/*
* The MIT License (MIT)
*
* Copyright (c) 2015 XiNGRZ <xxx@oxo.ooo>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package org.softeg.slartus.forpdaplus.controls.imageview;
import android.content.Context;
import android.support.annotation.IntDef;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.FrameLayout;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
public class PullBackLayout extends FrameLayout {
/**
* Flag indicated pulling up is allowed
*
* @see #setDirection(int)
*/
public static final int DIRECTION_UP = 1;
/**
* Flag indicated pulling down is allowed
*
* @see #setDirection(int)
*/
public static final int DIRECTION_DOWN = 1 << 1;
private final ViewDragHelper dragger;
private final int minimumFlingVelocity;
@Direction
private int direction = DIRECTION_UP | DIRECTION_DOWN;
@Nullable
private Callback callback;
public PullBackLayout(Context context) {
this(context, null);
}
public PullBackLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public PullBackLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
dragger = ViewDragHelper.create(this, 1f / 8f, new ViewDragCallback());
minimumFlingVelocity = ViewConfiguration.get(context).getScaledMinimumFlingVelocity();
}
/**
* @return Allowed pulling direction
*/
@Direction
public int getDirection() {
return direction;
}
/**
* Sets pulling directions allowed
*
* @param direction Directions allowed
* @see #DIRECTION_UP
* @see #DIRECTION_DOWN
*/
public void setDirection(@Direction int direction) {
this.direction = direction;
}
public void setCallback(@Nullable Callback callback) {
this.callback = callback;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
try {
return dragger.shouldInterceptTouchEvent(ev);
} catch (Exception e) {
return false;
}
}
@Override
public boolean onTouchEvent(@NonNull MotionEvent event) {
try {
dragger.processTouchEvent(event);
return true;
} catch (Exception e) {
return false;
}
}
@Override
public void computeScroll() {
if (dragger.continueSettling(true)) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
private void onPullStart() {
if (callback != null) {
callback.onPullStart();
}
}
private void onPull(@Direction int direction, float progress) {
if (callback != null) {
callback.onPull(direction, progress);
}
}
private void onPullCancel(@Direction int direction) {
if (callback != null) {
callback.onPullCancel(direction);
}
}
private void onPullComplete(@Direction int direction) {
if (callback != null) {
callback.onPullComplete(direction);
}
}
private void reset() {
dragger.settleCapturedViewAt(0, 0);
invalidate();
}
@Retention(RetentionPolicy.SOURCE)
@IntDef(value = {DIRECTION_UP, DIRECTION_DOWN}, flag = true)
public @interface Direction {
}
public interface Callback {
void onPullStart();
void onPull(@Direction int direction, float progress);
void onPullCancel(@Direction int direction);
void onPullComplete(@Direction int direction);
}
private class ViewDragCallback extends ViewDragHelper.Callback {
@Override
public boolean tryCaptureView(View child, int pointerId) {
return true;
}
@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
return 0;
}
@Override
public int clampViewPositionVertical(View child, int top, int dy) {
if ((direction & (DIRECTION_UP | DIRECTION_DOWN)) != 0) {
return top;
} else if ((direction & DIRECTION_UP) != 0) {
return Math.min(0, top);
} else if ((direction & DIRECTION_DOWN) != 0) {
return Math.max(0, top);
} else {
return 0;
}
}
@Override
public int getViewHorizontalDragRange(View child) {
return 0;
}
@Override
public int getViewVerticalDragRange(View child) {
if (direction == 0) {
return 0;
} else if ((direction & (DIRECTION_UP | DIRECTION_DOWN)) != 0) {
return getHeight() * 2;
} else {
return getHeight();
}
}
@Override
public void onViewCaptured(View capturedChild, int activePointerId) {
onPullStart();
}
@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
if (top > 0) {
onPull(DIRECTION_DOWN, (float) top / (float) getHeight());
} else if (top < 0) {
onPull(DIRECTION_UP, (float) -top / (float) getHeight());
}
}
@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
int top = releasedChild.getTop();
int slop = Math.abs(yvel) > minimumFlingVelocity ? getHeight() / 6 : getHeight() / 3;
if (top > 0) {
if (top > slop) {
onPullComplete(DIRECTION_DOWN);
} else {
onPullCancel(DIRECTION_DOWN);
reset();
}
} else if (top < 0) {
if (top < -slop) {
onPullComplete(DIRECTION_UP);
} else {
onPullCancel(DIRECTION_UP);
reset();
}
}
}
}
}