Introduce KeepActivitiesPreferenceController

- Create new KeepActivitiesPreferenceController
 - Create controller inside the DashboardFragment
 - Port logic from DevelopmentSettings into the controller

Bug: 34203528
Test: make RunSettingsRoboTests -j40
Change-Id: I9e15d285eee51164dd5c3a07c4f2069bf4d73383

src/com/android/settings/development/DevelopmentSettingsDashboardFragment.java

@@ -304,7 +304,7 @@ public class DevelopmentSettingsDashboardFragment extends RestrictedDashboardFra
         // disable usb audio routing
         // strict mode enabled
         // profile gpu rendering
-        // don't keep activities
+        controllers.add(new KeepActivitiesPreferenceController(context));
         // background process limit
         // background check
         // show all anrs

src/com/android/settings/development/KeepActivitiesPreferenceController.java

@@ -0,0 +1,96 @@
+/*
+ * 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.settings.development;
+
+import android.app.ActivityManager;
+import android.app.IActivityManager;
+import android.content.Context;
+import android.os.RemoteException;
+import android.provider.Settings;
+import android.support.annotation.VisibleForTesting;
+import android.support.v14.preference.SwitchPreference;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceScreen;
+
+public class KeepActivitiesPreferenceController extends DeveloperOptionsPreferenceController
+        implements Preference.OnPreferenceChangeListener {
+
+    private static final String IMMEDIATELY_DESTROY_ACTIVITIES_KEY =
+            "immediately_destroy_activities";
+
+    @VisibleForTesting
+    static final int SETTING_VALUE_OFF = 0;
+
+    private IActivityManager mActivityManager;
+    private SwitchPreference mPreference;
+
+    public KeepActivitiesPreferenceController(Context context) {
+        super(context);
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return IMMEDIATELY_DESTROY_ACTIVITIES_KEY;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+
+        mPreference = (SwitchPreference) screen.findPreference(getPreferenceKey());
+        mActivityManager = getActivityManager();
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final boolean isEnabled = (Boolean) newValue;
+        writeImmediatelyDestroyActivitiesOptions(isEnabled);
+        return true;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        final int mode = Settings.Global.getInt(mContext.getContentResolver(),
+                Settings.Global.ALWAYS_FINISH_ACTIVITIES, SETTING_VALUE_OFF);
+        mPreference.setChecked(mode != SETTING_VALUE_OFF);
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchEnabled() {
+        mPreference.setEnabled(true);
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchDisabled() {
+        writeImmediatelyDestroyActivitiesOptions(false);
+        mPreference.setEnabled(false);
+        mPreference.setChecked(false);
+    }
+
+    private void writeImmediatelyDestroyActivitiesOptions(boolean isEnabled) {
+        try {
+            mActivityManager.setAlwaysFinish(isEnabled);
+        } catch (RemoteException ex) {
+            // intentional no-op
+        }
+    }
+
+    @VisibleForTesting
+    IActivityManager getActivityManager() {
+        return ActivityManager.getService();
+    }
+}

tests/robotests/src/com/android/settings/development/KeepActivitiesPreferenceControllerTest.java

@@ -0,0 +1,120 @@
+/*
+ * 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.settings.development;
+
+import static com.android.settings.development.KeepActivitiesPreferenceController.SETTING_VALUE_OFF;
+
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.IActivityManager;
+import android.content.Context;
+import android.os.RemoteException;
+import android.provider.Settings;
+import android.support.v14.preference.SwitchPreference;
+import android.support.v7.preference.PreferenceScreen;
+
+import com.android.settings.TestConfig;
+import com.android.settings.testutils.SettingsRobolectricTestRunner;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+@RunWith(SettingsRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class KeepActivitiesPreferenceControllerTest {
+
+    private static final int SETTING_VALUE_ON = 1;
+
+    @Mock
+    private SwitchPreference mPreference;
+    @Mock
+    private PreferenceScreen mPreferenceScreen;
+    @Mock
+    private IActivityManager mActivityManager;
+
+    private Context mContext;
+    private KeepActivitiesPreferenceController mController;
+
+    @Before
+    public void setup() {
+        MockitoAnnotations.initMocks(this);
+        mContext = RuntimeEnvironment.application;
+        mController = spy(new KeepActivitiesPreferenceController(mContext));
+        doReturn(mActivityManager).when(mController).getActivityManager();
+        when(mPreferenceScreen.findPreference(mController.getPreferenceKey())).thenReturn(
+                mPreference);
+        mController.displayPreference(mPreferenceScreen);
+    }
+
+    @Test
+    public void onPreferenceChanged_settingEnabled_turnOnDestroyActivities()
+            throws RemoteException {
+        mController.onPreferenceChange(mPreference, true /* new value */);
+
+        verify(mActivityManager).setAlwaysFinish(true);
+    }
+
+    @Test
+    public void onPreferenceChanged_settingDisabled_turnOffDestroyActivities()
+            throws RemoteException {
+        mController.onPreferenceChange(mPreference, false /* new value */);
+
+        verify(mActivityManager).setAlwaysFinish(false);
+    }
+
+    @Test
+    public void updateState_settingEnabled_preferenceShouldBeChecked() {
+        Settings.System.putInt(mContext.getContentResolver(),
+                Settings.Global.ALWAYS_FINISH_ACTIVITIES, SETTING_VALUE_ON);
+        mController.updateState(mPreference);
+
+        verify(mPreference).setChecked(true);
+    }
+
+    @Test
+    public void updateState_settingDisabled_preferenceShouldNotBeChecked() {
+        Settings.System.putInt(mContext.getContentResolver(),
+                Settings.Global.ALWAYS_FINISH_ACTIVITIES, SETTING_VALUE_OFF);
+        mController.updateState(mPreference);
+
+        verify(mPreference).setChecked(false);
+    }
+
+    @Test
+    public void onDeveloperOptionsDisabled_shouldDisablePreference() throws RemoteException {
+        mController.onDeveloperOptionsSwitchDisabled();
+
+        verify(mActivityManager).setAlwaysFinish(false);
+        verify(mPreference).setEnabled(false);
+        verify(mPreference).setChecked(false);
+    }
+
+    @Test
+    public void onDeveloperOptionsEnabled_shouldEnablePreference() {
+        mController.onDeveloperOptionsSwitchEnabled();
+
+        verify(mPreference).setEnabled(true);
+    }
+}