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
onCreate(@ullable Bundle savedInstanceState)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
createConfig(Configuration origConfig, int index)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
commit()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
getMetricsCategory()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      */
fontSizeValueToIndex(float val, String[] indices)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