Click event of HorizontalScrollView

Question

I have a horizontalscrollview inside which i have a bunch of images. Now i need to detect the click event in case any of the image is clicked within it. In short, i need the index of the image placed inside the horizontalscrollview, which was clicked.

<HorizontalScrollView
    android:id="@+id/horizontalScrollView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/bgcolor" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/imageview1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:paddingRight="20dp"
            android:src="@drawable/image1" />

       <ImageView
            android:id="@+id/imageview2"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:paddingRight="20dp"
            android:src="@drawable/image2" />

I tried playing around OnTouchListener event, but that was getting triggered even while scrolling. And the OnClickListener was not even getting triggered no matter wherever you click.

horizontalScrollView1.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            System.out.println("Testing scrollview");
        }
    });

Is there a workaround to get the index of the clicked image present inside the horizontalscrollview? I guess it can be achieved via "Gallery" widget but that is deprecated in API16. Can anyone share an approach to accomplish this via HorizontalScrollView?

Answer 1

Attach an OnClickListener to each of the ImageView widgets in the HorizontalScrollView. Based on the View passed into onClick(), you will know which ImageView was clicked.

Specifically:

• Add android:onClick="heyMyImageGotClickedWhoHoo" to each ImageView element in your layout.

• Implement a public void heyMyImageGotClickedWhoHoo(View v) method in the activity that is loading this layout. In the body, you can use v.getId() and compare it to the ImageView widget IDs (e.g., R.id.imageview1) to determine which got clicked.

Or, you can create dedicated methods for each ImageView, rather than route them all to one. In that case, each android:onClick attribute would have a different value (e.g., omgTheFirstImageWasClicked), with a matching method in the activity (e.g., public void omgTheFirstImageWasClicked(View v)).

Answer 2

I assume the number of ImageViews may vary in your case. Then I would suggest using a List of IDs to keep record of them. While inserting new ImageView to HorizontalScrollView, use setId method to add each ImageView a custom ID and then add this ID to your List.

int uniqueID = getNewID();
myImage.setId(uniqueID);
myIdList.add(uniqueID);
myScrollView.addView(myImage);

If the number of ImageViews is fixed, then you can of course use classic array:

int[] ids = {R.id.firstImage, R.id.secondImage};

Then your onClick method (you have to add it to each ImageView) will look like this:

public void onClick(View v) {
    for(int i=0; i<ids.size(); i++) {
        if(v.getId() == ids.get(i)) {
            Toast.makeText(this, "Index "+(i+1), Toast.LENGTH_SHORT).show();
        }
    }
}

EDIT: how to create valid IDs - Android: View.setID(int id) programmatically - how to avoid ID conflicts?