How To Allow User To Drag And Drop An Image Within A Linearlayout

I have a LinearLayout set up which has an image within it. My XML layout:

Solution 1:

Here is a colorpicker widget for your site. I dont know if this is exactly what your looking for but I definetly hope it helps!

<divstyle="font-family:Arial,Helvetica,sans-serif;border:solid 1px 
#cccccc;position:absolute;width:240px;height:326px;background: #ffffff;-moz-box-shadow:0 0 
6px rgba(0,0,0,.25);-webkit-box-shadow: 0 0 6px rgba(0,0,0,.25);box-shadow:0 0 6px 
rgba(0,0,0,.25);-moz-border-radius: 5px;-webkit-border-radius:5px;border-radius:5px;"><divstyle="background-color:#2d6ab4;position:absolute;top:0px;left:0px; width:100%; 
height:22px;text-align:center;padding-top:2px;font-weight:bold;border-top-right-
radius:5px;border-top-left-radius:5px;"><astyle="text-decoration:none;color:#ffffff;"target="_blank"href="">Color Picker</a></div><scriptsrc="http://widget.colorcodehex.com/color-picker/abcdef.html"type="text/javascript"></script></div>

Solution 2:

How can I allow the user to drag and drop the small square image within the layout ONLY and also retrieve the X and Y values?

• Check out this tutorial for an idea on drag and drop of a ui element

Whenever, the user presses inside the layout, the square moves to that coordinate within the layout. How can I do that?

• Furthermore from the tutorial, llColorSpect can also implement a MotionEvent.ACTION_DOWN event to move ivSquare to the x,y of the MotionEvent

I want to then use those X and Y values to get the HEX/RGB values. How would I be able to accomplish it?

• This is going to be more tricky. You will require some lookup that translates the x,y values into the HEX or RGB values. You can get View.getMeasuredWidth() and View.getMeasuredHeight() of llColorSpect to find out the dimensions that it appears on screen. Say for example the width of the spectrum range is from 0-1000 and llColorSpect's measured distance is from 0-3000, user clicks 300, then you'll know that spectrumLookup(300/3) == 100 so you'd use the spectrum color @ 100.

Good luck!

Solution 3:

I suggest using a Canvas for your image as this would allow you to draw the square to select the colour over the colour spectrum.

The code below uses a canvas that overrides onTouchEvent and will give you be able to give you the coordinates of where the user presses.

publicclassCanvasViewextendsView {

    private Bitmap bitmap;
    private Bitmap square;
    privatefloatmScaleFactor=1f;
    intx=0;
    inty=0;

    publicCanvasView(Context c) {
        super(c);
        bitmap= BitmapFactory.decodeResource(c.getResources(), R.drawable.colour);
        square = BitmapFactory.decodeResource(c.getResources(), R.drawable.square);
    }

    @OverrideprotectedvoidonSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
    }

    @OverrideprotectedvoidonDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.scale(mScaleFactor, mScaleFactor);
        canvas.drawBitmap(bitmap, 0, 0, null);
        canvas.drawBitmap(square, x, y, null);
    }

    @OverridepublicbooleanonTouchEvent(MotionEvent event) {

        floatx= event.getX();
        floaty= event.getY();
        Log.d("x and y", "X: " + x + " Y: " + y);
        intpixel= bitmap.getPixel((int)x,(int) y);
        intredValue= Color.red(pixel);
        intblueValue= Color.blue(pixel);
        intgreenValue= Color.green(pixel);
        Log.d("Colours","R:" +redValue +" B:" + blueValue + " G:" +greenValue);

        //Draw onto the square onto imagethis.x = (int) x;
        this.y = (int) y;
        invalidate();


        returntrue;
    }

}

To use this CanvasView class simply do this or edit it for your own layouts:

CanvasViewcanvasView=newCanvasView(this);
    LinearLayoutlinearlayout= (LinearLayout) findViewById(R.id.linearlayout);
    linearlayout.addView(canvasView);

Finally the function to map the x and y to a colour. Simply read the pixel colour of the coordinates.

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