Extract magnification capabilities from MagnificationSettingsFragment into a new class.

* To increase single responsibility of MagnificationSettingsFragment

Bug: 168567356
Test: atest MagnificationCapabilitiesTest
Change-Id: Ic5e8a556858ac2b6ab9929b1bbdc373ce320c270

src/com/android/settings/accessibility/MagnificationCapabilities.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2020 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.accessibility;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.provider.Settings;
+
+import androidx.annotation.IntDef;
+
+import com.android.settings.R;
+
+import com.google.common.primitives.Ints;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/** Class to provide magnification capabilities. */
+public final class MagnificationCapabilities {
+
+    private static final String KEY_CAPABILITY =
+            Settings.Secure.ACCESSIBILITY_MAGNIFICATION_CAPABILITY;
+
+    /**
+     * Annotation for supported magnification mode.
+     *
+     * @see Settings.Secure#ACCESSIBILITY_MAGNIFICATION_CAPABILITY
+     */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({
+            MagnificationMode.FULLSCREEN,
+            MagnificationMode.WINDOW,
+            MagnificationMode.ALL,
+    })
+
+    public @interface MagnificationMode {
+        int FULLSCREEN = Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_FULLSCREEN;
+        int WINDOW = Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_WINDOW;
+        int ALL = Settings.Secure.ACCESSIBILITY_MAGNIFICATION_MODE_ALL;
+    }
+
+    /**
+     * Gets the summary for the given {@code capabilities}.
+     *
+     * @param context A {@link Context}.
+     * @param capabilities Magnification capabilities {@link MagnificationMode}
+     * @return The summary text represents the given capabilities
+     */
+    public static String getSummary(Context context, @MagnificationMode int capabilities) {
+        final String[] summaries = context.getResources().getStringArray(
+                R.array.magnification_mode_summaries);
+        final int[] values = context.getResources().getIntArray(
+                R.array.magnification_mode_values);
+
+        final int idx = Ints.indexOf(values, capabilities);
+        return summaries[idx == /* no index exist */ -1 ? 0 : idx];
+    }
+
+    /**
+     * Sets the magnification capabilities {@link MagnificationMode} to settings key. This
+     * overwrites any existing capabilities.
+     *
+     * @param context      A {@link Context}.
+     * @param capabilities Magnification capabilities {@link MagnificationMode}
+     */
+    public static void setCapabilities(Context context, @MagnificationMode int capabilities) {
+        final ContentResolver contentResolver = context.getContentResolver();
+
+        Settings.Secure.putIntForUser(contentResolver, KEY_CAPABILITY, capabilities,
+                contentResolver.getUserId());
+    }
+
+    /**
+     * Returns the magnification capabilities {@link MagnificationMode} from setting's key. May be
+     * default value {@link MagnificationMode#FULLSCREEN} if not set.
+     *
+     * @param context A {@link Context}.
+     * @return The magnification capabilities {@link MagnificationMode}
+     */
+    @MagnificationMode
+    public static int getCapabilities(Context context) {
+        final ContentResolver contentResolver = context.getContentResolver();
+
+        return Settings.Secure.getIntForUser(contentResolver, KEY_CAPABILITY,
+                MagnificationMode.FULLSCREEN, contentResolver.getUserId());
+    }
+
+    private MagnificationCapabilities() {}
+}