"IllegalStateException : scrollview can host only one direct child" in one LinearLayout adding

Question

I have list of attached files and want to make my LinearLayout with it be horizontally Scrollable. I add only one child LinearLayout to my HorizontalScrollView, besides I get IllegalStateException. My xml:

   <HorizontalScrollView
android:id="@+id/scrollMessageFiles"
android:layout_width="fill_parent"
android:layout_height="65dp"
android:layout_below="@+id/editMessage"
android:orientation="horizontal"
android:weightSum="1.0" >
        <LinearLayout
    android:id="@+id/panelMessageFiles"
    android:orientation="horizontal"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:background="#FFFFFF"
    >

        </LinearLayout>

        </HorizontalScrollView>

and want to add list of files to the LinearLayout in the ScrollView like this:

public void addFiles()
 {



    HorizontalScrollView scroll = (HorizontalScrollView) findViewById(R.id.scrollMessageFiles);
    LinearLayout layout = (LinearLayout) findViewById(R.id.panelMessageFiles);
    if(!FileManagerActivity.getFinalAttachFiles().isEmpty())
    {
             for (File file: FileManagerActivity.getFinalAttachFiles())
              {

                    View line = new View(this);

                    line.setLayoutParams(new LayoutParams(1, LayoutParams.MATCH_PARENT));
                    line.setBackgroundColor(0xAA345556);
                    informationView = new TextView(this);
                    informationView.setTextColor(Color.BLACK);
                    informationView.setTextSize(12);
                    informationView.setCompoundDrawablesWithIntrinsicBounds(
                            0, R.drawable.file_icon, 0, 0);
                    informationView.setText(file.getName().toString());
                    layout.addView(informationView, 0);
                    layout.addView(line, 1);


              }
             scroll.addView(layout);
      }

}

I add only one LinearLayout to the HorizontalScrollView, besides get

        FATAL EXCEPTION: main
     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.assignmentexpert/com.assignmentexpert.NewMessageActivity}: java.lang.IllegalStateException: HorizontalScrollView can host only one direct child
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:3687)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:507)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalStateException: HorizontalScrollView can host only one direct child
    at android.widget.HorizontalScrollView.addView(HorizontalScrollView.java:223)
    at com.assignmentexpert.NewMessageActivity.addFiles(NewMessageActivity.java:165)
    at com.assignmentexpert.NewMessageActivity.onCreate(NewMessageActivity.java:90)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)

at the line

 scroll.addView(layout);

Answer 1

You just need to remove this line: scroll.addView(layout); You already have this declared in xml and are trying to add it again, that's why you are getting the multiple children exception.

Try to run this:

public void addFiles() {
    HorizontalScrollView scroll = (HorizontalScrollView) findViewById(R.id.scrollMessageFiles);
    LinearLayout layout = (LinearLayout) findViewById(R.id.panelMessageFiles);
    if(!FileManagerActivity.getFinalAttachFiles().isEmpty()) {
        for (File file: FileManagerActivity.getFinalAttachFiles()) {

            View line = new View(this);

            line.setLayoutParams(new LayoutParams(1, LayoutParams.MATCH_PARENT));
            line.setBackgroundColor(0xAA345556);
            informationView = new TextView(this);
            informationView.setTextColor(Color.BLACK);
            informationView.setTextSize(12);
            informationView.setCompoundDrawablesWithIntrinsicBounds(
                    0, R.drawable.file_icon, 0, 0);
            informationView.setText(file.getName().toString());
            layout.addView(informationView, 0);
            layout.addView(line, 1);

        }
        // This line is telling the system to add your LinearLayout to the ScrollView when it is already there, declared in your xml layout file
        //scroll.addView(layout);
    }

}