal swipe
if (Math.abs(deltaX) > SWIPE_THRESHOLD) {
if (deltaX > 0) {
//means we are going right
onRightSwipe(currentX);
} else {
//means we are going left
onLeftSwipe(currentX);
}
}
} else {
//It's a vertical swipe
if (Math.abs(deltaY) > SWIPE_THRESHOLD) {
if (deltaY > 0) {
//means we are going down
onDownSwipe(currentY);
} else {
//means we are going up
onUpSwipe(currentY);
}
}
}
result = true;
break;
case MotionEvent.ACTION_UP:
//Clean UP
firstTouchX = 0.0f;
firstTouchY = 0.0f;
result = true;
break;
default:
result = false;
break;
}
return result;
}
public void onUpSwipe(float value) {
}
public void onDownSwipe(float value) {
}
public void onRightSwipe(float value) {
}
public void onLeftSwipe(float value) {
}
}
这就像一个魅力！
实施：
yourView.setOnTouchListener(new SwipeDirectionListener() {
public void onUpSwipe(float value) {
mTextView.setText("onUpSwipe :"+value);
}
public void onDownSwipe(float value) {
mTextView.setText("onDownSwipe :"+value);
}
public void onRightSwipe(float value) {
mTextView.setText("onRightSwipe :"+value);
}
public void onLeftSwipe(float value) {
mTextView.setText("onLeftSwipe :"+value);
}
});
【讨论】：