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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.settings.accessibility;
     18 
     19 import android.annotation.Nullable;
     20 import android.content.ContentResolver;
     21 import android.content.res.Configuration;
     22 import android.content.res.Resources;
     23 import android.os.Bundle;
     24 import android.provider.Settings;
     25 import com.android.internal.logging.MetricsProto.MetricsEvent;
     26 import com.android.settings.PreviewSeekBarPreferenceFragment;
     27 import com.android.settings.R;
     28 
     29 /**
     30  * Preference fragment used to control font size.
     31  */
     32 public class ToggleFontSizePreferenceFragment extends PreviewSeekBarPreferenceFragment {
     33 
     34     private float[] mValues;
     35 
     36     @Override
     37     public void onCreate(@Nullable Bundle savedInstanceState) {
     38         super.onCreate(savedInstanceState);
     39 
     40         mActivityLayoutResId = R.layout.font_size_activity;
     41         mPreviewSampleResIds = new int[]{R.layout.font_size_preview};
     42 
     43         Resources res = getContext().getResources();
     44         final ContentResolver resolver = getContext().getContentResolver();
     45         // Mark the appropriate item in the preferences list.
     46         mEntries = res.getStringArray(R.array.entries_font_size);
     47         final String[] strEntryValues = res.getStringArray(R.array.entryvalues_font_size);
     48         final float currentScale =
     49                 Settings.System.getFloat(resolver, Settings.System.FONT_SCALE, 1.0f);
     50         mInitialIndex = fontSizeValueToIndex(currentScale, strEntryValues);
     51         mValues = new float[strEntryValues.length];
     52         for (int i = 0; i < strEntryValues.length; ++i) {
     53             mValues[i] = Float.parseFloat(strEntryValues[i]);
     54         }
     55     }
     56 
     57     @Override
     58     protected Configuration createConfig(Configuration origConfig, int index) {
     59         // Populate the sample layouts.
     60         final Configuration config = new Configuration(origConfig);
     61         config.fontScale = mValues[index];
     62         return config;
     63     }
     64 
     65     /**
     66      * Persists the selected font size.
     67      */
     68     @Override
     69     protected void commit() {
     70         if (getContext() == null) return;
     71         final ContentResolver resolver = getContext().getContentResolver();
     72         Settings.System.putFloat(resolver, Settings.System.FONT_SCALE, mValues[mCurrentIndex]);
     73     }
     74 
     75     @Override
     76     protected int getMetricsCategory() {
     77         return MetricsEvent.ACCESSIBILITY_FONT_SIZE;
     78     }
     79 
     80     /**
     81      *  Utility function that returns the index in a string array with which the represented value is
     82      *  the closest to a given float value.
     83      */
     84     public static int fontSizeValueToIndex(float val, String[] indices) {
     85         float lastVal = Float.parseFloat(indices[0]);
     86         for (int i=1; i<indices.length; i++) {
     87             float thisVal = Float.parseFloat(indices[i]);
     88             if (val < (lastVal + (thisVal-lastVal)*.5f)) {
     89                 return i-1;
     90             }
     91             lastVal = thisVal;
     92         }
     93         return indices.length-1;
     94     }
     95 
     96 }
     97