android中面向循环依赖的相对布局答案

【问题标题】：Relative Layout facing Circular Dependencies in androidandroid中面向循环依赖的相对布局
【发布时间】：2023-03-06 01:00:02
【问题描述】：

这是我的日志

05-12 01:51:47.855: E/AndroidRuntime(4707): java.lang.IllegalStateException: Circular dependencies cannot exist in RelativeLayout
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.RelativeLayout$DependencyGraph.getSortedViews(RelativeLayout.java:1691)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.RelativeLayout.sortChildren(RelativeLayout.java:373)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:381)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.View.measure(View.java:16497)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1226)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.ScrollView.onMeasure(ScrollView.java:326)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.View.measure(View.java:16497)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.View.measure(View.java:16497)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.View.measure(View.java:16497)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.View.measure(View.java:16497)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1916)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1113)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1295)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.Choreographer.doCallbacks(Choreographer.java:574)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.Choreographer.doFrame(Choreographer.java:544)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.os.Handler.handleCallback(Handler.java:733)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.os.Handler.dispatchMessage(Handler.java:95)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.os.Looper.loop(Looper.java:136)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at android.app.ActivityThread.main(ActivityThread.java:5017)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at java.lang.reflect.Method.invokeNative(Native Method)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at java.lang.reflect.Method.invoke(Method.java:515)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-12 01:51:47.855: E/AndroidRuntime(4707):     at dalvik.system.NativeStart.main(Native Method)

这是我的 activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Login" >

    <RelativeLayout
        android:id="@+id/RelativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TextView
            android:id="@+id/textViewLogin"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_above="@+id/passwordlogin"
            android:layout_centerHorizontal="true"
            android:text="@string/passwordlogin"
            android:textSize="20sp" />

        <EditText
            android:id="@+id/useridlogin"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignRight="@+id/passwordlogin"
            android:layout_below="@id/textViewLogin"
            android:ems="10"
            android:inputType="textEmailAddress" />

        <TextView
            android:id="@+id/textViewPassword"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_above="@+id/useridlogin"
            android:layout_below="@+id/imageView1"
            android:layout_centerHorizontal="true"
            android:text="@string/userid"
            android:textSize="20sp" />

        <EditText
            android:id="@+id/passwordlogin"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/textViewPassword"
            android:layout_centerHorizontal="true"
            android:ems="10"
            android:inputType="textPassword" >
        </EditText>

        <Button
            android:id="@+id/btnLogin"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:layout_alignLeft="@+id/registerlauncher"
            android:layout_below="@id/passwordlogin"
            android:layout_centerVertical="true"
            android:gravity="center"
            android:text="@string/button_login" />

        <TextView
            android:id="@+id/newuser"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/btnLogin"
            android:layout_centerHorizontal="true"
            android:text="@string/newuser" />

        <Button
            android:id="@+id/registerlauncher"
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:layout_alignRight="@+id/textViewLogin"
            android:layout_marginBottom="16dp"
            android:gravity="center"
            android:text="@string/button_register" />

        <ImageView
            android:id="@+id/imageView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_alignRight="@+id/useridlogin"
            android:layout_marginTop="50dp"
            android:contentDescription="@string/app_main"
            android:src="@drawable/pos_malaysia" />

    </RelativeLayout>
</ScrollView>

我想知道为什么我的其他 xml 文件工作正常，但是这个 activity_login.xml 无法在图形布局中显示。错误说渲染期间引发的异常：RelativeLayout 中不能存在循环依赖

【问题讨论】：

确保您的上/下控件不相互引用（control1 在 control2 之上，control2 在 control1 之下），另外，不要在引用中使用 @+id ，因为这会创建新的 id（并可能导致循环引用）。仅在定义新 ID 时使用 @+id
@DerGolem 我发现了上面/下面的关键字，并感谢您指出@+id。我忘了删除谢谢你的帮助
@DerGolem 尽管使用@id 不是问题，但不会创建新的 id（如果存在）
我以为@+id是用来创建id的，@id是用来引用的。
好的，我想我错过了这部分"The plus symbol, +, indicates that this is a new resource ID and the aapt tool will create a new resource integer in the R.java class, if it doesn't already exist."

标签： android xml circular-dependency

【解决方案1】：

试试这个....

<TextView
            android:id="@+id/textViewLogin"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
           android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:text="@string/passwordlogin"
            android:textSize="20sp" />

【讨论】：

它确实有助于解决问题，只是我不希望 textViewLogin 成为android:layout_alignParentTop="true"