Move HideNonSystemOverlayMixin to SettingsLib

/*

 * Copyright (C) 2021 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.settingslib.core.lifecycle;

import static android.view.WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;

import static androidx.lifecycle.Lifecycle.Event.ON_START;

import static androidx.lifecycle.Lifecycle.Event.ON_STOP;

import android.app.Activity;

import android.provider.Settings;

import android.view.Window;

import android.view.WindowManager;

import androidx.annotation.VisibleForTesting;

import androidx.lifecycle.LifecycleObserver;

import androidx.lifecycle.OnLifecycleEvent;

/**

 * A mixin that adds window flag to prevent non-system overlays showing on top of Settings

 * activities.

 */

public class HideNonSystemOverlayMixin implements LifecycleObserver {

    public static final String SECURE_OVERLAY_SETTINGS = "secure_overlay_settings";

    private final Activity mActivity;

    public HideNonSystemOverlayMixin(Activity activity) {

        mActivity = activity;

    }

    @VisibleForTesting

    boolean isEnabled() {

        return Settings.Secure.getInt(mActivity.getContentResolver(),

                SECURE_OVERLAY_SETTINGS, 0 /* defValue */) == 0;

    }

    /**

     * Start Lifecycle event

     */

    @OnLifecycleEvent(ON_START)

    public void onStart() {

        if (mActivity == null || !isEnabled()) {

            return;

        }

        mActivity.getWindow().addSystemFlags(SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);

        android.util.EventLog.writeEvent(0x534e4554, "120484087", -1, "");

    }

    /**

     * Stop Lifecycle event

     */

    @OnLifecycleEvent(ON_STOP)

    public void onStop() {

        if (mActivity == null || !isEnabled()) {

            return;

        }

        final Window window = mActivity.getWindow();

        final WindowManager.LayoutParams attrs = window.getAttributes();

        attrs.privateFlags &= ~SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;

        window.setAttributes(attrs);

    }

}

/*

 * Copyright (C) 2021 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.settingslib.core.lifecycle;

import static android.view.WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;

import static com.android.settingslib.core.lifecycle.HideNonSystemOverlayMixin.SECURE_OVERLAY_SETTINGS;

import static com.google.common.truth.Truth.assertThat;

import android.os.Bundle;

import android.provider.Settings;

import android.view.WindowManager;

import androidx.annotation.Nullable;

import androidx.appcompat.app.AppCompatActivity;

import com.android.settingslib.R;

import org.junit.Before;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.robolectric.Robolectric;

import org.robolectric.RobolectricTestRunner;

import org.robolectric.android.controller.ActivityController;

@RunWith(RobolectricTestRunner.class)

public class HideNonSystemOverlayMixinTest {

    private ActivityController<TestActivity> mActivityController;

    @Before

    public void setUp() {

        mActivityController = Robolectric.buildActivity(TestActivity.class);

    }

    @Test

    public void startActivity_shouldHideNonSystemOverlay() {

        mActivityController.setup();

        TestActivity activity = mActivityController.get();

        // Activity start: HIDE_NON_SYSTEM_OVERLAY should be set.

        final WindowManager.LayoutParams attrs = activity.getWindow().getAttributes();

        assertThat(attrs.privateFlags & SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS)

                .isNotEqualTo(0);

    }

    @Test

    public void stopActivity_shouldUnhideNonSystemOverlay() {

        mActivityController.setup().stop();

        TestActivity activity = mActivityController.get();

        final WindowManager.LayoutParams attrs = activity.getWindow().getAttributes();

        assertThat(attrs.privateFlags & SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS)

                .isEqualTo(0);

    }

    @Test

    public void isEnabled_isAllowedOverlaySettings_returnFalse() {

        mActivityController.setup();

        final TestActivity activity = mActivityController.get();

        Settings.Secure.putInt(activity.getContentResolver(),

                SECURE_OVERLAY_SETTINGS, 1);

        assertThat(new HideNonSystemOverlayMixin(activity).isEnabled()).isFalse();

    }

    @Test

    public void isEnabled_isNotAllowedOverlaySettings_returnTrue() {

        mActivityController.setup();

        TestActivity activity = mActivityController.get();

        Settings.Secure.putInt(activity.getContentResolver(),

                SECURE_OVERLAY_SETTINGS, 0);

        assertThat(new HideNonSystemOverlayMixin(activity).isEnabled()).isTrue();

    }

    public static class TestActivity extends AppCompatActivity {

        @Override

        protected void onCreate(@Nullable Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);

            setTheme(R.style.Theme_AppCompat);

            getLifecycle().addObserver(new HideNonSystemOverlayMixin(this));

        }

    }

}