1 /*
2  * Copyright (C) 2020 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.content.Context;
20 import android.util.AttributeSet;
21 import android.view.View;
22 import android.view.ViewTreeObserver;
23 import android.widget.FrameLayout;
24 import android.widget.ListView;
25 
26 import androidx.preference.Preference;
27 import androidx.preference.PreferenceViewHolder;
28 
29 import com.android.settings.R;
30 
31 /** Preference that easier preview by matching name to color. */
32 public class PaletteListPreference extends Preference {
33 
34     private ListView mListView;
35     private ViewTreeObserver.OnPreDrawListener mPreDrawListener;
36 
37     /**
38      * Constructs a new PaletteListPreference with the given context's theme and the supplied
39      * attribute set.
40      *
41      * @param context The Context this is associated with, through which it can access the current
42      *                theme, resources, etc.
43      * @param attrs The attributes of the XML tag that is inflating the view.
44      */
PaletteListPreference(Context context, AttributeSet attrs)45     public PaletteListPreference(Context context, AttributeSet attrs) {
46         this(context, attrs, 0);
47     }
48 
49     /**
50      * Constructs a new PaletteListPreference with the given context's theme, the supplied
51      * attribute set, and default style attribute.
52      *
53      * @param context The Context this is associated with, through which it can access the
54      *                current theme, resources, etc.
55      * @param attrs The attributes of the XML tag that is inflating the view.
56      * @param defStyleAttr An attribute in the current theme that contains a reference to a style
57      *                     resource that supplies default
58      *                     values for the view. Can be 0 to not look for
59      *                     defaults.
60      */
PaletteListPreference(Context context, AttributeSet attrs, int defStyleAttr)61     public PaletteListPreference(Context context, AttributeSet attrs, int defStyleAttr) {
62         super(context, attrs, defStyleAttr);
63         setLayoutResource(R.layout.daltonizer_preview);
64         initPreDrawListener();
65     }
66 
67     @Override
onBindViewHolder(PreferenceViewHolder holder)68     public void onBindViewHolder(PreferenceViewHolder holder) {
69         super.onBindViewHolder(holder);
70 
71         final View rootView = holder.itemView;
72         mListView = rootView.findViewById(R.id.palette_listView);
73         if (mPreDrawListener != null) {
74             mListView.getViewTreeObserver().addOnPreDrawListener(mPreDrawListener);
75         }
76     }
77 
initPreDrawListener()78     private void initPreDrawListener() {
79         mPreDrawListener = new ViewTreeObserver.OnPreDrawListener() {
80             @Override
81             public boolean onPreDraw() {
82                 if (mListView == null) {
83                     return false;
84                 }
85 
86                 final int listViewHeight = mListView.getMeasuredHeight();
87                 final int listViewWidth = mListView.getMeasuredWidth();
88 
89                 // Removes the callback after get result of measure view.
90                 final ViewTreeObserver viewTreeObserver = mListView.getViewTreeObserver();
91                 if (viewTreeObserver.isAlive()) {
92                     viewTreeObserver.removeOnPreDrawListener(this);
93                 }
94                 mPreDrawListener = null;
95 
96                 // Resets layout parameters to display whole items from listView.
97                 final FrameLayout.LayoutParams layoutParams =
98                         (FrameLayout.LayoutParams) mListView.getLayoutParams();
99                 layoutParams.height = listViewHeight * mListView.getAdapter().getCount();
100                 layoutParams.width = listViewWidth;
101                 mListView.setLayoutParams(layoutParams);
102 
103                 return true;
104             }
105         };
106     }
107 }
108