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/*
* 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 android.window;
import android.annotation.NonNull;
import android.app.Activity;
import android.app.Dialog;
import android.view.Window;
/**
* Callback allowing applications to handle back events in place of the system.
* <p>
* Callback instances can be added to and removed from {@link OnBackInvokedDispatcher}, which
* is held at window level and accessible through {@link Activity#getOnBackInvokedDispatcher()},
* {@link Dialog#getOnBackInvokedDispatcher()} and {@link Window#getOnBackInvokedDispatcher()}.
* <p>
* When back is triggered, callbacks on the in-focus window are invoked in reverse order in which
* they are added within the same priority. Between different priorities, callbacks with higher
* priority are invoked first.
* <p>
* This replaces {@link Activity#onBackPressed()}, {@link Dialog#onBackPressed()} and
* {@link android.view.KeyEvent#KEYCODE_BACK}
* <p>
* @see OnBackInvokedDispatcher#registerOnBackInvokedCallback(int, OnBackInvokedCallback)
* registerOnBackInvokedCallback(priority, OnBackInvokedCallback)
* to specify callback priority.
*/
@SuppressWarnings("deprecation")
public interface OnBackInvokedCallback {
/**
* Called when a back gesture has been started, or back button has been pressed down.
*
* @param backEvent The {@link BackEvent} containing information about the touch or
* button press.
*
* @hide
*/
default void onBackStarted(@NonNull BackEvent backEvent) {}
/**
* Called when a back gesture has been progressed.
*
* @param backEvent The {@link BackEvent} containing information about the latest touch point
* and the progress that the back animation should seek to.
*
* @hide
*/
default void onBackProgressed(@NonNull BackEvent backEvent) {}
/**
* Called when a back gesture has been completed and committed, or back button pressed
* has been released and committed.
*/
void onBackInvoked();
/**
* Called when a back gesture or button press has been cancelled.
*
* @hide
*/
default void onBackCancelled() {}
}
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