How to implement zoom effect for image view in android?

I hope you are doing well.it often happens with all when they want to add new functionality in your app then normally they all search for libraries which are not good tactic because you don`t know what kind of code is in that libabry. so I always prefer to fork the libraries and add the useful classes and methods in my application code.

so when I stuck with the same issue, I make lots of much R&D then I find a class which gives the ability to zoomIn ,zoomOut and pinIn and out. so you can see that class here..

so as I told before, it is a single class. so you can put this class anywhere in your projects like utils folder.and put below lines into your XML files like:

<your_packege_name.TouchImageView
        android:id="@+id/frag_imageview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="fitCenter"
        android:src="@drawable/default_flag"
        android:transitionName="@string/transition_name_phone" /> 

and you can find that image view in your respected activity, as you did for all views like -:

TouchImageView tv=(TouchImageView)findViewById(R.id.frag_imageview); 
tv.setImageResource(R.drawable.ic_play);

that's it for TouchImageView. enjoy our code :)

Very simple way (Tested) :-

PhotoViewAttacher pAttacher;
pAttacher = new PhotoViewAttacher(Your_Image_View);
pAttacher.update();

Add bellow line in build.gradle :-

compile 'com.commit451:PhotoView:1.2.4'

Lazy man can use this lib, Just import inside your project and

ImageView mImageView;
PhotoViewAttacher mAttacher;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Any implementation of ImageView can be used!
    mImageView = (ImageView) findViewById(R.id.iv_photo);

    // Set the Drawable displayed
    Drawable bitmap = getResources().getDrawable(R.drawable.wallpaper);
    mImageView.setImageDrawable(bitmap);

    // Attach a PhotoViewAttacher, which takes care of all of the zooming functionality.
    mAttacher = new PhotoViewAttacher(mImageView);
}


// If you later call mImageView.setImageDrawable/setImageBitmap/setImageResource/etc then you just need to call
mAttacher.update();

Here is one of the most efficient way, it works smoothly:

https://github.com/MikeOrtiz/TouchImageView

Place TouchImageView.java in your project. It can then be used the same as ImageView.

Example:

TouchImageView img = (TouchImageView) findViewById(R.id.img);

If you are using TouchImageView in xml, then you must provide the full package name, because it is a custom view.

Example:

    <com.example.touch.TouchImageView
            android:id="@+id/img”
            android:layout_width="match_parent"
            android:layout_height="match_parent" />