你好，我新的Android工作室，我创建新的项目与“基本活动”模板，不能理解为什么我不能拖放按钮，我想在activity_main.xml总是停留在左上角？
在content_main.xml中拖放完全没有问题，我尝试将按钮xml代码从content_main.xml复制到activity_main.xml，但按钮仍然位于左上角
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout 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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/Theme.MyApplication.AppBarOverlay">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/Theme.MyApplication.PopupOverlay" />
</com.google.android.material.appbar.AppBarLayout>
<include layout="@layout/content_main" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_marginEnd="@dimen/fab_margin"
android:layout_marginBottom="16dp"
app:srcCompat="@android:drawable/ic_dialog_email" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
1条答案
按热度按时间r7s23pms1#
The layout of elements in design are composed of three main designs. You have Linear Layout, Relative Layout and Constraint Layout.
Constraint Layout
Constraint uses anchor points. You have to anchor them to parent or other elements. So if you wanted two buttons side by side. You would anchor them to parent or other elements or parent. Click on the element then attributes and select the position of the element.
Linear and Relative Latouts
These layouts are more of a stackable layout. They are stacked above or below the element before.
Personally I use constraint layout. But the reason why the element stays in the left corner is because that's the 0,0 point. So once you constrain the points to parent or other elements they will look good in design.
Now each person has their favorite layout. But sometimes you may have to call multiple layouts in a design so you may have all three in one design.
Take this for example
This was built in linear layout. It stacks on top of each other.
The next image is a Constraint layout
This is a series of constraint layouts where buttons are anchored together. You could build this in relative or linear but it gets a little more complex in my opinion.
I hope this helps with how designs are done with the different layouts.