Display Settings: Better font size control

Use a SeekBar instead of a list/spinner to determine the font scaling.
For consistency, an approximate size (small, normal, etc.)
 and the exact percentage are displayed.
Show a preview of the selected font size immediately

Ported from CM 10.2, squashed commits 46678 and 49167.
Credit to Veeti Paaananen for the latter commit.

Change-Id: I754d7fdcaf27c23dfccf9d56291956e70b23f63e

8 files changed, 327 insertions, 174 deletions

diff --git a/res/layout/preference_dialog_fontsize.xml b/res/layout/preference_dialog_fontsize.xml
new file mode 100644
index 0000000..f209d46
--- /dev/null
+++ b/res/layout/preference_dialog_fontsize.xml
@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2008 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.
+-->
+
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:settings="http://schemas.android.com/apk/res/com.android.settings"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:padding="12dp">
+
+        <!-- Static height enough to accommodate the text views in their biggest possible size,
+        without having the dialog resize itself at any point. -->
+        <LinearLayout android:id="@+id/container"
+                 android:orientation="vertical"
+                 android:layout_width="match_parent"
+                 android:layout_height="64dp"
+                 android:gravity="center_horizontal|center_vertical">
+
+                <TextView android:id="@+id/description"
+                        android:text="@string/font_size_sample"
+                        android:layout_width="wrap_content"
+                        android:layout_height="wrap_content"
+                        android:textAppearance="?android:textAppearanceLarge" />
+
+                <TextView android:id="@+id/percentage"
+                        android:layout_width="wrap_content"
+                        android:layout_height="wrap_content"
+                        android:textAppearance="?android:textAppearanceSmall" />
+
+        </LinearLayout>
+
+        <com.android.settings.IntervalSeekBar android:id="@+id/font_size"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:padding="8dp"
+                android:layout_below="@+id/container"
+                settings:min="0.85"
+                settings:max="1.30"
+                settings:defaultValue="1.00"
+                settings:digits="2" />
+
+</RelativeLayout>
diff --git a/res/values/attrs.xml b/res/values/attrs.xml
index 4b607be..d774622 100644
--- a/res/values/attrs.xml
+++ b/res/values/attrs.xml
@@ -118,4 +118,11 @@
         <attr name="android:entries" />
         <attr name="android:entryValues" />
     </declare-styleable>
+
+    <declare-styleable name="IntervalSeekBar">
+        <attr name="min" format="float" />
+        <attr name="max" format="float" />
+        <attr name="defaultValue" format="float" />
+        <attr name="digits" format="integer" />
+    </declare-styleable>
 </resources>
diff --git a/res/values/cm_strings.xml b/res/values/cm_strings.xml
index 49672e2..329f657 100644
--- a/res/values/cm_strings.xml
+++ b/res/values/cm_strings.xml
@@ -417,4 +417,8 @@
     <!-- Turn on display when power connected; turn off display when power disconnected -->
     <string name="wake_when_plugged_or_unplugged_title">Wake on plug</string>
     <string name="wake_when_plugged_or_unplugged_summary">Turn the screen on when connecting or disconnecting a power source</string>
+
+    <!-- Font size sample text. This needs to be a very short string, as it is shown in
+    multiple font sizes in a limited amount of space. -->
+    <string name="font_size_sample">Sample</string>
 </resources>
diff --git a/res/xml/display_settings.xml b/res/xml/display_settings.xml
index 3912d37..1963055 100644
--- a/res/xml/display_settings.xml
+++ b/res/xml/display_settings.xml
@@ -79,13 +79,11 @@
                 android:summary="@string/tap_to_wake_summary"
                 android:persistent="false" />
 
-        <com.android.settings.WarnedListPreference
+        <com.android.settings.FontDialogPreference
                 android:key="font_size"
                 android:title="@string/title_font_size"
                 settings:keywords="@string/keywords_display_font_size"
                 android:summary="@string/summary_font_size"
-                android:entries="@array/entries_font_size"
-                android:entryValues="@array/entryvalues_font_size"
                 android:dialogTitle="@string/dialog_title_font_size" />
 
         <com.android.settings.DropDownPreference
diff --git a/src/com/android/settings/Display.java b/src/com/android/settings/Display.java
deleted file mode 100644
index fa29318..0000000
--- a/src/com/android/settings/Display.java
+++ /dev/null
@@ -1,138 +0,0 @@
-/*
- * Copyright (C) 2006 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.app.Activity;
-import android.app.ActivityManagerNative;
-import android.content.res.Configuration;
-import android.content.res.Resources;
-import android.content.res.TypedArray;
-import android.os.Bundle;
-import android.os.RemoteException;
-import android.util.DisplayMetrics;
-import android.util.TypedValue;
-import android.view.View;
-import android.widget.ArrayAdapter;
-import android.widget.Button;
-import android.widget.Spinner;
-import android.widget.TextView;
-
-
-public class Display extends Activity implements View.OnClickListener {
-    @Override
-    public void onCreate(Bundle icicle) {
-        super.onCreate(icicle);
-
-        setContentView(R.layout.display);
-
-        mFontSize = (Spinner) findViewById(R.id.fontSize);
-        mFontSize.setOnItemSelectedListener(mFontSizeChanged);
-        String[] states = new String[3];
-        Resources r = getResources();
-        states[0] = r.getString(R.string.small_font);
-        states[1] = r.getString(R.string.medium_font);
-        states[2] = r.getString(R.string.large_font);
-        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
-                android.R.layout.simple_spinner_item, states);
-        adapter.setDropDownViewResource(
-                android.R.layout.simple_spinner_dropdown_item);
-        mFontSize.setAdapter(adapter);
-
-        mPreview = (TextView) findViewById(R.id.preview);
-        mPreview.setText(r.getText(R.string.font_size_preview_text));
-
-        Button save = (Button) findViewById(R.id.save);
-        save.setText(r.getText(R.string.font_size_save));
-        save.setOnClickListener(this);
-
-        mTextSizeTyped = new TypedValue();
-        TypedArray styledAttributes = 
-            obtainStyledAttributes(android.R.styleable.TextView);
-        styledAttributes.getValue(android.R.styleable.TextView_textSize,
-                mTextSizeTyped);
-
-        DisplayMetrics metrics = getResources().getDisplayMetrics();
-        mDisplayMetrics = new DisplayMetrics();
-        mDisplayMetrics.density = metrics.density;
-        mDisplayMetrics.heightPixels = metrics.heightPixels;
-        mDisplayMetrics.scaledDensity = metrics.scaledDensity;
-        mDisplayMetrics.widthPixels = metrics.widthPixels;
-        mDisplayMetrics.xdpi = metrics.xdpi;
-        mDisplayMetrics.ydpi = metrics.ydpi;
-        
-        styledAttributes.recycle();
-    }
-
-    @Override
-    public void onResume() {
-        super.onResume();
-        try {
-            mCurConfig.updateFrom(
-                ActivityManagerNative.getDefault().getConfiguration());
-        } catch (RemoteException e) {
-        }
-        if (mCurConfig.fontScale < 1) {
-            mFontSize.setSelection(0);
-        } else if (mCurConfig.fontScale > 1) {
-            mFontSize.setSelection(2);
-        } else {
-            mFontSize.setSelection(1);
-        }
-        updateFontScale();
-    }
-
-    private void updateFontScale() {
-        mDisplayMetrics.scaledDensity = mDisplayMetrics.density *
-                mCurConfig.fontScale;
-
-        float size = mTextSizeTyped.getDimension(mDisplayMetrics);
-        mPreview.setTextSize(TypedValue.COMPLEX_UNIT_PX, size);
-    }
-
-    public void onClick(View v) {
-        try {
-            ActivityManagerNative.getDefault().updatePersistentConfiguration(mCurConfig);
-        } catch (RemoteException e) {
-        }
-        finish();
-    }
-
-    private Spinner.OnItemSelectedListener mFontSizeChanged
-                                    = new Spinner.OnItemSelectedListener() {
-        public void onItemSelected(android.widget.AdapterView av, View v,
-                                    int position, long id) {
-            if (position == 0) {
-                mCurConfig.fontScale = .75f;
-            } else if (position == 2) {
-                mCurConfig.fontScale = 1.25f;
-            } else {
-                mCurConfig.fontScale = 1.0f;
-            }
-
-            updateFontScale();
-        }
-
-        public void onNothingSelected(android.widget.AdapterView av) {
-        }
-    };
-
-    private Spinner mFontSize;
-    private TextView mPreview;
-    private TypedValue mTextSizeTyped;
-    private DisplayMetrics mDisplayMetrics;
-    private Configuration mCurConfig = new Configuration();
-}
diff --git a/src/com/android/settings/DisplaySettings.java b/src/com/android/settings/DisplaySettings.java
index 01eed08..66af458 100644
--- a/src/com/android/settings/DisplaySettings.java
+++ b/src/com/android/settings/DisplaySettings.java
@@ -88,7 +88,7 @@ public class DisplaySettings extends SettingsPreferenceFragment implements
 
     private static final int DLG_GLOBAL_CHANGE_WARNING = 1;
 
-    private WarnedListPreference mFontSizePref;
+    private FontDialogPreference mFontSizePref;
 
     private final Configuration mCurConfig = new Configuration();
 
@@ -130,7 +130,7 @@ public class DisplaySettings extends SettingsPreferenceFragment implements
         disableUnusableTimeouts(mScreenTimeoutPreference);
         updateTimeoutPreferenceDescription(currentTimeout);
 
-        mFontSizePref = (WarnedListPreference) findPreference(KEY_FONT_SIZE);
+        mFontSizePref = (FontDialogPreference) findPreference(KEY_FONT_SIZE);
         mFontSizePref.setOnPreferenceChangeListener(this);
         mFontSizePref.setOnPreferenceClickListener(this);
 
@@ -312,37 +312,6 @@ public class DisplaySettings extends SettingsPreferenceFragment implements
         screenTimeoutPreference.setEnabled(revisedEntries.size() > 0);
     }
 
-    int floatToIndex(float val) {
-        String[] indices = getResources().getStringArray(R.array.entryvalues_font_size);
-        float lastVal = Float.parseFloat(indices[0]);
-        for (int i=1; i<indices.length; i++) {
-            float thisVal = Float.parseFloat(indices[i]);
-            if (val < (lastVal + (thisVal-lastVal)*.5f)) {
-                return i-1;
-            }
-            lastVal = thisVal;
-        }
-        return indices.length-1;
-    }
-
-    public void readFontSizePreference(ListPreference pref) {
-        try {
-            mCurConfig.updateFrom(ActivityManagerNative.getDefault().getConfiguration());
-        } catch (RemoteException e) {
-            Log.w(TAG, "Unable to retrieve font size");
-        }
-
-        // mark the appropriate item in the preferences list
-        int index = floatToIndex(mCurConfig.fontScale);
-        pref.setValueIndex(index);
-
-        // report the current size in the summary text
-        final Resources res = getResources();
-        String[] fontSizeNames = res.getStringArray(R.array.entries_font_size);
-        pref.setSummary(String.format(res.getString(R.string.summary_font_size),
-                fontSizeNames[index]));
-    }
-
     @Override
     public void onResume() {
         super.onResume();
@@ -422,6 +391,22 @@ public class DisplaySettings extends SettingsPreferenceFragment implements
         }
     }
 
+    /**
+     * Reads the current font size and sets the value in the summary text
+     */
+    public void readFontSizePreference(Preference pref) {
+        try {
+            mCurConfig.updateFrom(ActivityManagerNative.getDefault().getConfiguration());
+        } catch (RemoteException e) {
+            Log.w(TAG, "Unable to retrieve font size");
+        }
+
+        // report the current size in the summary text
+        final Resources res = getResources();
+        String fontDesc = FontDialogPreference.getFontSizeDescription(res, mCurConfig.fontScale);
+        pref.setSummary(getString(R.string.summary_font_size, fontDesc));
+    }
+
     public void writeFontSizePreference(Object objValue) {
         try {
             mCurConfig.fontScale = Float.parseFloat(objValue.toString());
diff --git a/src/com/android/settings/FontDialogPreference.java b/src/com/android/settings/FontDialogPreference.java
new file mode 100644
index 0000000..e9906e0
--- /dev/null
+++ b/src/com/android/settings/FontDialogPreference.java
@@ -0,0 +1,156 @@
+package com.android.settings;
+
+import android.app.ActivityManagerNative;
+import android.content.Context;
+import android.content.res.Configuration;
+import android.content.res.Resources;
+import android.content.res.TypedArray;
+import android.os.RemoteException;
+import android.preference.DialogPreference;
+import android.preference.Preference;
+import android.provider.Settings;
+import android.util.AttributeSet;
+import android.util.DisplayMetrics;
+import android.util.Log;
+import android.util.TypedValue;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.SeekBar;
+import android.widget.TextView;
+
+public class FontDialogPreference extends DialogPreference
+    implements SeekBar.OnSeekBarChangeListener {
+
+    private TextView mDescriptionText;
+    private TextView mPercentageText;
+    private IntervalSeekBar mSeekBar;
+
+    private DisplayMetrics mDisplayMetrics;
+    private int mLargeTextSp;
+    private int mSmallTextSp;
+
+    public FontDialogPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        setPositiveButtonText(android.R.string.ok);
+        setNegativeButtonText(android.R.string.cancel);
+
+        initDisplayMetrics();
+
+        setDialogLayoutResource(R.layout.preference_dialog_fontsize);
+        setDialogTitle(null); // Hide the title bar
+    }
+
+    @Override
+    protected View onCreateDialogView() {
+        LayoutInflater inflater =
+                (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+        View view = inflater.inflate(R.layout.preference_dialog_fontsize, null);
+
+        mDescriptionText = (TextView) view.findViewById(R.id.description);
+        mPercentageText = (TextView) view.findViewById(R.id.percentage);
+
+        // Calculate original sp sizes for the text views
+        mLargeTextSp = Math.round(mDescriptionText.getTextSize() / mDisplayMetrics.scaledDensity);
+        mSmallTextSp = Math.round(mPercentageText.getTextSize() / mDisplayMetrics.scaledDensity);
+
+        mSeekBar = (IntervalSeekBar) view.findViewById(R.id.font_size);
+
+        String strFontSize = getPersistedString(String.valueOf(mSeekBar.getDefault()));
+        float fontSize = Float.parseFloat(strFontSize);
+
+        mSeekBar.setProgressFloat(fontSize);
+        mSeekBar.setOnSeekBarChangeListener(this);
+
+        setPrompt(fontSize);
+
+        return view;
+    }
+
+    private void initDisplayMetrics() {
+        DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
+        mDisplayMetrics = new DisplayMetrics();
+        mDisplayMetrics.density = metrics.density;
+        mDisplayMetrics.heightPixels = metrics.heightPixels;
+        mDisplayMetrics.scaledDensity = metrics.scaledDensity;
+        mDisplayMetrics.widthPixels = metrics.widthPixels;
+        mDisplayMetrics.xdpi = metrics.xdpi;
+        mDisplayMetrics.ydpi = metrics.ydpi;
+    }
+
+    @Override
+    protected void onDialogClosed(boolean positiveResult) {
+        if (positiveResult) {
+            // Notify the Display settings screen (parent) that the font size
+            // is about to change. This can determine whether to persist the
+            // current value
+            if (callChangeListener(mSeekBar.getProgressFloat())) {
+                // Originally font scaling was a float stored as a String,
+                // so using persistFloat raises a ClassCastException
+                persistString(Float.toString(mSeekBar.getProgressFloat()));
+            }
+        }
+    }
+
+    @Override
+    protected void onClick() {
+        // Ignore this until an explicit call to click()
+    }
+
+    public void click() {
+        super.onClick();
+    }
+
+    /**
+     * Get an approximate description for the font size scale.
+     *  Assumes that the string arrays entries_font_size and
+     *  entryvalues_font_size have the same length and correspond to each other
+     *  i.e. they are in the same order.
+     */
+    static String getFontSizeDescription(Resources r, float val) {
+        String[] names = r.getStringArray(R.array.entries_font_size);
+        String[] indices = r.getStringArray(R.array.entryvalues_font_size);
+
+        float lastVal = Float.parseFloat(indices[0]);
+        for (int i = 1; i < indices.length; i++) {
+            float thisVal = Float.parseFloat(indices[i]);
+            if (val < (lastVal + (thisVal-lastVal)*.5f)) {
+                return names[i - 1];
+            }
+            lastVal = thisVal;
+        }
+        return names[indices.length - 1];
+    }
+
+    /**
+     * Set the TextView indicating the font scaling
+     */
+    private void setPrompt(float fontScaling) {
+        // Update the preview text
+        String percentage = Math.round(fontScaling * 100) + "%";
+        mPercentageText.setText(percentage);
+
+        // Update the preview sizes
+        mDisplayMetrics.scaledDensity = mDisplayMetrics.density * fontScaling;
+        float largeSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, mLargeTextSp,
+                mDisplayMetrics);
+        float smallSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, mSmallTextSp,
+                mDisplayMetrics);
+        mDescriptionText.setTextSize(TypedValue.COMPLEX_UNIT_PX, largeSize);
+        mPercentageText.setTextSize(TypedValue.COMPLEX_UNIT_PX, smallSize);
+    }
+
+    @Override
+    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
+        setPrompt(mSeekBar.getProgressFloat());
+    }
+
+    // Not used
+    @Override
+    public void onStartTrackingTouch(SeekBar seekBar) {
+    }
+
+    @Override
+    public void onStopTrackingTouch(SeekBar seekBar) {
+    }
+}
diff --git a/src/com/android/settings/IntervalSeekBar.java b/src/com/android/settings/IntervalSeekBar.java
new file mode 100644
index 0000000..5fbdb81
--- /dev/null
+++ b/src/com/android/settings/IntervalSeekBar.java
@@ -0,0 +1,87 @@
+package com.android.settings;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.widget.SeekBar;
+
+/**
+ * Custom SeekBar that allows setting both a minimum and maximum value.
+ * This also handles floating point values (to 2 decimal places) through
+ * integer conversions.
+ */
+public class IntervalSeekBar extends SeekBar {
+    private float mMin;
+    private float mMax;
+    private float mDefault;
+    private float mMultiplier;
+
+    public IntervalSeekBar(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        TypedArray seekBarType = context.obtainStyledAttributes(attrs,
+                R.styleable.IntervalSeekBar, 0, 0);
+
+        mMax = seekBarType.getFloat(R.styleable.IntervalSeekBar_max, 1.5f);
+        mMin = seekBarType.getFloat(R.styleable.IntervalSeekBar_min, 0.5f);
+        mDefault = seekBarType.getFloat(R.styleable.IntervalSeekBar_defaultValue, 1.0f);
+
+        int digits = seekBarType.getInt(R.styleable.IntervalSeekBar_digits, 0);
+        mMultiplier = (float) Math.pow(10, digits);
+
+        if (mMin > mMax) {
+            float temp = mMax;
+            mMax = mMin;
+            mMin = temp;
+        }
+
+        setMax(convertFloatToProgress(mMax));
+        setProgressFloat(mDefault);
+
+        seekBarType.recycle();
+    }
+
+    /*
+     * Converts from SeekBar units (which the SeekBar uses), to scale units
+     *  (which are saved).
+     *  This operation is the inverse of setFontScaling.
+     */
+    public float getProgressFloat() {
+        return (getProgress() / mMultiplier) + mMin;
+    }
+
+    /*
+     * Converts from scale units (which are saved), to SeekBar units
+     * (which the SeekBar uses). This also sets the SeekBar progress.
+     * This operation is the inverse of getProgressFloat.
+     */
+    public void setProgressFloat(float progress) {
+        setProgress(convertFloatToProgress(progress));
+    }
+
+    private int convertFloatToProgress(float value) {
+        return Math.round((value - mMin) * mMultiplier);
+    }
+
+    public float getMinimum() {
+        return mMin;
+    }
+
+    public float getMaximum() {
+        return mMax;
+    }
+
+    public float getDefault() {
+        return mDefault;
+    }
+
+    public void setMaximum(float max) {
+        mMax = max;
+        setMax(convertFloatToProgress(mMax));
+    }
+
+    public void setMinimum(float min) {
+        mMin = min;
+    }
+}