This article shows how you can do simple image scaling in Android.
Here I have a simple class that Scales the image.
The Utility class
package pinch_zoom_demo.coderzheaven.com.pinchtozoomdemo;import android.view.ScaleGestureDetector;import android.widget.ImageView;import android.widget.TextView;public class ImageScaler extends ScaleGestureDetector.SimpleOnScaleGestureListener { TextView scaleDataMsg; ImageView myImage; float factor; public ImageScaler(TextView v, ImageView iv) { super(); scaleDataMsg = v; myImage = iv; } @Override public boolean onScaleBegin(ScaleGestureDetector detector) { factor = 1.0f; return true; } @Override public boolean onScale(ScaleGestureDetector detector) { float scaleFactor = detector.getScaleFactor() - 1; factor += scaleFactor; scaleDataMsg.setText(String.valueOf(scaleFactor) + "\n" + String.valueOf(factor)); myImage.setScaleX(factor); myImage.setScaleY(factor); return true; }} |
Layout
The layout which shows the image for scaling.
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp"> <TextView android:id="@+id/scaleDataMsg" android:layout_width="match_parent" android:layout_height="wrap_content" /> <ImageView android:id="@+id/myImage" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/android" /></LinearLayout> |
Set the above xml as layout for the Activity.
Activity
package pinch_zoom_demo.coderzheaven.com.pinchtozoomdemo;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.MotionEvent;import android.view.ScaleGestureDetector;import android.widget.ImageView;import android.widget.TextView;public class MainActivity extends AppCompatActivity { private TextView scaleDataMsg; private ImageView myImage; private ScaleGestureDetector scaleGestureDetector; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); scaleDataMsg = (TextView) findViewById(R.id.scaleDataMsg); myImage = (ImageView) findViewById(R.id.myImage); scaleGestureDetector = new ScaleGestureDetector( this, new ImageScaler(scaleDataMsg, myImage)); } @Override public boolean onTouchEvent(MotionEvent event) { scaleGestureDetector.onTouchEvent(event); return true; }} |
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