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1 /*
2  * Copyright (C) 2022 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.systemui.util
18 
19 import android.content.Context
20 import android.util.AttributeSet
21 import android.view.Choreographer
22 import androidx.constraintlayout.motion.widget.MotionLayout
23 import com.android.app.tracing.traceSection
24 
25 /**
26  * [MotionLayout] that avoids remeasuring with the same inputs in the same frame.
27  *
28  * This is important when this view is the child of a view that performs more than one measure pass
29  * (e.g. [LinearLayout] or [ConstraintLayout]). In those cases, if this view is measured with the
30  * same inputs in the same frame, we use the last result.
31  */
32 class NoRemeasureMotionLayout @JvmOverloads constructor(
33     context: Context,
34     attrs: AttributeSet?,
35     defStyle: Int = 0
36 ) : MotionLayout(context, attrs, defStyle) {
37 
38     private var lastWidthSpec: Int? = null
39     private var lastHeightSpec: Int? = null
40     private var lastFrame: Long? = null
41 
onMeasurenull42     override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
43         if (
44             lastWidthSpec == widthMeasureSpec &&
45             lastHeightSpec == heightMeasureSpec &&
46             Choreographer.getMainThreadInstance()?.frameTime == lastFrame
47         ) {
48             setMeasuredDimension(measuredWidth, measuredHeight)
49             return
50         }
51         traceSection("NoRemeasureMotionLayout - measure") {
52             super.onMeasure(widthMeasureSpec, heightMeasureSpec)
53             lastWidthSpec = widthMeasureSpec
54             lastHeightSpec = heightMeasureSpec
55             lastFrame = Choreographer.getMainThreadInstance()?.frameTime
56         }
57     }
58 }
59