如何创建包含在小部件链中的“方形”ConstraintLayout？

Question

我尝试通过扩展ConstraintLayout 类来创建一个“正方形”ConstraintLayout，如下所示：

class SCConstraintLayout extends android.support.constraint.ConstraintLayout {
public SCConstraintLayout(Context context) {
    super(context);
}

public SCConstraintLayout(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public SCConstraintLayout(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int chosenDimension = 0;
    int mode = 0;

    if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
        chosenDimension = MeasureSpec.getSize(heightMeasureSpec);
        mode = MeasureSpec.getMode(heightMeasureSpec);
    } else {
        chosenDimension = MeasureSpec.getSize(widthMeasureSpec);
        mode = MeasureSpec.getMode(widthMeasureSpec);
    }

    int side = MeasureSpec.makeMeasureSpec(chosenDimension, mode);

    super.onMeasure(side, side);
    setMeasuredDimension(side, side);
}
}

如果我将具有此自定义类的小部件包含到小部件链中，例如在以下面向横向的布局中

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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/scMainFrame"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="?attr/actionBarSize"
app:layout_optimizationLevel="chains"
tools:context=".MainActivity"
tools:layout_behavior="@string/appbar_scrolling_view_behavior">

<!-- gridFrame -->
<android.support.constraint.ConstraintLayout
    android:id="@+id/gridFrame"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:layout_constraintHorizontal_chainStyle="spread_inside"
    app:layout_constraintVertical_chainStyle="spread_inside"
    app:layout_optimizationLevel="chains"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toLeftOf="@+id/Report"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintBottom_toBottomOf="parent"
    >

    <!-- column headers  -->
    <android.support.constraint.ConstraintLayout
        android:id="@+id/colHeaders"
        android:layout_width="0dp"
        android:layout_height="14dp"
        android:orientation="horizontal"
        app:layout_constraintVertical_chainStyle="spread_inside"
        app:layout_optimizationLevel="chains"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/SCFrame"
        app:layout_constraintLeft_toLeftOf="@+id/SCFrame"
        app:layout_constraintRight_toRightOf="@+id/SCFrame"
        >

        <TextView
            android:id="@+id/textView0"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:gravity="center"
            android:text="A"
            android:background="#FF0000"
            app:layout_constraintHorizontal_chainStyle="spread_inside"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            />
        </android.support.constraint.ConstraintLayout>

    <!-- row headers  -->
    <android.support.constraint.ConstraintLayout
        android:id="@+id/rowHeaders"
        android:layout_width="14dp"
        android:layout_height="0dp"
        android:orientation="vertical"
        app:layout_constraintHorizontal_chainStyle="spread_inside"
        app:layout_optimizationLevel="chains"
        app:layout_constraintTop_toTopOf="@+id/SCFrame"
        app:layout_constraintBottom_toBottomOf="@+id/SCFrame"
        app:layout_constraintRight_toLeftOf="@+id/SCFrame"
        app:layout_constraintLeft_toLeftOf="parent"
        >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:gravity="center"
            android:text="1"
            android:background="#FF0000"
            app:layout_constraintVertical_chainStyle="spread_inside"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            />
        </android.support.constraint.ConstraintLayout>


        <be.ema.sclibrary.SCConstraintLayout
            android:id="@+id/SCFrame"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:background="#00FF00"
            app:layout_constraintLeft_toRightOf="@+id/rowHeaders"
            app:layout_constraintTop_toBottomOf="@id/colHeaders"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"
            >

            <TextView
                android:id="@+id/A1"
                android:layout_width="0dp"
                android:layout_height="0dp"
                android:text="this is A1"
                android:background="#0000FF"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintBottom_toBottomOf="parent"
                />
        </be.ema.sclibrary.SCConstraintLayout>
    </android.support.constraint.ConstraintLayout>

<TextView
    android:id="@+id/Report"
    android:layout_width="200dp"
    android:layout_height="0dp"
    android:text="This is the report"
    android:background="#FFFF00"
    app:layout_constraintLeft_toRightOf="@+id/gridFrame"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintBottom_toBottomOf="parent"
    />

</android.support.constraint.ConstraintLayout>

如果我将它显示在 Android Studio 模拟器中的“Nexus 6”上，它看起来就像 SCFrame 只是部分正方形：

• A1TextView 是方形的（即它的宽度等于它的高度）
• 但是SCFrame 本身的宽度与高度不同

我应该如何更改 SCConstraintLayout 类或 xml 布局以在设备上显示 SCFrame 视图时完全正方形（即其宽度等于其高度）？

注意：在我的实际应用程序中，SCFrame 有几行和几列。还有其他几个小部件，例如按钮和文本视图，而不是 Report 文本视图。

Answer 1

您只需要将顶层设置为 ConstraintLayout。不需要嵌套类和自定义类。至于方形的TextView，可以使用纵横比属性。