ZoomImageView

A custom ImageView Implementation

Supports

• Double-tap to zoom
• Pinch zoom
• Drag to pan
• Fling to pan
• Swipe to dismiss

Implementation

Extends the standard AppCompatImageView api with a few minor additions

Add to layout

<com.k2.zoomimageview.ZoomImageView
    android:id="@+id/iv"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

Drawable callback

imageView.onDrawableLoaded {
    // invoked when any image is loaded, like from a library like Glide, picasso or coil
    // can be used for updating progress UI
}

Get/Set zoom level

imageView.currentZoom = 1.5F // sets current zoom to 1.5 x
imageView.currentZoom // returns 1.5F

Reset pan and zoom

imageView.resetZoom()

Parent layout touch intercept

Allow/disallow parent viewgroup to intercept touch event while zoomed in. Panning and swiping in a parent like ViewPager can cause some issues with gesture detection

imageView.disallowPagingWhenZoomed = true

Debug information

Display drawable bounds and scale/translate info on the view. Can be useful when modifying/debugging the view

imageView.debugInfoVisible = true

Swipe to dismiss

Enable/Disable

imageView.swipeToDismissEnabled = true

Dismiss callback. For best results use shared activity/fragment transition

imageView.onDismiss = {
    finishAfterTransition() or finish()
}

Track swipe to dismiss progress. Can be used to update UI accordingly

dismissProgressListener = { progress ->
    bgView.alpha = 1.0f - progress
}

Planned improvements and future additions

• Support for multiple scale types (only fit-center works for now)
• Publish as a library (maybe)

Credits

Huge thanks to Chris Banes for his PhotoView library

Casey Horner for this photo on unsplash

Coil lib

License and usage

Feel free to use this file in your code. Just download and add to your project