我正在尝试以编程方式，当用户按下按钮时，将卡片视图添加到滚动视图。
但是，我意识到我遇到了这个错误
java.lang.IllegalStateException：ScrollView只能容纳一个直接子对象
我阅读了这篇文章How can I avoid "IllegalStateException: Scrollview can host only one direct child"?，并意识到我必须创建一个线性布局。
因此，我现在将cardview添加到linearlayout中，然后将该线性布局添加到scrollview中。但是我仍然遇到问题。
Error:
java.lang.IllegalStateException: ScrollView can host only one direct child
at android.widget.ScrollView.addView(ScrollView.java:233)
at com.app.appname.create.CreateCardViewProgrammatical
----------
----------
ly(create.java:97)
at com.app.supermarketaislefinder.create$1.onClick(create.java:52)
at android.view.View.performClick(View.java:4162)
at android.view.View$PerformClick.run(View.java:17082)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4867)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
at dalvik.system.NativeStart.main(Native Method)
line 97: `scrollView.addView(linearLayout);`
line 52 `CreateCardViewProgrammatically();`
create.java
public class create extends AppCompatActivity {
Button button;
Context context;
CardView cardview;
LayoutParams layoutparams;
TextView textview;
LinearLayout linearLayout;
ScrollView scrollView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.create);
button = (Button)findViewById(R.id.button);
context = getApplicationContext();
linearLayout = (LinearLayout) findViewById(R.id.linearlayout1);
scrollView = (ScrollView)findViewById(R.id.scrollView1);
//TODO FAB BUTTON
FloatingActionButton floatingActionButton =
(FloatingActionButton) findViewById(R.id.fab);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
CreateCardViewProgrammatically();
}
});
}
public void CreateCardViewProgrammatically(){
cardview = new CardView(context);
layoutparams = new LayoutParams(
LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT
);
cardview.setLayoutParams(layoutparams);
cardview.setRadius(15);
cardview.setPadding(25, 25, 25, 25);
cardview.setCardBackgroundColor(Color.MAGENTA);
cardview.setMaxCardElevation(30);
cardview.setMaxCardElevation(6);
textview = new TextView(context);
textview.setLayoutParams(layoutparams);
textview.setText("CardView Programmatically");
textview.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 25);
textview.setTextColor(Color.WHITE);
textview.setPadding(25,25,25,25);
textview.setGravity(Gravity.CENTER);
cardview.addView(textview);
linearLayout.addView(cardview);
scrollView.addView(linearLayout);
}
}
xml
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorBackground"
android:minHeight="170dp"
tools:context=".create"
tools:layout_editor_absoluteY="81dp"
>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/scrollView1"
android:layout_width="match_parent"
android:layout_height="438dp"
android:fillViewport="true"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="0dp">
<LinearLayout 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="com.android_examples.cardviewprogrammatically_android_examplescom.MainActivity"
android:id="@+id/linearlayout1">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click here to Create CardView programmatically on Button click"
android:id="@+id/button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</LinearLayout>
</ScrollView>
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="60dp"
android:layout_height="70dp"
android:layout_gravity="bottom|end"
android:layout_marginBottom="16dp"
android:layout_marginEnd="16dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="16dp"
android:layout_marginStart="8dp"
android:src="@android:drawable/ic_input_add"
app:backgroundTint="@color/colorCreate"
app:elevation="6dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:pressedTranslationZ="12dp"
android:tint="@color/colorBackground"/>
<View
android:id="@+id/subheading"
android:layout_width="match_parent"
android:layout_height="83dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="1dp"
android:layout_marginLeft="1dp"
android:layout_marginRight="1dp"
android:layout_marginStart="1dp"
android:layout_marginTop="2dp"
android:background="@color/colorBackground"
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"
/>
<View
android:id="@+id/view"
android:layout_width="320dp"
android:layout_height="1dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="76dp"
android:background="@color/colorText"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<View
android:id="@+id/view2"
android:layout_width="320dp"
android:layout_height="1dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="28dp"
android:background="@color/colorText"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="12dp"
android:text="@string/done_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/textView4"
app:layout_constraintTop_toBottomOf="@+id/view2" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="128dp"
android:layout_marginRight="128dp"
android:layout_marginTop="8dp"
android:text="@string/aisle_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="@+id/view"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@+id/view2"
app:layout_constraintVertical_bias="1.0" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_marginEnd="32dp"
android:layout_marginRight="32dp"
android:layout_marginTop="5dp"
android:text="@string/qty_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="@+id/view"
app:layout_constraintEnd_toStartOf="@+id/textView4"
app:layout_constraintTop_toBottomOf="@+id/view2"
app:layout_constraintVertical_bias="0.7" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="@string/item_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="@+id/view"
app:layout_constraintEnd_toStartOf="@+id/textView3"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/view2"
app:layout_constraintVertical_bias="1.0" />
</android.support.constraint.ConstraintLayout>