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这是手势拦截类的源码。注释，也加的随地时，方便阅读理解。在源码后面，会有使用案例。
package com.laka.robotdog.widget;
import android.content.Context;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
/**
* @Author Lyf
* @CreateTime 2018/3/26
* @Description 手势拦截类。用于简化，拦截水平或垂直的手势。
**/
public class InterceptTouchListener implements View.OnTouchListener {
// 上下文，建议用全局上下文
// private Context mContext;
// 按压到屏幕时的坐标
private float[] mCoordinate;
// 最小的滑动距离，不同手机不同
private int mMinimumSlop;
// 两个回调接口，当触发水平或垂直手势时，会被调用
private OnHorizontalGestureListener mOnHorizontalGestureListener;
private OnVerticalGestureListener mOnVerticalGestureListener;
public InterceptTouchListener(Context mContext) {
mCoordinate = new float[2];
mMinimumSlop = ViewConfiguration.get(mContext).getScaledTouchSlop();
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// 保存按压到屏幕时的坐标
setCoordinate(event);
break;
case MotionEvent.ACTION_MOVE:
if (isClickEvent(event)) {
// 不处理点击事件，因为部分机型的点击事件会触发ACTION_MOVE，所以这里要做过滤。
break;
} else {
if (mOnHorizontalGestureListener != null
&& isHorizontalGestureEvent(event)) {
return mOnHorizontalGestureListener.onHorizontalGesture(event.getX(), mCoordinate[0]);
}
if (mOnVerticalGestureListener != null
&& isVerticalGestureEvent(event)) {
return mOnVerticalGestureListener.onVerticalGesture(event.getY(), mCoordinate[1]);
}
}
break;
case MotionEvent.ACTION_UP:
break;
}
return false;
}
/**
* @return return true 如果用户当前正在进行水平方向的手势操作
*/
private boolean isHorizontalGestureEvent(MotionEvent event) {
float slopX = getSlopX(event);
// 滑动距离，必须大于最小滑动距离。
return slopX > mMinimumSlop && slopX >= getSlopY(event);
}
/**
* @return return true 如果用户当前正在进行垂直方向的手势操作
*/
private boolean isVerticalGestureEvent(MotionEvent event) {
float slopY = getSlopY(event);
// 滑动距离，必须大于最小滑动距离。
return slopY > mMinimumSlop && getSlopX(event) < slopY;
}
/**
* @return return true 如果并没有移动，只是点击而已。
*/
private boolean isClickEvent(MotionEvent event) {
return getSlopX(event) == 0 && getSlopY(event) == 0;
}
/**
* 保存坐标
*/
private void setCoordinate(MotionEvent event) {
mCoordinate[0] = event.getX();
mCoordinate[1] = event.getY();
}
/**
* @return 水平滑动的距离
*/
private float getSlopX(MotionEvent event) {
return Math.abs(event.getX() - mCoordinate[0]);
}
/**
* @return 垂直滑动的距离
*/
private float getSlopY(MotionEvent event) {
return Math.abs(event.getY() - mCoordinate[1]);
}
public InterceptTouchListener setOnHorizontalGestureListener(OnHorizontalGestureListener mOnHorizontalGestureListener) {
this.mOnHorizontalGestureListener = mOnHorizontalGestureListener;
return this;
}
public InterceptTouchListener setOnVerticalGestureListener(OnVerticalGestureListener mOnVerticalGestureListener) {
this.mOnVerticalGestureListener = mOnVerticalGestureListener;
return this;
}
public interface OnHorizontalGestureListener {
/**
* 当用户在进行水平方向的操作时，该方法会被调用
*
* @param currentX 当前的X坐标
* @param lastX 上一次的X坐标
* @return return true 如果要拦截事件。
*/
boolean onHorizontalGesture(float currentX, float lastX);
}
public interface OnVerticalGestureListener {
/**
* 当用户在进行垂直方向的操作时，该方法会被调用
*
* @param currentY 当前的Y坐标
* @param lastY 上一次的Y坐标
* @return return true 如果要拦截事件。
*/
boolean onVerticalGesture(float currentY, float lastY);
}
}
使用案例
// 设置触摸事件，mDrawer可以是任意需要设置OnTouchListener的View.
mDrawer.setOnTouchListener(new InterceptTouchListener(this)
.setOnHorizontalGestureListener(new InterceptTouchListener
.OnHorizontalGestureListener() {
@Override
public boolean onHorizontalGesture(float currentX, float lastX) {
// 从左向右滑
if (currentX - lastX > 0) {
if (!mDrawer.isDrawerOpen(mDrawerContentView)) {
mDrawer.openDrawer(Gravity.START);
}
} else {
// 从右向左滑
if (mDrawer.isDrawerOpen(mDrawerContentView)) {
mDrawer.closeDrawer(Gravity.START);
}
}
return true;
}
}));
———————————————————————————————————Lambda语法版——————————————————————————————————————————————
// Lambda语法版
mDrawer.setOnTouchListener(new InterceptTouchListener(this)
.setOnHorizontalGestureListener((currX, lastX) -> {
// 从左向右滑
if (currX - lastX > 0) {
if (!mDrawer.isDrawerOpen(mDrawerContentView)) {
mDrawer.openDrawer(Gravity.START);
}
} else {
// 从右向左滑
if (mDrawer.isDrawerOpen(mDrawerContentView)) {
mDrawer.closeDrawer(Gravity.START);
}
}
return true;
}));从使用上，可以看出。这个类，简化了手势操作的判断。你可以把你的精力专注于：当水平或垂直事件，被触发时。你要做什么业务，以及需不需要拦截手势事件就行。下面是英文注释版本：
这是，英文注释版本：
package com.laka.robotdog.widget;
import android.content.Context;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
/**
* @Author Lyf
* @CreateTime 2018/3/26
* @Description An InterceptTouchListener is a class for intercepting Gestures.
* For Instance, moving finger from top to down or from left to right on Screen.
**/
public class InterceptTouchListener implements View.OnTouchListener {
// Context, It also can be an Application Context.
// private Context mContext;
// Coordinate of the point You pressed on Screen.
private float[] mCoordinate;
// Distance in pixels a touch can wander before we think the user is scrolling
private int mMinimumSlop;
// These interfaces definition for callback When the user vertically or horizontally moving his finger on the screen.
private OnHorizontalGestureListener mOnHorizontalGestureListener;
private OnVerticalGestureListener mOnVerticalGestureListener;
public InterceptTouchListener(Context mContext) {
mCoordinate = new float[2];
mMinimumSlop = ViewConfiguration.get(mContext).getScaledTouchSlop();
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// Save the coordinate of the point you were click on the screen.
setCoordinate(event);
break;
case MotionEvent.ACTION_MOVE:
if (isClickEvent(event)) {
// We don't deal with click Event in here.
break;
} else {
if (mOnHorizontalGestureListener != null
&& isHorizontalGestureEvent(event)) {
return mOnHorizontalGestureListener.onHorizontalGesture(event.getX(), mCoordinate[0]);
}
if (mOnVerticalGestureListener != null
&& isVerticalGestureEvent(event)) {
return mOnVerticalGestureListener.onVerticalGesture(event.getY(), mCoordinate[1]);
}
}
break;
case MotionEvent.ACTION_UP:
break;
}
return false;
}
/**
* Horizontal Gesture Event is an event, from left to right or a reverse action.
*
* @return return true if the user is moving his finger from left to right or from right to left.
*/
private boolean isHorizontalGestureEvent(MotionEvent event) {
float slopX = getSlopX(event);
return slopX > mMinimumSlop && slopX >= getSlopY(event);
}
/**
* Horizontal Gesture Event is an event, from top to down or a reverse action.
*
* @return return true if the user is moving his finger from top to down or from down to top.
*/
private boolean isVerticalGestureEvent(MotionEvent event) {
float slopY = getSlopY(event);
return slopY > mMinimumSlop && getSlopX(event) < slopY;
}
/**
* Some phones will perform the ACTION_MOVE action When the user just clicked the screen.
* This shouldn't be. Anyway, We gotta deal with it. So that I created this method.
*
* @return return true if the action is just a pressed action.
*/
private boolean isClickEvent(MotionEvent event) {
return getSlopX(event) == 0 && getSlopY(event) == 0;
}
private void setCoordinate(MotionEvent event) {
mCoordinate[0] = event.getX();
mCoordinate[1] = event.getY();
}
/**
* Distance in horizontal orientation of the user moving on.
*/
private float getSlopX(MotionEvent event) {
return Math.abs(event.getX() - mCoordinate[0]);
}
/**
* Distance in vertical orientation of the user moving on.
*/
private float getSlopY(MotionEvent event) {
return Math.abs(event.getY() - mCoordinate[1]);
}
public InterceptTouchListener setOnHorizontalGestureListener(OnHorizontalGestureListener mOnHorizontalGestureListener) {
this.mOnHorizontalGestureListener = mOnHorizontalGestureListener;
return this;
}
public InterceptTouchListener setOnVerticalGestureListener(OnVerticalGestureListener mOnVerticalGestureListener) {
this.mOnVerticalGestureListener = mOnVerticalGestureListener;
return this;
}
public interface OnHorizontalGestureListener {
/**
* Called When user is moving his finger in horizontally orientation.
*
* @return return true if you want to intercept the touch Event.
*/
boolean onHorizontalGesture(float currentX, float lastX);
}
/**
* Called When user is moving his finger in vertically orientation.
*
* @return return true if you want to intercept the touch Event.
*/
public interface OnVerticalGestureListener {
boolean onVerticalGesture(float currentY, float lastY);
}
}
Thank you for reading my posted. If you have any questions, You can comment below. Thank you.