How to achieve multitouch for whole activity?

Question

I have one activity which is having linear layout and inside this layout there are several linear layouts and each linear layout is having set if buttons and text views. I want to achieve multi touch feature for whole screen means if user perform zoom in-zoom out using his finger then it should zoom in and zoom out whole screen(increase and decrease all buttons,text views size accordingly once).

How to achieve it using android 2.1?

regards, Piks

have you solved the problem . . . . i need the same solution . . .plz help me — Nirmal Prajapat, Mar 06 '18 at 05:07

score 0 · Accepted Answer · answered Jun 08 '12 at 10:05

This might give you an idea:

import java.util.ArrayList;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.DashPathEffect;
import android.graphics.Paint;
import android.graphics.PointF;
import android.util.AttributeSet;
//import android.util.FloatMath;
import android.view.MotionEvent;
import android.view.View;

public class MultitouchView extends View {
    private static final int STROKE_WIDTH = 1;
    private static final int CIRCLE_RADIUS = 20;

    private ArrayList<PointF> touchPoints = null;
    private Paint drawingPaint = null;
    private boolean isMultiTouch = false;
    private int pathEffectPhase = 0;

    public MultitouchView(Context context) {
        super(context);

        initialize(context);
    }

    public MultitouchView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        initialize(context);
    }

    public MultitouchView(Context context, AttributeSet attrs) {
        super(context, attrs);

        initialize(context);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if(touchPoints.size() > 0)
        {
            DashPathEffect effect = new DashPathEffect(new float[] {7,7}, pathEffectPhase);
            PointF midpt = null;

            drawingPaint.setPathEffect(effect);

            for(int index=1; index<touchPoints.size(); ++index)
            {
                midpt = getMidPoint(
                        touchPoints.get(index - 1).x,touchPoints.get(index - 1).y,
                        touchPoints.get(index).x,touchPoints.get(index).y);

                canvas.drawCircle(
                        touchPoints.get(index - 1).x,touchPoints.get(index - 1).y, 
                        1, drawingPaint);
                canvas.drawCircle(
                        touchPoints.get(index - 1).x,touchPoints.get(index - 1).y, 
                        CIRCLE_RADIUS, drawingPaint);

                canvas.drawCircle(touchPoints.get(index).x,touchPoints.get(index).y, 
                        1, drawingPaint);
                canvas.drawCircle(touchPoints.get(index).x,touchPoints.get(index).y, 
                        CIRCLE_RADIUS, drawingPaint);

                canvas.drawLine(
                        touchPoints.get(index - 1).x,touchPoints.get(index - 1).y,
                        touchPoints.get(index).x,touchPoints.get(index).y,
                        drawingPaint);

                canvas.drawCircle(midpt.x,midpt.y, 10, drawingPaint);
            }

            ++pathEffectPhase;

            invalidate();
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        super.onTouchEvent(event);

        int action = event.getAction() & MotionEvent.ACTION_MASK;

        switch(action)
        {
            case MotionEvent.ACTION_DOWN:
            {
                invalidate();

                break;
            }
            case MotionEvent.ACTION_POINTER_DOWN:
            {
                isMultiTouch = true;

                setPoints(event);
                invalidate();

                break;
            }
            case MotionEvent.ACTION_POINTER_UP:
            {
                isMultiTouch = false;

                break;
            }
            case MotionEvent.ACTION_MOVE:
            {
                if(isMultiTouch)
                {
                    setPoints(event);
                    invalidate();
                }

                break;
            }
        }

        return true;
    }   

    private void initialize(Context context){
        drawingPaint = new Paint();

        drawingPaint.setColor(Color.RED);
        drawingPaint.setStrokeWidth(STROKE_WIDTH);
        drawingPaint.setStyle(Paint.Style.STROKE);
        drawingPaint.setAntiAlias(true);

        touchPoints = new ArrayList<PointF>();
    }

    public void setPoints(MotionEvent event){
        touchPoints.clear();

        int pointerIndex = 0;

        for(int index=0; index<event.getPointerCount(); ++index)
        {
            pointerIndex = event.getPointerId(index);

            touchPoints.add(new PointF(event.getX(pointerIndex),event.getY(pointerIndex)));
        }
    }

    private PointF getMidPoint(float x1,float y1, float x2, float y2) {
        PointF point = new PointF();

        float x = x1 + x2;
        float y = y1 + y2;

        point.set(x / 2, y / 2);

        return point;
    }
}

Could you please brief how the above code will help me to achieve my scenario where whole screen has to be resized once user perform touch operations on the screen.if the above code is applicable for my scenario then how can i enable it for my activity's parent linear layout so multitouch will be applicable for all components inside the layout means if i want to use this class in my activity to support multitouch then how to use it inside my activity? — piks, Jun 08 '12 at 10:18
Check out this blog post and the comments below: http://myandroidnote.blogspot.com/2011/03/zooming-view-completely.html — reuf, Jun 08 '12 at 10:27
Thanks for helping me out...link which you have shared to me is having proper scenario which i am looking for but it will work from api level 11 it seems and i am using API level 7 :(, so if you are having any other way to achieve it then pls share with me. — piks, Jun 08 '12 at 11:30
not working. i just want to zoom my activity on multi touch like in pdf reader. — AnAndroid, Jan 15 '14 at 06:14

How to achieve multitouch for whole activity?

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