在kotlin中使用xml <include/>标记时会崩溃
在kotlin中使用xml <include/>标记时会崩溃
提问于 2019-09-18 10:04:49
我正在用kotlin编写代码，并在我的layout.xml中使用，当我调用布局的一个子程序时，我的应用程序崩溃了。
我父母的布局：
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
...
<include layout="@layout/bottomsheet_map" />
...
</androidx.constraintlayout.widget.ConstraintLayout>和bottomsheet_map.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/bottomsheet_map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/bg_app"
android:elevation="@dimen/medium"
android:fadingEdgeLength="@dimen/xLarge"
android:orientation="vertical"
app:behavior_peekHeight="50dp"
app:layout_behavior="com.idmpGroup.rtour.utilities.UI.AnchorSheetBehavior">
<RelativeLayout
android:id="@+id/tap_action_layout"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="@android:color/white"
android:elevation="@dimen/xSmall"
android:fadingEdgeLength="@dimen/standard"
android:gravity="center"
android:paddingStart="@dimen/standard"
android:paddingTop="@dimen/medium"
android:paddingEnd="@dimen/standard"
android:paddingBottom="@dimen/medium">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<View
android:layout_width="@dimen/xLarge"
android:layout_height="@dimen/xSmall"
android:layout_gravity="center"
android:background="@drawable/dr_btn_radius_solid2" />
<TextView
android:id="@+id/bottom_sheet_title"
style="@style/tvToolbar_style"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/medium"
android:gravity="center"
android:text="@string/show_list"
android:textColor="#979797" />
</LinearLayout>
</RelativeLayout>
</LinearLayout>当我想将OnClickListener设置为tap_action_layout in onCreateView时，我会崩溃
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val view = inflater.inflate(R.layout.layout, container, false)
tap_action_layout.setOnClickListener { v: View? ->
//....
}
return view
}tap_action_layout备注：I不会使用findViewByID .is --更好的解决方案--调用没有findViewByID()？的。
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.RelativeLayout.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.idmpGroup.rtour.fragments.BAS.NearlyFrag.onCreateView(NearlyFrag.kt:258)
at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2600)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:881)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824)
at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)
at androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java:150)
at android.os.Handler.handleCallback(Handler.java:907)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:216)
at android.app.ActivityThread.main(ActivityThread.java:7625)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987)回答 5
Stack Overflow用户
回答已采纳
发布于 2019-09-18 10:09:04
在onViewCreated而不是onCreateView中尝试这个
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
tap_action_layout.setOnClickListener { v: View? ->
//....
}
}Stack Overflow用户
发布于 2019-09-18 10:24:17
您不能直接访问code.You中包含的元素，需要在包含其他布局的父布局上使用findviewbyid。
例如：
<include layout="@layout/bottomsheet_map" android:id="@+id/include_layout" />
val tap_action_layout = include_layout.findViewById(R.id.tap_action_layout)
tap_action_layout.setOnClickListener { v: View? ->
//....
}Stack Overflow用户
发布于 2019-09-18 10:25:54
您必须首先在xml布局中将android:id设置为include标记：
<include android:id="@+id/my_layout"
layout="@layout/bottomsheet_map" />在您设置id之后，您需要首先调用id from include布局标记，以获得不可空的tap_action_layout，并且您应该从片段中的onViewCreated方法调用它：(请注意，只有在使用kotlinx.android.synthetic处理绑定视图时才能这样做)
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
my_layout.top_action_layout.setOnClickListener {
// do whatever you wanna do here..
}
}否则，如果您不使用kotlin人工合成，您需要首先调用findViewById(R.id.top_action_layout)：
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
my_layout.findViewById(R.id.top_action_layout).setOnClickListener {
// do whatever you wanna do here..
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/57990167
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