AbstractSlideInView.java

/*
 * Copyright (C) 2017 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.views;

import static com.android.launcher3.anim.Interpolators.scrollInterpolatorForVelocity;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.animation.PropertyValuesHolder;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Property;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.Interpolator;

import com.android.launcher3.AbstractFloatingView;
import com.android.launcher3.Launcher;
import com.android.launcher3.LauncherAnimUtils;
import com.android.launcher3.Utilities;
import com.android.launcher3.anim.Interpolators;
import com.android.launcher3.touch.SwipeDetector;

/**
 * Extension of AbstractFloatingView with common methods for sliding in from bottom
 */
public abstract class AbstractSlideInView extends AbstractFloatingView
        implements SwipeDetector.Listener {

    protected static Property<AbstractSlideInView, Float> TRANSLATION_SHIFT =
            new Property<AbstractSlideInView, Float>(Float.class, "translationShift") {

                @Override
                public Float get(AbstractSlideInView view) {
                    return view.mTranslationShift;
                }

                @Override
                public void set(AbstractSlideInView view, Float value) {
                    view.setTranslationShift(value);
                }
            };
    protected static final float TRANSLATION_SHIFT_CLOSED = 1f;
    protected static final float TRANSLATION_SHIFT_OPENED = 0f;

    protected final Launcher mLauncher;
    protected final SwipeDetector mSwipeDetector;
    protected final ObjectAnimator mOpenCloseAnimator;

    protected View mContent;
    protected Interpolator mScrollInterpolator;

    // range [0, 1], 0=> completely open, 1=> completely closed
    protected float mTranslationShift = TRANSLATION_SHIFT_CLOSED;

    protected boolean mNoIntercept;

    public AbstractSlideInView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mLauncher = Launcher.getLauncher(context);

        mScrollInterpolator = Interpolators.SCROLL_CUBIC;
        mSwipeDetector = new SwipeDetector(context, this, SwipeDetector.VERTICAL);

        mOpenCloseAnimator = LauncherAnimUtils.ofPropertyValuesHolder(this);
        mOpenCloseAnimator.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                mSwipeDetector.finishedScrolling();
                announceAccessibilityChanges();
            }
        });
    }

    protected void setTranslationShift(float translationShift) {
        mTranslationShift = translationShift;
        mContent.setTranslationY(mTranslationShift * mContent.getHeight());
    }

    @Override
    public boolean onControllerInterceptTouchEvent(MotionEvent ev) {
        if (mNoIntercept) {
            return false;
        }

        int directionsToDetectScroll = mSwipeDetector.isIdleState() ?
                SwipeDetector.DIRECTION_NEGATIVE : 0;
        mSwipeDetector.setDetectableScrollConditions(
                directionsToDetectScroll, false);
        mSwipeDetector.onTouchEvent(ev);
        return mSwipeDetector.isDraggingOrSettling()
                || !mLauncher.getDragLayer().isEventOverView(mContent, ev);
    }

    @Override
    public boolean onControllerTouchEvent(MotionEvent ev) {
        mSwipeDetector.onTouchEvent(ev);
        if (ev.getAction() == MotionEvent.ACTION_UP && mSwipeDetector.isIdleState()) {
            // If we got ACTION_UP without ever starting swipe, close the panel.
            if (!mLauncher.getDragLayer().isEventOverView(mContent, ev)) {
                close(true);
            }
        }
        return true;
    }

    /* SwipeDetector.Listener */

    @Override
    public void onDragStart(boolean start) { }

    @Override
    public boolean onDrag(float displacement, float velocity) {
        float range = mContent.getHeight();
        displacement = Utilities.boundToRange(displacement, 0, range);
        setTranslationShift(displacement / range);
        return true;
    }

    @Override
    public void onDragEnd(float velocity, boolean fling) {
        if ((fling && velocity > 0) || mTranslationShift > 0.5f) {
            mScrollInterpolator = scrollInterpolatorForVelocity(velocity);
            mOpenCloseAnimator.setDuration(SwipeDetector.calculateDuration(
                    velocity, TRANSLATION_SHIFT_CLOSED - mTranslationShift));
            close(true);
        } else {
            mOpenCloseAnimator.setValues(PropertyValuesHolder.ofFloat(
                    TRANSLATION_SHIFT, TRANSLATION_SHIFT_OPENED));
            mOpenCloseAnimator.setDuration(
                    SwipeDetector.calculateDuration(velocity, mTranslationShift))
                    .setInterpolator(Interpolators.DEACCEL);
            mOpenCloseAnimator.start();
        }
    }

    protected void handleClose(boolean animate, long defaultDuration) {
        if (mIsOpen && !animate) {
            mOpenCloseAnimator.cancel();
            setTranslationShift(TRANSLATION_SHIFT_CLOSED);
            onCloseComplete();
            return;
        }
        if (!mIsOpen || mOpenCloseAnimator.isRunning()) {
            return;
        }
        mOpenCloseAnimator.setValues(
                PropertyValuesHolder.ofFloat(TRANSLATION_SHIFT, TRANSLATION_SHIFT_CLOSED));
        mOpenCloseAnimator.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                onCloseComplete();
            }
        });
        if (mSwipeDetector.isIdleState()) {
            mOpenCloseAnimator
                    .setDuration(defaultDuration)
                    .setInterpolator(Interpolators.ACCEL);
        } else {
            mOpenCloseAnimator.setInterpolator(mScrollInterpolator);
        }
        mOpenCloseAnimator.start();
    }

    protected void onCloseComplete() {
        mIsOpen = false;
        mLauncher.getDragLayer().removeView(this);
    }
}