src/com/android/launcher3/touch/AllAppsSwipeController.java

/**
 * Copyright (C) 2019 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.android.launcher3.touch;

import static com.android.launcher3.LauncherState.ALL_APPS;
import static com.android.launcher3.LauncherState.NORMAL;

import android.view.MotionEvent;

import com.android.launcher3.AbstractFloatingView;
import com.android.launcher3.Launcher;
import com.android.launcher3.LauncherState;

/**
 * TouchController to switch between NORMAL and ALL_APPS state.
 */
public class AllAppsSwipeController extends AbstractStateChangeTouchController {

    public AllAppsSwipeController(Launcher l) {
        super(l, SingleAxisSwipeDetector.VERTICAL);
    }

    @Override
    protected boolean canInterceptTouch(MotionEvent ev) {
        if (mCurrentAnimation != null) {
            // If we are already animating from a previous state, we can intercept.
            return true;
        }
        if (AbstractFloatingView.getTopOpenView(mLauncher) != null) {
            return false;
        }
        if (!mLauncher.isInState(NORMAL) && !mLauncher.isInState(ALL_APPS)) {
            // Don't listen for the swipe gesture if we are already in some other state.
            return false;
        }
        if (mLauncher.isInState(ALL_APPS) && !mLauncher.getAppsView().shouldContainerScroll(ev)) {
            return false;
        }
        return true;
    }

    @Override
    protected LauncherState getTargetState(LauncherState fromState, boolean isDragTowardPositive) {
        if (fromState == NORMAL && isDragTowardPositive) {
            return ALL_APPS;
        } else if (fromState == ALL_APPS && !isDragTowardPositive) {
            return NORMAL;
        }
        return fromState;
    }

    @Override
    protected float initCurrentAnimation() {
        float range = getShiftRange();
        long maxAccuracy = (long) (2 * range);
        mCurrentAnimation = mLauncher.getStateManager()
                .createAnimationToNewWorkspace(mToState, maxAccuracy);
        float startVerticalShift = mFromState.getVerticalProgress(mLauncher) * range;
        float endVerticalShift = mToState.getVerticalProgress(mLauncher) * range;
        float totalShift = endVerticalShift - startVerticalShift;
        return 1 / totalShift;
    }
}