如何检测上的WebView滑动手势 [英] How to detect a swipe gesture on webview
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问题描述
我正在开发一个简单的Android应用程序与RelativeLayout的和一个web视图中。
i'm developing a simple android application with a RelativeLayout and a WebView inside.
我不得不从底部检测刷卡顶部的屏幕的左侧部分的20％，仅完成。因此，当从底部空间用户刷卡顶部我必须表现出一个自定义对话框。
I have to detect swipe from bottom to top done only in the 20% of the left part of the screen. So when user swipe in that space from bottom to top i have to show a custom dialog.
我做的尝试是：
import android.app.Activity;
import android.view.MotionEvent;
import android.view.View;
public class ActivitySwipeDetector implements View.OnTouchListener {
static final String logTag = "ActivitySwipeDetector";
private Activity activity;
static final int MIN_DISTANCE = 100;
private float downY, upY;
public ActivitySwipeDetector(Activity activity){
this.activity = activity;
}
public void onRightToLeftSwipe(){
}
public void onLeftToRightSwipe(){
}
public void onTopToBottomSwipe(){
}
public void onBottomToTopSwipe(){
System.out.println("BOTTOM TO TOP SWIPE DONE!");
}
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN: {
downY = event.getY();
return true;
}
case MotionEvent.ACTION_UP: {
upY = event.getY();
float deltaY = downY - upY;
if(Math.abs(deltaY) > MIN_DISTANCE){
if(deltaY > 0) { this.onBottomToTopSwipe(); return true; }
}
else {
return false;
}
return true;
}
}
return false;
}
}
layout = (RelativeLayout)this.findViewById(R.id.layout);
layout.setOnTouchListener(activitySwipeDetector);
不过，这并不什么都不做！
But it doesn't do nothing!
所以我尽量创造这样一个自定义的WebView：
So i try creating a custom webview in this way:
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.webkit.WebView;
public class MyWebView extends WebView {
public MyWebView(Context context) {
super(context);
}
public MyWebView(Context context,AttributeSet set){
super(context,set);
}
@Override
public boolean onTouchEvent(MotionEvent evt) {
boolean consumed = super.onTouchEvent(evt);
if (isClickable()) {
switch (evt.getAction()) {
case MotionEvent.ACTION_DOWN:
lastTouchY = evt.getY();
downTime = evt.getEventTime();
hasMoved = false;
break;
case MotionEvent.ACTION_MOVE:
hasMoved = moved(evt);
break;
case MotionEvent.ACTION_UP:
float actualTouchY = evt.getY();
long currentTime = evt.getEventTime();
float difference = Math.abs(lastTouchY - actualTouchY);
long time = currentTime - downTime;
if ( (lastTouchY < actualTouchY) && (time < 220) && (difference > 100) ) {
System.out.println("SWIPE1");
}
if ( (lastTouchY > actualTouchY) && (time < 220) && (difference > 100) ) {
System.out.println("SWIPE2");
}
break;
}
}
return consumed || isClickable();
}
long downTime;
private float lastTouchY;
private boolean hasMoved = false;
private boolean moved(MotionEvent evt) {
return hasMoved ||
Math.abs(evt.getY() - lastTouchY) > 10.0;
}
}
但没有成功！有人可以帮我吗？谢谢！！！！！ ：）
but with no success!!! can someone help me?? THAnks!!!!! :)
推荐答案
使用 GestureDetector 使用自定义Web视图。
Use a GestureDetector with a custom web view..
webView.setGestureDetector(new GestureDetector(new CustomeGestureDetector()));
手势检测：
private class CustomeGestureDetector extends SimpleOnGestureListener {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if(e1 == null || e2 == null) return false;
if(e1.getPointerCount() > 1 || e2.getPointerCount() > 1) return false;
else {
try { // right to left swipe .. go to next page
if(e1.getX() - e2.getX() > 100 && Math.abs(velocityX) > 800) {
//do your stuff
return true;
} //left to right swipe .. go to prev page
else if (e2.getX() - e1.getX() > 100 && Math.abs(velocityX) > 800) {
//do your stuff
return true;
} //bottom to top, go to next document
else if(e1.getY() - e2.getY() > 100 && Math.abs(velocityY) > 800
&& webView.getScrollY() >= webView.getScale() * (webView.getContentHeight() - webView.getHeight())) {
//do your stuff
return true;
} //top to bottom, go to prev document
else if (e2.getY() - e1.getY() > 100 && Math.abs(velocityY) > 800 ) {
//do your stuff
return true;
}
} catch (Exception e) { // nothing
}
return false;
}
}
}
自定义Web视图：
public final class CustomWebView extends WebView {
private GestureDetector gestureDetector;
/**
* @param context
* @param attrs
* @param defStyle
*/
public CustomWebView(Context context) {
super(context);
}
/**
* @param context
* @param attrs
* @param defStyle
*/
public CustomWebView(Context context, AttributeSet attrs) {
super(context, attrs);
}
/**
* @param context
* @param attrs
* @param defStyle
*/
public CustomWebView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
/*
* @see android.webkit.WebView#onScrollChanged(int, int, int, int)
*/
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
}
/*
* @see android.webkit.WebView#onTouchEvent(android.view.MotionEvent)
*/
@Override
public boolean onTouchEvent(MotionEvent ev) {
return gestureDetector.onTouchEvent(ev) || super.onTouchEvent(ev);
}
public void setGestureDetector(GestureDetector gestureDetector) {
this.gestureDetector = gestureDetector;
}
}
正如所说由АндрейМосквичёв：
As said by Андрей Москвичёв:
可以毫不派生的WebView类来解决，通过注册触摸监听器： webview.setOnTouchListener（新OnTouchListener（）...）并调用 gestureDetector.onTouchEvent（EV）从它。
It can be solved without deriving WebView class, by registering touch listener: webview.setOnTouchListener(new OnTouchListener() ...) and calling gestureDetector.onTouchEvent(ev) from it.
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