【发布时间】：2016-11-19 08:15:56
【问题描述】：
我正在尝试构建一个组件，可以在其中向所有方向刷卡并可以将其带回。转换为以下内容：
- 从左到右：带回上一张卡片
- 从右到左：将新卡放在下面
- 从上到下：带回上一张卡片
- 从下到上：将新卡放在下面
我认为最好的前进方式是扩展 Viewpager 并将垂直和水平 Viewpager 实现结合起来。它将解决所有与动画相关的问题以及片段管理工作。
最终，我能够创建我想要的东西，但它现在卡在了最后一个问题上。当 Viewpager 垂直滑动时，它的标记区域表现流畅，但暗区无法正确滑动（下图）。对于垂直滑动实现，我使用了触摸坐标交换方法并映射了坐标。我试图查看映射以进行交换，但看不到我哪里出错了。
如果有人能指出我正确的方向，那将是一个很大的帮助：
以下是代码片段：
AllDirectionViewPager.java
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
public class AllDirectionViewPager extends ViewPager {
public static String TAG = "AllDirectionViewPager";
private float startX, startY, mHeight, mWidth;
int DIRECTION_LOCKING_THRESHOLD_X=5, DIRECTION_LOCKING_THRESHOLD_Y=5, mDirection=-1;
boolean directionLocked=false;
VDepthPageTransformer mVerticalTransformer;
HDepthPageTransformer mHorizontalTransformer;
public AllDirectionViewPager(Context context) {
super(context);
init();
}
public AllDirectionViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
setOverScrollMode(OVER_SCROLL_NEVER);
mVerticalTransformer = new VDepthPageTransformer();
mHorizontalTransformer = new HDepthPageTransformer();
}
/**
* Swaps the X and Y coordinates of touch event.
*/
private MotionEvent swapXY(MotionEvent ev) {
float width = getWidth();
float height = getHeight();
float newX = (ev.getY() / height) * width;
float newY = (ev.getX() / width) * height;
Log.i(TAG, "swap xy called. init: "+ev.getX()+","+ev.getY()+" final: "+newX+","+newY+" with height: "+height);
ev.setLocation(newX, newY);
return ev;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev){
boolean intercepted = false;
int direction;
direction = getDirection(ev);
Log.i(TAG, "viewpager intercepted: "+mDirection);
if(mDirection==0) {
intercepted = super.onInterceptTouchEvent(swapXY(ev));
swapXY(ev); // return touch coordinates to original reference frame for any child views
} else if (mDirection==1) {
intercepted = super.onInterceptTouchEvent(ev);
}
return intercepted;
}
//1: Left-Right; 0: UP-DOWN; -1: continuing
int getDirection(MotionEvent ev) {
float dirX=0, dirY=0;
boolean continuing = false;
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = ev.getX();
startY = ev.getY();
mDirection = -1;
directionLocked = false;
Log.d(TAG, "swipe start");
break;
case MotionEvent.ACTION_MOVE:
float endX = ev.getX();
float endY = ev.getY();
Log.d(TAG, "direction locked: "+directionLocked+" diffY: "+(endY - startY)+ " diffX: "+(endX - startX));
if (!directionLocked && ((Math.abs(endX - startX)>DIRECTION_LOCKING_THRESHOLD_X)||(Math.abs(endY - startY) > DIRECTION_LOCKING_THRESHOLD_Y))) {
dirX = (endX - startX) / getHeight();
dirY = (endY - startY) / getWidth();
directionLocked = true;
if (Math.abs(dirX) < Math.abs(dirY)) {
mDirection = 0;
this.setPageTransformer(true, mVerticalTransformer);
Log.d(TAG, "Vertical set");
}
else if (Math.abs(dirX) > Math.abs(dirY)) {
mDirection = 1;
this.setPageTransformer(true, mHorizontalTransformer);
Log.d(TAG, "Horizontal set");
}
else {
mDirection = -1;
directionLocked = false;
Log.d(TAG, "nothing found");
}
}
break;
case MotionEvent.ACTION_UP:
Log.d(TAG, "swipe done");
directionLocked = false;
break;
default:
continuing = true;
}
if(continuing)
return -1;
return -1;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
int direction = getDirection(ev);
Log.i(TAG, "viewpager touch: "+mDirection);
Log.i(TAG, "Touch coords: "+ev.getX()+","+ev.getY());
if(mDirection==0) {
return super.onTouchEvent(swapXY(ev));
}else/* if(mDirection==1) */{
return super.onTouchEvent(ev);
}
// return false;
}
}
HDepthPageTransformer.java
import android.support.v4.view.ViewPager;
import android.view.View;
public class HDepthPageTransformer implements ViewPager.PageTransformer {
private static final float MIN_SCALE = 0.85f;
public void transformPage(View view, float position) {
int pageWidth = view.getWidth();
if (position < -1) { // [-Infinity,-1)
// This page is way off-screen to the left.
view.setAlpha(0);
} else if (position <= 0) { // [-1,0]
// Use the default slide transition when moving to the left page
view.setAlpha(1);
view.setTranslationX(0);
view.setScaleX(1);
view.setScaleY(1);
} else if (position <= 1) { // (0,1]
// Fade the page out.
view.setAlpha(1);
// Counteract the default slide transition
view.setTranslationX(pageWidth * -position);
// Scale the page down (between MIN_SCALE and 1)
float scaleFactor = MIN_SCALE
+ (1 - MIN_SCALE) * (1 - Math.abs(position));
view.setScaleX(scaleFactor);
view.setScaleY(scaleFactor);
} else { // (1,+Infinity]
// This page is way off-screen to the right.
view.setAlpha(0);
}
}
}
VDepthPageTransformer.java
import android.support.v4.view.ViewPager;
import android.view.View;
public class VDepthPageTransformer implements ViewPager.PageTransformer {
private static final float MIN_SCALE = 0.85f;
public void transformPage(View view, float position) {
int pageWidth = view.getWidth();
if (position < -1) { // [-Infinity,-1)
// This page is way off-screen to the left.
view.setAlpha(0);
} else if (position <= 0) { // [-1,0]
// Use the default slide transition when moving to the top page
view.setAlpha(1);
// Counteract the default slide transition
view.setTranslationX(view.getWidth() * -position);
//set Y position to swipe in from top
float yPosition = position * view.getHeight();
view.setTranslationY(yPosition);
view.setScaleX(1);
view.setScaleY(1);
} else if (position <= 1) { // (0,1]
// Fade the page out.
view.setAlpha(1 - position);
// Counteract the default slide transition
view.setTranslationX(pageWidth * -position);
// Scale the page down (between MIN_SCALE and 1)
float scaleFactor = MIN_SCALE
+ (1 - MIN_SCALE) * (1 - Math.abs(position));
view.setScaleX(scaleFactor);
view.setScaleY(scaleFactor);
} else { // (1,+Infinity]
// This page is way off-screen to the right.
view.setAlpha(0);
}
}
}
深度页面转换器来自 android 开发者网站。 使用此处的某些部分进行垂直滚动：Android: Vertical ViewPager
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