[英]How to add a TextView to a ScrollView
我試圖將(未知)數量的消息呈現到可滾動列表中。 我正在創建一個TextView
,將消息作為文本以及與消息相關的URL作為onclick
動作,但是我無法在視圖中呈現TextView
。
我試圖添加textView
使用.addView
方法,得到了后scrollView
ID。 這不起作用,因為即使找到了id, scrollView
仍然為null
。
我的renderMessage
方法從onClick
事件獲取傳遞的視圖,該事件存儲在View view
。
mainactivity的xml代碼為:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:background="#2196F3"
android:forceDarkAllowed="false"
android:gravity="center_horizontal|center_vertical"
android:paddingTop="20dp"
android:paddingBottom="20dp"
android:text="@string/headerTitle"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:textColor="#FFFFFF"
android:textSize="24sp"
android:textStyle="bold"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<Button
android:id="@+id/logTokenButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:text="@string/msgTokenButton"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent" />
<ScrollView
android:id="@+id/messageInsertionPoint"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toTopOf="@+id/logTokenButton"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView3"
app:layout_constraintVertical_bias="0.239">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" />
</ScrollView>
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:onClick="syncMessages"
android:text="@string/sync_messages_button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toEndOf="@+id/logTokenButton"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
</androidx.constraintlayout.widget.ConstraintLayout>
TextView textView = new TextView(applicationContext);
textView.setText(msg.getMessage());
if (msg.getLink() != null) {
final pushMessage finalMsg = msg;
textView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse(finalMsg.getLink()));
applicationContext.startActivity(intent);
}
});
}
ScrollView scrollView = view.findViewById(R.id.messageInsertionPoint);
scrollView.addView(textView, 0, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
}
我得到的錯誤代碼是:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.mypackage.notifications, PID: 10449
java.lang.IllegalStateException: Could not execute method for android:onClick
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ScrollView.addView(android.view.View, int, android.view.ViewGroup$LayoutParams)' on a null object reference
at com.myclass.notifications.messageManipulation.renderMessages(messageManipulation.java:54)
at com.myclass.notifications.MainActivity.syncMessages(MainActivity.java:41)
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
ScrollView
為null,很可能是您引用了錯誤的android:id
視圖。 或視圖處於其他布局或類似內容
編輯 :ScrollView只能有一個孩子。 說一個LinearLayout
。 然后,您可以動態地向該LinearLayout
添加其他視圖。
LinearLayout summary = findViewById(R.id.linearLayout);
summary.addView(age_table_populate());
View age_table = LayoutInflater.from(ResultActivity.this).inflate(R.layout.age_table,null,false);
TextView input=(TextView)age_table.findViewById(R.id.title);
String age_table_label = "label";
input.setText(age_table_label);
summary.addView(age_table);
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.