布局文件的逐行详细解读

总览

源码

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/mainConstraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:animateLayoutChanges="true"
    tools:context=".activities.MainActivity">

    <View
        android:id="@+id/top_background"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="?attr/foreground_color"
        app:layout_constraintBottom_toTopOf="@+id/inputHorizontalScrollView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <HorizontalScrollView
        android:id="@+id/inputHorizontalScrollView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="?attr/foreground_color"
        android:overScrollMode="never"
        android:scrollbars="none"
        app:layout_constraintBottom_toTopOf="@+id/guideline1"
        app:layout_constraintTop_toBottomOf="@+id/menuButton">

        <EditText
            android:id="@+id/input"
            style="@style/RobotoFontCondensedMedium"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_gravity="right"
            android:autofillHints="false"
            android:background="?attr/foreground_color"
            android:inputType="textNoSuggestions"
            android:maxLength="10000"
            android:paddingHorizontal="10dp"
            android:singleLine="true"
            android:text=""
            android:textAlignment="textEnd"
            android:textColor="?attr/text_color"
            android:textSize="55sp"
            tools:ignore="RtlCompat" />

    </HorizontalScrollView>

    <!-- <EditText
        android:id="@+id/resultDisplay"
        style="@style/RobotoFontCondensedMedium"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:scrollHorizontally="true"
        android:clickable="false"
        android:cursorVisible="false"
        android:focusable="false"
        android:singleLine="true"
        android:background="?attr/foreground_color"
        android:inputType="textNoSuggestions"
        android:text=""
        android:textColor="?attr/text_second_color"
        android:layout_weight="1"
        android:textAlignment="textEnd"
        android:textSize="35sp"
        android:paddingHorizontal="10dp"
        android:paddingBottom="4dp"
        app:layout_constraintBottom_toTopOf="@+id/guideline2"
        app:layout_constraintTop_toTopOf="@+id/guideline1" /> -->

    <HorizontalScrollView
        android:id="@+id/resultDisplayHorizontalScrollView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="?attr/foreground_color"
        android:fillViewport="true"
        android:overScrollMode="never"
        android:scrollbars="none"
        app:layout_constraintBottom_toTopOf="@+id/guideline2"
        app:layout_constraintTop_toTopOf="@+id/guideline1">

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="end"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/resultDisplay"
                style="@style/RobotoFontCondensedMedium"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:background="?attr/foreground_color"
                android:paddingHorizontal="10dp"
                android:paddingBottom="4dp"
                android:scrollHorizontally="true"
                android:singleLine="true"
                android:text=""
                android:textAlignment="textEnd"
                android:textColor="?attr/text_second_color"
                android:textIsSelectable="true"
                android:textSize="35sp" />

        </LinearLayout>

    </HorizontalScrollView>

    <com.sothree.slidinguppanel.SlidingUpPanelLayout
        android:id="@+id/sliding_layout"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:gravity="top"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/resultDisplayHorizontalScrollView"
        app:umanoPanelHeight="41dp"
        app:umanoScrollableView="@id/history_recylcle_view"
        app:umanoShadowHeight="0dp"
        tools:ignore="MissingConstraints">


        <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/constraintLayout2"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".activities.MainActivity">

            <TableLayout
                android:id="@+id/tableLayout"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:paddingHorizontal="8dp"
                android:paddingTop="12dp"
                android:paddingBottom="0dp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintTop_toTopOf="parent">

                <TableRow
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginBottom="1dp"
                    android:layout_weight="0">

                    <Button
                        android:id="@+id/squareButton"
                        android:contentDescription="@string/squareDesc"
                        style="@style/CalculatorButton.Function"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_margin="0dp"
                        android:layout_weight="1"
                        android:onClick="squareButton"
                        android:text="@string/square"
                        android:textSize="26sp" />

                    <Button
                        android:id="@+id/piButton"
                        style="@style/CalculatorButton.Function"
                        android:contentDescription="@string/piDesc"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_margin="0dp"
                        android:layout_weight="1"
                        android:onClick="piButton"
                        android:text="@string/pi"
                        android:textSize="26sp" />

                    <ImageButton
                        android:id="@+id/exponentButton"
                        style="@style/CalculatorButton.Function"
                        android:contentDescription="@string/exponentDesc"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_margin="0dp"
                        android:layout_weight="1"
                        android:onClick="exponentButton"
                        app:srcCompat="@drawable/exponent" />

                    <Button
                        android:id="@+id/factorialButton"
                        style="@style/CalculatorButton.Function"
                        android:contentDescription="@string/factorialDesc"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_margin="0dp"
                        android:layout_weight="1"
                        android:onClick="factorialButton"
                        android:text="@string/factorial"
                        android:textSize="26sp" />

                    <ImageButton
                        android:id="@+id/scientistModeSwitchButton"
                        style="@style/Widget.AppCompat.Button.Borderless"
                        android:contentDescription="@string/scientificModeSwitchDesc"
                        android:layout_width="0dp"
                        android:layout_height="match_parent"
                        android:layout_margin="0dp"
                        android:layout_weight="0.6"
                        android:background="@drawable/circle"
                        android:backgroundTint="?attr/foreground_color"
                        android:onClick