The Zoomcontrols control is a scalable control that enables two buttons to control the size of a picture

<?XML version= "1.0" encoding= "Utf-8"?><LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"android:orientation= "vertical"Android:layout_width= "Fill_parent"Android:layout_height= "Fill_parent"Android:id= "@+id/layout"    >    <ImageViewAndroid:id= "@+id/image"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"android:src= "@drawable/foot"        />    <ZoomcontrolsAndroid:id= "@+id/zoomcontrol"android:layout_gravity= "Bottom"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"        /></LinearLayout>

 Packagecom.example.yanlei.my;ImportAndroid.os.Bundle;Importandroid.support.v7.app.AppCompatActivity;ImportAndroid.view.Menu;ImportAndroid.view.MenuItem;ImportAndroid.os.Bundle;Importandroid.app.Activity;ImportAndroid.widget.Toast;ImportAndroid.view.Menu;ImportAndroid.view.MenuItem;Importandroid.app.Activity;ImportAndroid.graphics.Bitmap;Importandroid.graphics.BitmapFactory;ImportAndroid.graphics.Matrix;ImportAndroid.os.Bundle;ImportAndroid.util.DisplayMetrics;ImportAndroid.view.View;ImportAndroid.view.View.OnClickListener;ImportAndroid.widget.ImageView;Importandroid.widget.LinearLayout;ImportAndroid.widget.ZoomControls; Public classMainactivityextendsappcompatactivity {PrivateLinearLayout lllayout; PrivateZoomcontrols Zoomcontrols; PrivateImageView img; Private intID = 0; Private intDisplaywidth; Private intDisplayheight; Private floatScaleWidth = 1; Private floatScaleHeight = 1; PrivateBitmap Bitmap; @Override Public voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main); Lllayout=(LinearLayout) Findviewbyid (r.id.layout); //Get screen resolution sizeDisplaymetrics DM =NewDisplaymetrics ();        Getwindowmanager (). Getdefaultdisplay (). Getmetrics (DM); Displaywidth=Dm.widthpixels; //screen height minus the height of zoomcontrolsDisplayheight =Dm.heightpixels; Bitmap=Bitmapfactory.decoderesource (Getresources (), r.drawable.foot); IMG=(ImageView) Findviewbyid (r.id.image); //zoom.hide (); Hide Zoomcontrols//zoom.show (); Show ZoomcontrolsZoomcontrols=(Zoomcontrols) Findviewbyid (R.id.zoomcontrol); IMG=(ImageView) Findviewbyid (r.id.image); Zoomcontrols.setiszoominenabled (true); Zoomcontrols.setiszoomoutenabled (true); //image magnificationZoomcontrols.setonzoominclicklistener (NewOnclicklistener () { Public voidOnClick (View v) {intBmpwidth =bitmap.getwidth (); intBmpheight =bitmap.getheight (); //set picture to enlarge but scale                DoubleScale = 1.25; //calculate the ratio to enlarge this time.ScaleWidth = (float) (ScaleWidth *Scale ); ScaleHeight= (float) (ScaleHeight *Scale ); //produces a new size but bitmap objectMatrix Matrix =NewMatrix ();                Matrix.postscale (ScaleWidth, ScaleHeight); Bitmap resizebmp= Bitmap.createbitmap (Bitmap, 0, 0, bmpwidth, bmpheight, Matrix,true);            Img.setimagebitmap (resizebmp);        }        }); //Picture ReductionZoomcontrols.setonzoomoutclicklistener (NewOnclicklistener () { Public voidOnClick (View v) {intBmpwidth =bitmap.getwidth (); intBmpheight =bitmap.getheight (); //set picture to enlarge but scale                DoubleScale = 0.8; //calculate the ratio to enlarge this time.ScaleWidth = (float) (ScaleWidth *Scale ); ScaleHeight= (float) (ScaleHeight *Scale ); //produces a new size but bitmap objectMatrix Matrix =NewMatrix ();                Matrix.postscale (ScaleWidth, ScaleHeight); Bitmap resizebmp= Bitmap.createbitmap (Bitmap, 0, 0, bmpwidth, bmpheight, Matrix,true);            Img.setimagebitmap (resizebmp);    }        }); }}

Reference: http://blog.csdn.net/jianghuiquan/article/details/8350538

The Zoomcontrols control is a scalable control that enables two buttons to control the size of a picture