Create an overlay to add a photo and video deletion helper service.

This overlay defines a checkbox preference in the deletion helper for
facilitating the deletion of photos and videos. The service which
provides deletion clearing can be overridden and used to create a
custom photo and video deletion helper.

Bug: 28554187
Bug: 28560856

Change-Id: Id5d9671a307aaac0d1331f055b8f2ab7aa67977c

src/com/android/settings/PhotosDeletionPreference.java

@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2016 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;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.graphics.drawable.Drawable;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.Preference.OnPreferenceChangeListener;
+import android.support.v7.preference.CheckBoxPreference;
+import android.support.v7.preference.PreferenceViewHolder;
+import android.util.AttributeSet;
+import android.util.TypedValue;
+import android.text.format.Formatter;
+import android.widget.TextView;
+import com.android.settings.deletionhelper.DeletionType;
+
+/**
+ * Preference to handle the deletion of photos and videos in the Deletion Helper.
+ */
+public class PhotosDeletionPreference extends CheckBoxPreference implements
+        DeletionType.FreeableChangedListener, OnPreferenceChangeListener {
+    // TODO(b/28560570): Remove this dummy value.
+    private static final int FAKE_DAYS_TO_KEEP = 30;
+    private DeletionType.FreeableChangedListener mListener;
+    private boolean mChecked;
+    private long mFreeableBytes;
+    private int mFreeableItems;
+    private DeletionType mDeletionService;
+
+    public PhotosDeletionPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        setIcon(getIcon(context));
+        updatePreferenceText();
+        setOnPreferenceChangeListener(this);
+    }
+
+    @Override
+    public void onBindViewHolder(PreferenceViewHolder holder) {
+        super.onBindViewHolder(holder);
+        final TextView titleView = (TextView) holder.findViewById(android.R.id.title);
+        if (titleView != null) {
+            titleView.setTextColor(getTintColor(getContext()));
+        }
+    }
+
+    /**
+     * Get the tint color for the preference's icon and text.
+     * @param context UI context to get the theme.
+     * @return The tint color.
+     */
+    public int getTintColor(Context context) {
+        TypedValue value = new TypedValue();
+        context.getTheme().resolveAttribute(android.R.attr.colorAccent, value, true);
+        return context.getColor(value.resourceId);
+    }
+
+    /**
+     * Updates the title and summary of the preference with fresh information.
+     */
+    public void updatePreferenceText() {
+        Context context = getContext();
+        setTitle(context.getString(R.string.deletion_helper_photos_title,
+                mFreeableItems));
+        setSummary(context.getString(R.string.deletion_helper_photos_summary,
+                Formatter.formatFileSize(context, mFreeableBytes), FAKE_DAYS_TO_KEEP));
+    }
+
+    /**
+     * Returns the number of bytes which can be cleared by the deletion service.
+     * @return The number of bytes.
+     */
+    public long getFreeableBytes() {
+        return mChecked ? mFreeableBytes : 0;
+    }
+
+    /**
+     * Register a listener to be called back on when the freeable bytes have changed.
+     * @param listener The callback listener.
+     */
+    public void registerFreeableChangedListener(DeletionType.FreeableChangedListener listener) {
+        mListener = listener;
+    }
+
+    /**
+     * Registers a deletion service to update the preference's information.
+     * @param deletionService A photo/video deletion service.
+     */
+    public void registerDeletionService(DeletionType deletionService) {
+        mDeletionService = deletionService;
+        if (mDeletionService != null) {
+            mDeletionService.registerFreeableChangedListener(this);
+        }
+    }
+
+    @Override
+    public void onFreeableChanged(int numItems, long freeableBytes) {
+        mFreeableItems = numItems;
+        mFreeableBytes = freeableBytes;
+        updatePreferenceText();
+        maybeUpdateListener();
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        mChecked = (boolean) newValue;
+        maybeUpdateListener();
+        return true;
+    }
+
+    private Drawable getIcon(Context context) {
+        final Drawable iconDrawable;
+        try {
+            Resources resources = context.getResources();
+            final int resId = resources.getIdentifier("ic_photos_black_24", "drawable",
+                    context.getPackageName());
+            iconDrawable = context.getDrawable(resId);
+        } catch (Resources.NotFoundException e) {
+            return null;
+        }
+        return iconDrawable;
+    }
+
+    private void maybeUpdateListener() {
+        if (mListener != null) {
+            mListener.onFreeableChanged(mFreeableItems, getFreeableBytes());
+        }
+    }
+}