How to make view react on click

Question

I have created custom widget which inherits View.

<com.test.www.view.ElementView
    android:id="@+id/surface1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:focusable="true"
    android:focusableInTouchMode="true"
    android:layout_weight="1"

/

>

and

public class ElementView extends View {
    private final int width=100;
    private final int height=100;
    private Paint paint=null;
    private Canvas canvas=null;

    public ElementView(Context context) {
        super(context);
        paint = new Paint();
    }

    public ElementView(Context context, AttributeSet attr) {
        super(context, attr);
        paint = new Paint();
    }


    public ElementView(Context context, AttributeSet attr, int defaultStyles) {
        super(context, attr, defaultStyles);
        paint = new Paint();
    }

    @Override
    protected void onMeasure(int widthSpec, int heightSpec) {
        int measuredWidth = MeasureSpec.getSize(widthSpec);
        int measuredHeight = MeasureSpec.getSize(heightSpec);
        setMeasuredDimension(this.width,this.height);

    }

    @Override
    protected void onDraw(Canvas canvas) {
        this.canvas=canvas;
        // get the size of your control based on last call to onMeasure
        int height = getMeasuredHeight();
        int width = getMeasuredWidth();

        // Now create a paint brush to draw your widget

        paint.setColor(Color.GREEN);

        //define border
        this.canvas.drawLine(0, 0, 0, 99, paint);
        this.canvas.drawLine(0, 0, 99,0, paint);
        this.canvas.drawLine(99, 0, 99, 99, paint);
        this.canvas.drawLine(0, 99, 99,99, paint);

        //define cells
        this.canvas.drawLine(0,50,99,50,paint);
        this.canvas.drawLine(30,0,30,50,paint);

        //draw green rectangle
        this.canvas.drawRect(new Rect(0,0,50,50),paint);
        //draw some text
        paint.setTextSize(8);
        paint.setColor(Color.RED);
        String displayText = "test";


        Float textWidth = paint.measureText(displayText);

        int px = width / 2;
        int py = height / 2;
        this.canvas.drawText(displayText, px - textWidth / 2, py, paint);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        paint.setColor(Color.RED);
        //change color of first cell
        canvas.drawRect(new Rect(0,0,50,50),paint);
        return super.dispatchTouchEvent(event);
    }

}

Problem is that this ElementView doesn't react on click. I have override of dispatch event but it doesn't come in. Can anybody help me ? What to do to make this ElementView react on click ?

score 2 · Answer 1 · answered Apr 05 '11 at 20:58

2

I would probably do something like this:

ElementView ev = (ElementView)findViewById(R.id.surface1);
ev.setOnClickListener(evOnClick);

public OnClickListener evOnClick = new OnClickListener() {
  @Override
  public void onClick(View v, int arg1) {
    //DO ONCLICK STUFF
  }
};

I'm not sure if you can actually put the onClick inside the view definition like you are trying to, but Id like if someone could show me how.

answered Apr 05 '11 at 20:58

sgarman

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Thanks, it enters now but I cannot change color ! It pas through code but view stays the same. – Damir Apr 05 '11 at 21:28
Maybe in ElementView create a public function to handle color change. Then call that function in the onClick: ev.changeColor(someVar); – sgarman Apr 05 '11 at 21:31
You might try calling invalidate() on the view at the end of processing the onClick stuff, forcing it to redraw. – coder_tim Apr 05 '11 at 22:40

How to make view react on click

1 Answers1