2022-10-21 18:52:52 +00:00

97 lines
3.5 KiB
Java

/*
* Copyright (C) 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.android.material.sidesheet;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import com.google.android.material.sidesheet.Sheet.SheetEdge;
import com.google.android.material.sidesheet.Sheet.StableSheetState;
import com.google.android.material.sidesheet.SideSheetBehavior.StateSettlingTracker;
/**
* A delegate for {@link SideSheetBehavior} to handle logic specific to the sheet's edge position.
*/
abstract class SheetDelegate {
/**
* Returns the edge of the screen in which the sheet is positioned. Must be a {@link SheetEdge}
* value.
*/
@SheetEdge
abstract int getSheetEdge();
/**
* Determines whether the sheet is currently settling to a target {@link StableSheetState} using
* {@link StateSettlingTracker}.
*/
abstract boolean isSettling(View child, int state, boolean isReleasingView);
/** Returns the sheet's offset from the origin edge when hidden. */
abstract int getHiddenOffset();
/** Returns the sheet's offset from the origin edge when expanded. */
abstract int getExpandedOffset();
/**
* Calculates the target {@link StableSheetState} state of the sheet after it's released from a
* drag, using the x and y velocity of the drag to determine the state.
*
* @return the target state
*/
@StableSheetState
abstract int calculateTargetStateOnViewReleased(
@NonNull View releasedChild, float xVelocity, float yVelocity);
/**
* Sets the target sheet state from the {@link
* SideSheetBehavior#onNestedPreScroll(CoordinatorLayout, View, View, int, int, int[], int)}
* callback, based on scroll and position information provided by the method parameters.
*/
abstract <V extends View> void setTargetStateOnNestedPreScroll(
@NonNull CoordinatorLayout coordinatorLayout,
@NonNull V child,
@NonNull View target,
int dx,
int dy,
@NonNull int[] consumed,
int type);
@StableSheetState
abstract <V extends View> int calculateTargetStateOnStopNestedScroll(@NonNull V child);
/**
* Whether the sheet has reached the expanded offset at the end of a nested scroll, used to
* determine when to set the {@link SideSheetBehavior.SheetState} to {@link
* SideSheetBehavior.SheetState#STATE_EXPANDED}.
*/
abstract <V extends View> boolean hasReachedExpandedOffset(@NonNull V child);
/**
* Whether the sheet should hide, based on the position of child, velocity of the drag event, and
* {@link SideSheetBehavior#getHideThreshold()}.
*/
abstract boolean shouldHide(@NonNull View child, float velocity);
/**
* Returns the edge of the sheet that the sheet expands towards, calling the child parameter's
* edge depending on which edge of the screen the sheet is positioned. For a right based sheet,
* this would return {@code child.getLeft()}.
*/
abstract <V extends View> int getOutwardEdge(@NonNull V child);
}