android/view/WindowInsetsController.java

/*
 * Copyright (C) 2018 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 android.view;

import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.graphics.Insets;
import android.inputmethodservice.InputMethodService;
import android.os.CancellationSignal;
import android.view.InsetsState.InternalInsetsType;
import android.view.WindowInsets.Type;
import android.view.WindowInsets.Type.InsetsType;
import android.view.animation.Interpolator;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * Interface to control windows that generate insets.
 *
 * TODO(118118435): Needs more information and examples once the API is more baked.
 */
public interface WindowInsetsController {

    /**
     * Makes status bars become opaque with solid dark background and light foreground.
     * @hide
     */
    int APPEARANCE_OPAQUE_STATUS_BARS = 1;

    /**
     * Makes navigation bars become opaque with solid dark background and light foreground.
     * @hide
     */
    int APPEARANCE_OPAQUE_NAVIGATION_BARS = 1 << 1;

    /**
     * Makes items on system bars become less noticeable without changing the layout of the bars.
     * @hide
     */
    int APPEARANCE_LOW_PROFILE_BARS = 1 << 2;

    /**
     * Changes the foreground color for light status bars so that the items on the bar can be read
     * clearly.
     */
    int APPEARANCE_LIGHT_STATUS_BARS = 1 << 3;

    /**
     * Changes the foreground color for light navigation bars so that the items on the bar can be
     * read clearly.
     */
    int APPEARANCE_LIGHT_NAVIGATION_BARS = 1 << 4;

    /**
     * Determines the appearance of system bars.
     * @hide
     */
    @Retention(RetentionPolicy.SOURCE)
    @IntDef(flag = true, value = {APPEARANCE_OPAQUE_STATUS_BARS, APPEARANCE_OPAQUE_NAVIGATION_BARS,
            APPEARANCE_LOW_PROFILE_BARS, APPEARANCE_LIGHT_STATUS_BARS,
            APPEARANCE_LIGHT_NAVIGATION_BARS})
    @interface Appearance {
    }

    /**
     * The default option for {@link #setSystemBarsBehavior(int)}. System bars will be forcibly
     * shown on any user interaction on the corresponding display if navigation bars are hidden by
     * {@link #hide(int)} or
     * {@link WindowInsetsAnimationController#setInsetsAndAlpha(Insets, float, float)}.
     */
    int BEHAVIOR_SHOW_BARS_BY_TOUCH = 0;

    /**
     * Option for {@link #setSystemBarsBehavior(int)}: Window would like to remain interactive when
     * hiding navigation bars by calling {@link #hide(int)} or
     * {@link WindowInsetsAnimationController#setInsetsAndAlpha(Insets, float, float)}.
     *
     * <p>When system bars are hidden in this mode, they can be revealed with system gestures, such
     * as swiping from the edge of the screen where the bar is hidden from.</p>
     */
    int BEHAVIOR_SHOW_BARS_BY_SWIPE = 1;

    /**
     * Option for {@link #setSystemBarsBehavior(int)}: Window would like to remain interactive when
     * hiding navigation bars by calling {@link #hide(int)} or
     * {@link WindowInsetsAnimationController#setInsetsAndAlpha(Insets, float, float)}.
     *
     * <p>When system bars are hidden in this mode, they can be revealed temporarily with system
     * gestures, such as swiping from the edge of the screen where the bar is hidden from. These
     * transient system bars will overlay app’s content, may have some degree of transparency, and
     * will automatically hide after a short timeout.</p>
     */
    int BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE = 2;

    /**
     * Determines the behavior of system bars when hiding them by calling {@link #hide}.
     * @hide
     */
    @Retention(RetentionPolicy.SOURCE)
    @IntDef(value = {BEHAVIOR_SHOW_BARS_BY_TOUCH, BEHAVIOR_SHOW_BARS_BY_SWIPE,
            BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE})
    @interface Behavior {
    }

    /**
     * Makes a set of windows that cause insets appear on screen.
     * <p>
     * Note that if the window currently doesn't have control over a certain type, it will apply the
     * change as soon as the window gains control. The app can listen to the event by observing
     * {@link View#onApplyWindowInsets} and checking visibility with {@link WindowInsets#isVisible}.
     *
     * @param types A bitmask of {@link InsetsType} specifying what windows the app
     *              would like to make appear on screen.
     */
    void show(@InsetsType int types);

    /**
     * Makes a set of windows causing insets disappear.
     * <p>
     * Note that if the window currently doesn't have control over a certain type, it will apply the
     * change as soon as the window gains control. The app can listen to the event by observing
     * {@link View#onApplyWindowInsets} and checking visibility with {@link WindowInsets#isVisible}.
     *
     * @param types A bitmask of {@link InsetsType} specifying what windows the app
     *              would like to make disappear.
     */
    void hide(@InsetsType int types);

    /**
     * Lets the application control window inset animations in a frame-by-frame manner by modifying
     * the position of the windows in the system causing insets directly.
     *
     * @param types The {@link InsetsType}s the application has requested to control.
     * @param durationMillis Duration of animation in
     *                       {@link java.util.concurrent.TimeUnit#MILLISECONDS}, or -1 if the
     *                       animation doesn't have a predetermined duration. This value will be
     *                       passed to {@link WindowInsetsAnimation#getDurationMillis()}
     * @param interpolator The interpolator used for this animation, or {@code null} if this
     *                     animation doesn't follow an interpolation curve. This value will be
     *                     passed to {@link WindowInsetsAnimation#getInterpolator()} and used to
     *                     calculate {@link WindowInsetsAnimation#getInterpolatedFraction()}.
     * @param listener The {@link WindowInsetsAnimationControlListener} that gets called when the
     *                 windows are ready to be controlled, among other callbacks.
     * @param cancellationSignal A cancellation signal that the caller can use to cancel the
     *                           request to obtain control, or once they have control, to cancel the
     *                           control.
     * @see WindowInsetsAnimation#getFraction()
     * @see WindowInsetsAnimation#getInterpolatedFraction()
     * @see WindowInsetsAnimation#getInterpolator()
     * @see WindowInsetsAnimation#getDurationMillis()
     */
    void controlWindowInsetsAnimation(@InsetsType int types, long durationMillis,
            @Nullable Interpolator interpolator,
            @Nullable CancellationSignal cancellationSignal,
            @NonNull WindowInsetsAnimationControlListener listener);

    /**
     * Controls the appearance of system bars.
     * <p>
     * For example, the following statement adds {@link #APPEARANCE_LIGHT_STATUS_BARS}:
     * <pre>
     * setSystemBarsAppearance(APPEARANCE_LIGHT_STATUS_BARS, APPEARANCE_LIGHT_STATUS_BARS)
     * </pre>
     * And the following statement clears it:
     * <pre>
     * setSystemBarsAppearance(0, APPEARANCE_LIGHT_STATUS_BARS)
     * </pre>
     *
     * @param appearance Bitmask of {@link Appearance} flags.
     * @param mask Specifies which flags of appearance should be changed.
     * @see #getSystemBarsAppearance
     */
    void setSystemBarsAppearance(@Appearance int appearance, @Appearance int mask);

    /**
     * Retrieves the requested appearance of system bars.
     *
     * @return The requested bitmask of system bar appearance controlled by this window.
     * @see #setSystemBarsAppearance(int, int)
     */
    @Appearance int getSystemBarsAppearance();

    /**
     * Notify the caption insets height change. The information will be used on the client side to,
     * make sure the InsetsState has the correct caption insets.
     *
     * @param height the height of caption bar insets.
     * @hide
     */
    void setCaptionInsetsHeight(int height);

    /**
     * Controls the behavior of system bars.
     *
     * @param behavior Determines how the bars behave when being hidden by the application.
     * @see #getSystemBarsBehavior
     */
    void setSystemBarsBehavior(@Behavior int behavior);

    /**
     * Retrieves the requested behavior of system bars.
     *
     * @return the system bar behavior controlled by this window.
     * @see #setSystemBarsBehavior(int)
     */
    @Behavior int getSystemBarsBehavior();

    /**
     * @hide
     */
    InsetsState getState();

    /**
     * @return Whether the specified insets source is currently requested to be visible by the
     *         application.
     * @hide
     */
    boolean isRequestedVisible(@InternalInsetsType int type);

    /**
     * Adds a {@link OnControllableInsetsChangedListener} to the window insets controller.
     *
     * @param listener The listener to add.
     *
     * @see OnControllableInsetsChangedListener
     * @see #removeOnControllableInsetsChangedListener(OnControllableInsetsChangedListener)
     */
    void addOnControllableInsetsChangedListener(
            @NonNull OnControllableInsetsChangedListener listener);

    /**
     * Removes a {@link OnControllableInsetsChangedListener} from the window insets controller.
     *
     * @param listener The listener to remove.
     *
     * @see OnControllableInsetsChangedListener
     * @see #addOnControllableInsetsChangedListener(OnControllableInsetsChangedListener)
     */
    void removeOnControllableInsetsChangedListener(
            @NonNull OnControllableInsetsChangedListener listener);

    /**
     * Listener to be notified when the set of controllable {@link InsetsType} controlled by a
     * {@link WindowInsetsController} changes.
     * <p>
     * Once a {@link InsetsType} becomes controllable, the app will be able to control the window
     * that is causing this type of insets by calling {@link #controlWindowInsetsAnimation}.
     * <p>
     * Note: When listening to controllability of the {@link Type#ime},
     * {@link #controlWindowInsetsAnimation} may still fail in case the {@link InputMethodService}
     * decides to cancel the show request. This could happen when there is a hardware keyboard
     * attached.
     *
     * @see #addOnControllableInsetsChangedListener(OnControllableInsetsChangedListener)
     * @see #removeOnControllableInsetsChangedListener(OnControllableInsetsChangedListener)
     */
    interface OnControllableInsetsChangedListener {

        /**
         * Called when the set of controllable {@link InsetsType} changes.
         *
         * @param controller The controller for which the set of controllable {@link InsetsType}s
         *                   are changing.
         * @param typeMask Bitwise type-mask of the {@link InsetsType}s the controller is currently
         *                 able to control.
         */
        void onControllableInsetsChanged(@NonNull WindowInsetsController controller,
                @InsetsType int typeMask);
    }
}