android - Pinch zooming, textview

Question

I'm trying to create an app which displays lyrics for the user. The lyrics are stored within values/strings.xml and displayed for the user when accessing the activity. (I'm not sure if this is a good way of doing it).

Depending on how long each line of text is I dont know which textsize I should use and I would really be able to use some "pinch to zoom" function.

However, I dont know if it is possible "pinch" to zoom on textviews. Ive found various methods of doing it on webviews and imageviews but none for textviews.

I'm looking for the best way of increasing textsize/zooming the layout by "pinch"

Help with how to store the strings and displaying is very welcome as well.

Cheers!

Answer 1

I am new to Android development and have tried to figure out the same. I have test application working with pinch zoom but with the issue asked at https://stackoverflow.com/questions/14306908/textview-in-a-scrollview-with-pinch-zoom

This is however working

package com.example.pinchzoom;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.util.TypedValue;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.ScaleGestureDetector.SimpleOnScaleGestureListener;
import android.widget.TextView;

public class MainActivity extends Activity {

    TextView scaleGesture;
    ScaleGestureDetector scaleGestureDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        scaleGesture = (TextView)findViewById(R.id.article);
        scaleGesture.setText("this is some text");
        scaleGestureDetector = new ScaleGestureDetector(this, new simpleOnScaleGestureListener());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }


    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        scaleGestureDetector.onTouchEvent(event);
        return true;
    }

    public class simpleOnScaleGestureListener extends
            SimpleOnScaleGestureListener {

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            // TODO Auto-generated method stub
            float size = scaleGesture.getTextSize();
            Log.d("TextSizeStart", String.valueOf(size));

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


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

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

The view

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >
    <TextView
        android:id="@+id/article"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</RelativeLayout>