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Switch between Gallery and a LinearLayout - ClassCastException

开发者 https://www.devze.com 2023-02-25 03:30 出处:网络
Thanks for reading! I am building a custom Gallery app where the first thumbnail is an album cover displaying album details.Here\'s the flow:

Thanks for reading!

I am building a custom Gallery app where the first thumbnail is an album cover displaying album details. Here's the flow:


getView() {
//inflate cover.xml which includes two textviews and an imageview.
    if(position == 0)
         //set some album-specific text
    else 
         //set image-specific text
}

Here's the actual getView() code:


 public View getView(int position, View convertView, ViewGroup parent) {
            //TODO: Recycle view
            convertView = mInflater.inflate(R.layout.cover, null);
            TextView tvTxt1 = (TextView)convertView.findViewById(R.cover.tvCoverText1);
            TextView tvTxt2 = (TextView)convertView.findViewById(R.cover.tvCoverText2);
            //ImageView imgView = (ImageView)convertView.findViewById(R.cover.imgImage);

            if(position == 0) {
                tvTxt1.setText("AlbumText1");
                tvTxt2.setText("AlbumText2");
                return convertView;
            }
            else {
                tvTxt1.setText("ImageText1"); 
                tvTxt2.setText("ImageText2");
                ImageView imgView = new ImageView(mContext);
                imgView.setImageResource(mImageIds[position]);
       开发者_运维技巧         imgView.setLayoutParams(new Gallery.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
                imgView.setScaleType(ImageView.ScaleType.FIT_XY);
                imgView.setBackgroundResource(mGalleryItemBackground);
                return imgView;
                //return convertView;
            }
        }

The cover.xml contains an ImageView and two TextViews.

when I return convertView in the else block, I get a ClassCastException. I am certainly doing something wrong.

I have spent almost two days on this now :(

Please help!


Here's what it looks like to me. When position == 0 you are returning convertView, which is a View. When you return "else", you are returning a ImageView. Your method is set to return a View. Try casting your ImageView to a View before returning it.

Try: return (View) imgView;

Never tried it myself though...


Add this imageview into your layout xml, and then retrieve it from convertview and at the end return the convert view. This may solve the problem. I have worked a lot on Gallery widget, if there is more problem do let me know.


After trying all the suggestions given by helpful people here,I still wasn't able to get across the ClassCastException.

So, as a workaround - I sort of "overlayed" the Gallery with other views that I wanted to enable/disable.

This is a workaround, so if someone comes up with a better answer - do post it here so I can accept it.

So here's what worked for me:

public View getView(int position, View convertView, ViewGroup parent) {
            //TODO: Recycle view
            //onvertView = mInflater.inflate(R.layout.cover, null);
            //ImageView imgView = (ImageView)convertView.findViewById(R.cover.imgImage);
            ImageView imgView = new ImageView(mContext);
            imgView.setImageResource(mImageIds[position]);
            imgView.setLayoutParams(new Gallery.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
            imgView.setScaleType(ImageView.ScaleType.FIT_XY);
            imgView.setBackgroundResource(mGalleryItemBackground);

            if(position == 0) {
                tvText1.setText("AlbumText1");
                tvText2.setText("AlbumText2");
                tvText3.setVisibility(View.VISIBLE);
                bottomBar.setVisibility(View.VISIBLE);
            }
            else {
                tvText1.setText("ImageText1"); 
                tvText2.setText("ImageText2");
                tvText3.setVisibility(View.GONE);
                bottomBar.setVisibility(View.GONE);
            }
            return imgView;
        }

Here's my layout main.xml file:


<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent">
    <Gallery android:id="@+main/gallery" android:layout_width="fill_parent"
        android:layout_height="fill_parent" />
    <!-- <ImageView android:id="@+main/imgImage" -->
    <!-- android:layout_width="fill_parent" android:layout_height="fill_parent" -->
    <!-- android:adjustViewBounds="true"> -->
    <!-- </ImageView> -->
    <TextView android:id="@+main/tvText2" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:singleLine="true"
        android:maxLines="1" android:text="Text2"
        android:layout_alignParentBottom="true" />
    <TextView android:id="@+main/tvText1" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:maxLines="2"
        android:text="Text1" android:layout_above="@main/tvText2" />
        <RelativeLayout android:id="@+main/bottomBar" android:layout_alignParentBottom="true"
            android:layout_width="fill_parent" android:layout_height="40dip"
            android:background="#A3A1A1">
            <TextView android:id="@+main/tvBottomText" android:layout_height="wrap_content" android:layout_width="fill_parent" 
                android:text="BottomBarText"/>
        </RelativeLayout>
</RelativeLayout>

The rest of the code in Main.java (whose getView method I modified) is almost verbatim from here

Thanks again for helping out!

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