MyImageView.java
package com.example.a09_45;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
public class MyImageView extends View {
private Drawable image;
private ScaleGestureDetector gestureDetector;
private float scale = 1.0f;
public MyImageView(Context context) {
super(context);
image = context.getResources().getDrawable(R.drawable.window);
setFocusable(true);
image.setBounds(0, 0, image.getIntrinsicWidth(), image.getIntrinsicHeight());
gestureDetector = new ScaleGestureDetector(context, new ScaleListener());
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.save();
canvas.scale(scale, scale);
image.draw(canvas);
canvas.restore();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
gestureDetector.onTouchEvent(event);
invalidate();
return true;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScale(ScaleGestureDetector detector) {
scale *= detector.getScaleFactor();
if (scale < 0.1f)
scale = 0.1f;
if (scale > 10.0f)
scale = 10.0f;
invalidate();
return true;
}
}
}
MainActivity.java
package com.example.a09_45;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new MyImageView(this));
}
}