How to use pinch zoom with scrollview?

Question

I am writing a code for pinch zoom for textview . Since I am using soo many textviews . I have to use scrollview. If I use scrollview pinch zoom is not working . Otherwise my code is working fine without scrollview. Is there any method to use pinch zoom along with scrollview

score 1 · Answer 1 · edited May 23 '17 at 11:56

1

You can create an AlertDialog, with a custom view (which can have whatever you want in it).

Here is one (of many) links on how to do this: How to implement a custom AlertDialog View

edited May 23 '17 at 11:56

Community

1
1

answered Feb 16 '15 at 14:04

Booger

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Thank you ! i want to popup exactly like this link http://ajaxian.com/archives/tooltip.jpg – Satz Napster Feb 16 '15 at 14:09
please guide me. it is possible in android – Satz Napster Feb 16 '15 at 14:10
@SatzNapster Yes it is possible with the solution provided by Booger. But no one will give you the exact layout here. Code it for yourself and ask any specific details you want help with. – VipulKumar Feb 16 '15 at 14:24

score 0 · Answer 2 · answered Feb 24 '22 at 13:12

To have a ScrollView with pinch to zoom TextView, you have to capture the touch events on the ScrollView and assign the pinch zoom if 2 fingers are detected like so.

Java class

import android.os.Bundle;
import android.util.Log;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.widget.NestedScrollView;

public class MyExampleClass extends AppCompatActivity {

    private NestedScrollView myScrollView;
    private TextView myTextView;
    private ScaleGestureDetector scaleGestureDetector;
    private ArrayList<TextView> textViews = new ArrayList<TextView>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_example_xml);

        /* instantiation */

        myTextView = findViewById(R.id.ourTextView1);
        myScrollView = findViewById(R.id.ourScrollview);
        scaleGestureDetector = new ScaleGestureDetector(this, new simpleOnScaleGestureListener());

        /* set a custom onTouchListener to the scrollview */

        myScrollView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View view, MotionEvent event) {

                /* if 2 fingers are touching the screen, start text resizing */

                if (event.getPointerCount() > 1) {
                    myScrollView.requestDisallowInterceptTouchEvent(true);
                    scaleGestureDetector.onTouchEvent(event);
                    return true;
                }

                /* otherwise pass the touch event to the scrollView for scrolling */

                return false;
            }
        });

    /* add all out TextViews to an ArrayList */

    textViews.add(findViewById(R.id.ourTextView1));
    textViews.add(findViewById(R.id.ourTextView2));
    }

    /* inner class for handling pinch zoom */

    public class simpleOnScaleGestureListener extends
            ScaleGestureDetector.SimpleOnScaleGestureListener {

        @Override
        public boolean onScale(ScaleGestureDetector detector) {

            /* get current text size */

            float size = myTextView.getTextSize();
            Log.d("TextSizeStart", String.valueOf(size));

            /* get how much user pinched */

            float factor = detector.getScaleFactor();
            Log.d("Factor", String.valueOf(factor));

            /* calculate how much to resize to */

            float product = size * factor;
            Log.d("TextSize", String.valueOf(product));

            /* set max size. if product equals more than 140, set product to 140 */

            if (product > 140) {
                product = 140;
            }

            /* set min size. if product equals less than 60, set product to 60 */

            if (product < 60) {
                product = 60;
            }

            /* set textSize in all textViews in arraylist to new size */

            for (TextView v: textViews) {
                v.setTextSize(TypedValue.COMPLEX_UNIT_PX, product);
            }

            /* set size to new textSize */

            size = myTextView.getTextSize();
            Log.d("TextSizeEnd", String.valueOf(size));
            return true;
        }
    }
}

xml file

<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/ourScrollview"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MyExampleClass">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

    <TextView
        android:id="@+id/ourTextView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="11dp"
        android:textSize="30sp"
        android:text="@string/long_text" />

    <TextView
        android:id="@+id/ourTextView2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="11dp"
        android:textSize="30sp"
        android:text="@string/long_text" />

    </LinearLayout>

</androidx.core.widget.NestedScrollView>

How to use pinch zoom with scrollview?

2 Answers2