嵌套权重警告

Question

我在 Android Studio 中的布局上收到此警告：

Nested weights are bad for performance less...
Layout weights require a widget to be measured twice. When a LinearLayout with non-zero weights is nested inside another LinearLayout with non-zero weights, then the number of measurements increase exponentially.
Issue id: NestedWeights

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        style="?android:attr/buttonBarStyle">
        <Button
            android:id="@+id/b1"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="2dp"
            android:layout_weight="1"
            android:background="#093A3E"
            android:foreground="?attr/selectableItemBackground"
            android:text="One"
            android:textAllCaps="false"
            android:textColor="#fff"
            android:textSize="18sp"
            style="?android:attr/buttonBarButtonStyle" />
        <Button
            android:id="@+id/b2"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="2dp"
            android:layout_weight="1"
            android:background="#3AAFB9"
            android:foreground="?attr/selectableItemBackground"
            android:text="Two"
            android:textAllCaps="false"
            android:textColor="#fff"
            android:textSize="18sp"
            style="?android:attr/buttonBarButtonStyle" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="horizontal"
        style="?android:attr/buttonBarStyle">
        <Button
            android:id="@+id/b6"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_margin="2dp"
            android:foreground="?attr/selectableItemBackground"
            android:layout_weight="1"
            android:background="#64E9EE"
            android:text="Three"
            android:textAllCaps="false"
            android:textColor="#fff"
            android:textSize="18sp"
            style="?android:attr/buttonBarButtonStyle" />
        <Button
            android:id="@+id/b7"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:foreground="?attr/selectableItemBackground"
            android:layout_margin="2dp"
            android:layout_weight="1"
            android:background="#97C8EB"
            android:text="Four"
            android:textAllCaps="false"
            android:textColor="#fff"
            android:textSize="18sp"
            style="?android:attr/buttonBarButtonStyle" />
    </LinearLayout>
</LinearLayout>

结果：

如何避免此警告并获得相同的结果？谢谢

Answer 1

为了更好的方法，我使用 ConstraintLayout

发布了下面的代码

对于您的方法，这里是解决方案从布局中删除 android:layout_weight="1"

您应该按照以下顺序重新格式化您的代码。

LinearLayout（根）方向垂直（包含 2 个其他 LinearLayout）
LinearLayout（顶部，内部根）方向水平（按钮权重为 1）
LinearLayout（底部，内部根）水平方向（按钮权重为 1）

更好的方法是使用 ConstraintLayout

<?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"
    android:layout_width="match_parent" android:layout_height="match_parent">

<Button
    android:id="@+id/button2"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginStart="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    android:text="1"
    app:layout_constraintBottom_toTopOf="@+id/button4"
    app:layout_constraintEnd_toStartOf="@+id/button3"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<Button
    android:id="@+id/button5"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    android:text="4"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toEndOf="@+id/button4"
    app:layout_constraintTop_toBottomOf="@+id/button3" />

<Button
    android:id="@+id/button4"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    android:text="3"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toStartOf="@+id/button5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/button2" />

<Button
    android:id="@+id/button3"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="8dp"
    android:text="2"
    app:layout_constraintBottom_toTopOf="@+id/button5"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toEndOf="@+id/button2"
    app:layout_constraintTop_toTopOf="parent" />

  </android.support.constraint.ConstraintLayout>

嵌套权重警告

Nested weights warning

android

warnings

android-layout

android-studio