How to create Zoom Control with an image

Step 01: Make A Zoom Control With Image View MainActivity.xml

<LinearLayout android:orientation="vertical" android:gravity="center_horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content"> <ImageView android:id="@+id/ImageViewId" android:layout_gravity="center_horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_launcher" /> <ZoomControls android:layout_marginTop="200dp" android:id="@+id/ZoomControlId" android:layout_width="wrap_content" android:layout_height="wrap_content"></ZoomControls> </LinearLayout>

Step 02: Write Some Java Code For Zoom Control MainActivity.Java
 
public class MainActivity extends AppCompatActivity { private ImageView imageView; private ZoomControls zoomControls; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); imageView= (ImageView) findViewById(R.id.ImageViewId); zoomControls = (ZoomControls) findViewById(R.id.ZoomControlId); zoomControls.setOnZoomInClickListener(new View.OnClickListener() { @Override public void onClick(View v) { float x= imageView.getScaleX(); float y=imageView.getScaleY(); imageView.setScaleX((float)x+1); imageView.setScaleY((float)y+1); } }); zoomControls.setOnZoomOutClickListener(new View.OnClickListener() { @Override public void onClick(View v) { float x= imageView.getScaleX(); float y=imageView.getScaleY(); imageView.setScaleX((float)x-1); imageView.setScaleY((float)y-1); } }); } } <teaxtarea>