1/*
2 * Copyright (C) 2016 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
17package com.android.setupwizardlib.view;
18
19import android.annotation.TargetApi;
20import android.content.Context;
21import android.content.res.TypedArray;
22import android.os.Build.VERSION_CODES;
23import android.util.AttributeSet;
24import android.widget.FrameLayout;
25
26import com.android.setupwizardlib.R;
27
28/**
29 * A FrameLayout subclass that has an "intrinsic size", which is the size it wants to be if that is
30 * within the constraints given by the parent. The intrinsic size can be set with the
31 * {@code android:width} and {@code android:height} attributes in XML.
32 *
33 * Note that for the intrinsic size to be meaningful, {@code android:layout_width} and/or
34 * {@code android:layout_height} will need to be {@code wrap_content}.
35 */
36public class IntrinsicSizeFrameLayout extends FrameLayout {
37
38    private int mIntrinsicHeight = 0;
39    private int mIntrinsicWidth = 0;
40
41    public IntrinsicSizeFrameLayout(Context context) {
42        super(context);
43        init(context, null, 0);
44    }
45
46    public IntrinsicSizeFrameLayout(Context context, AttributeSet attrs) {
47        super(context, attrs);
48        init(context, attrs, 0);
49    }
50
51    @TargetApi(VERSION_CODES.HONEYCOMB)
52    public IntrinsicSizeFrameLayout(Context context, AttributeSet attrs, int defStyleAttr) {
53        super(context, attrs, defStyleAttr);
54        init(context, attrs, defStyleAttr);
55    }
56
57    private void init(Context context, AttributeSet attrs, int defStyleAttr) {
58        final TypedArray a = context.obtainStyledAttributes(attrs,
59                R.styleable.SuwIntrinsicSizeFrameLayout, defStyleAttr, 0);
60        mIntrinsicHeight =
61                a.getDimensionPixelSize(R.styleable.SuwIntrinsicSizeFrameLayout_android_height, 0);
62        mIntrinsicWidth =
63                a.getDimensionPixelSize(R.styleable.SuwIntrinsicSizeFrameLayout_android_width, 0);
64        a.recycle();
65    }
66
67    @Override
68    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
69        super.onMeasure(getIntrinsicMeasureSpec(widthMeasureSpec, mIntrinsicWidth),
70                getIntrinsicMeasureSpec(heightMeasureSpec, mIntrinsicHeight));
71    }
72
73    private int getIntrinsicMeasureSpec(int measureSpec, int intrinsicSize) {
74        if (intrinsicSize <= 0) {
75            // Intrinsic size is not set, just return the original spec
76            return measureSpec;
77        }
78        final int mode = MeasureSpec.getMode(measureSpec);
79        final int size = MeasureSpec.getSize(measureSpec);
80        if (mode == MeasureSpec.UNSPECIFIED) {
81            // Parent did not give any constraint, so we'll be the intrinsic size
82            return MeasureSpec.makeMeasureSpec(mIntrinsicHeight, MeasureSpec.EXACTLY);
83        } else if (mode == MeasureSpec.AT_MOST) {
84            // If intrinsic size is within parents constraint, take the intrinsic size.
85            // Otherwise take the parents size because that's closest to the intrinsic size.
86            return MeasureSpec.makeMeasureSpec(Math.min(size, mIntrinsicHeight),
87                    MeasureSpec.EXACTLY);
88        }
89        // Parent specified EXACTLY, or in all other cases, just return the original spec
90        return measureSpec;
91    }
92}
93