package com.navigation.androidx;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;
import androidx.annotation.NonNull;
import androidx.core.view.ViewCompat;
import androidx.customview.widget.ViewDragHelper;
/**
* Created by Listen on 2018/7/1.
* <p>
* modified from https://github.com/ikew0ng/SwipeBackLayout
*/
public class SwipeBackLayout extends FrameLayout {
private static String TAG = "SwipeBackLayout";
/**
* Minimum velocity that will be detected as a fling
*/
private static final int MIN_FLING_VELOCITY = 400; // dips per second
private static final int DEFAULT_SCRIM_COLOR = 0x10000000;
private static final int FULL_ALPHA = 255;
/**
* A view is not currently being dragged or animating as a result of a
* fling/snap.
*/
public static final int STATE_IDLE = ViewDragHelper.STATE_IDLE;
/**
* A view is currently being dragged. The position is currently changing as
* a result of user input or simulated user input.
*/
public static final int STATE_DRAGGING = ViewDragHelper.STATE_DRAGGING;
/**
* A view is currently settling into place as a result of a fling or
* predefined non-interactive motion.
*/
public static final int STATE_SETTLING = ViewDragHelper.STATE_SETTLING;
/**
* Default threshold of scroll
*/
private static final float DEFAULT_SCROLL_THRESHOLD = 0.5f;
private static final float DEFAULT_PARALLAX = 0.25f;
/**
* Threshold of scroll, we will close the activity, when scrollPercent over
* this value;
*/
private float mScrollThreshold = DEFAULT_SCROLL_THRESHOLD;
private float mParallaxOffset = DEFAULT_PARALLAX;
private View mCapturedView;
private ViewDragHelper mDragHelper;
private float mScrollPercent;
private int mLeft;
/**
* The set of listeners to be sent events through.
*/
private SwipeListener mListener;
private Drawable mTabBar;
private Rect mTabBarOriginBounds;
private float mScrimOpacity;
private int mScrimColor = DEFAULT_SCRIM_COLOR;
private boolean mInLayout;
public SwipeBackLayout(Context context) {
this(context, null);
}
public SwipeBackLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public SwipeBackLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs);
mDragHelper = ViewDragHelper.create(this, new ViewDragCallback());
final float density = getResources().getDisplayMetrics().density;
final float minVelocity = MIN_FLING_VELOCITY * density;
mDragHelper.setMinVelocity(minVelocity);
mDragHelper.setEdgeTrackingEnabled(ViewDragHelper.EDGE_LEFT);
}
public void setTabBar(Drawable drawable) {
this.mTabBar = drawable;
if (drawable != null) {
mTabBarOriginBounds = drawable.copyBounds();
}
}
public void setParallaxOffset(float offset) {
mParallaxOffset = offset;
}
/**
* Add a callback to be invoked when a swipe event is sent to this view.
*
* @param listener the swipe listener to attach to this view
*/
public void setSwipeListener(SwipeListener listener) {
mListener = listener;
}
public interface SwipeListener {
void onViewDragStateChanged(int state, float scrollPercent);
boolean shouldSwipeBack();
}
public void setScrollThresHold(float threshold) {
if (threshold >= 1.0f || threshold <= 0) {
throw new IllegalArgumentException("Threshold value should be between 0 and 1.0");
}
mScrollThreshold = threshold;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
if (!mListener.shouldSwipeBack()) {
return super.onInterceptTouchEvent(event);
}
try {
return mDragHelper.shouldInterceptTouchEvent(event);
} catch (ArrayIndexOutOfBoundsException e) {
return false;
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (!mListener.shouldSwipeBack()) {
return super.onTouchEvent(event);
}
mDragHelper.processTouchEvent(event);
return mDragHelper.getViewDragState() != ViewDragHelper.STATE_IDLE;
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
mInLayout = true;
if (mCapturedView != null)
mCapturedView.layout(mLeft, 0,
mLeft + mCapturedView.getMeasuredWidth(),
mCapturedView.getMeasuredHeight());
mInLayout = false;
}
@Override
public void requestLayout() {
if (!mInLayout) {
super.requestLayout();
}
}
@Override
protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
final boolean drawContent = child == mCapturedView;
int index = indexOfChild(child);
if (mDragHelper.getViewDragState() != ViewDragHelper.STATE_IDLE && index == getChildCount() - 2) {
View lastChild = getChildAt(getChildCount() - 1);
canvas.save();
canvas.clipRect(0, 0, lastChild.getLeft(), getHeight());
}
boolean ret = super.drawChild(canvas, child, drawingTime);
if (mDragHelper.getViewDragState() != ViewDragHelper.STATE_IDLE && index == getChildCount() - 2) {
canvas.restore();
}
if (mTabBar != null && drawContent) {
drawTabBar(canvas, child);
}
if (mScrimOpacity > 0 && drawContent
&& mDragHelper.getViewDragState() != ViewDragHelper.STATE_IDLE) {
drawScrim(canvas, child);
}
return ret;
}
private void drawScrim(Canvas canvas, View child) {
final int baseAlpha = (mScrimColor & 0xff000000) >>> 24;
final int alpha = (int) (baseAlpha * mScrimOpacity);
final int color = alpha << 24 | (mScrimColor & 0xffffff);
canvas.clipRect(0, 0, child.getLeft(), getHeight());
canvas.drawColor(color);
}
private void drawTabBar(Canvas canvas, View child) {
canvas.save();
canvas.clipRect(0, 0, child.getLeft(), getHeight());
int leftOffset = (int) ((mCapturedView.getLeft() - getWidth()) * mParallaxOffset * mScrimOpacity);
mTabBar.setBounds(leftOffset, mTabBarOriginBounds.top, mTabBarOriginBounds.right + leftOffset, mTabBarOriginBounds.bottom);
mTabBar.draw(canvas);
canvas.restore();
}
@Override
public void computeScroll() {
mScrimOpacity = 1 - mScrollPercent;
if (mDragHelper.continueSettling(true)) {
ViewCompat.postInvalidateOnAnimation(this);
}
int count = getChildCount();
if (mScrimOpacity >= 0 && mCapturedView != null && count > 1) {
int leftOffset = (int) ((mCapturedView.getLeft() - getWidth()) * mParallaxOffset * mScrimOpacity);
View underlying = getChildAt(count - 2);
underlying.setX(leftOffset > 0 ? 0 : leftOffset);
}
}
private class ViewDragCallback extends ViewDragHelper.Callback {
@Override
public boolean tryCaptureView(@NonNull View view, int pointerId) {
if (view.getAnimation() != null) {
return false;
}
boolean ret = mDragHelper.isEdgeTouched(ViewDragHelper.EDGE_LEFT, pointerId);
boolean directionCheck = !mDragHelper.checkTouchSlop(ViewDragHelper.DIRECTION_VERTICAL, pointerId);
return mDragHelper.getViewDragState() != ViewDragHelper.STATE_SETTLING && (ret & directionCheck);
}
@Override
public void onViewCaptured(@NonNull View capturedChild, int activePointerId) {
mCapturedView = capturedChild;
}
@Override
public int getViewHorizontalDragRange(@NonNull View child) {
return child.getWidth();
}
@Override
public void onViewPositionChanged(@NonNull View changedView, int left, int top, int dx, int dy) {
mScrollPercent = Math.abs((float) left / mCapturedView.getWidth());
mLeft = left;
invalidate();
}
@Override
public void onViewReleased(@NonNull View releasedChild, float xvel, float yvel) {
final int childWidth = releasedChild.getWidth();
int left = xvel > 0 || (xvel == 0 && mScrollPercent > mScrollThreshold) ? childWidth : 0;
mDragHelper.settleCapturedViewAt(left, 0);
invalidate();
}
@Override
public int clampViewPositionHorizontal(@NonNull View child, int left, int dx) {
return Math.min(child.getWidth(), Math.max(left, 0));
}
@Override
public void onViewDragStateChanged(int state) {
if (state == ViewDragHelper.STATE_IDLE) {
mCapturedView = null;
mLeft = 0;
int count = getChildCount();
if (count > 1) {
View underlying = getChildAt(count - 2);
underlying.setX(0);
}
}
mListener.onViewDragStateChanged(state, mScrollPercent);
}
}
}
