Is There an Example of How to Use a Touchdelegate in Android to Increase The Size of a View's Click Target

Is there an example of how to use a TouchDelegate in Android to increase the size of a view's click target?

I asked a friend at Google and they were able to help me figure out how to use TouchDelegate. Here's what we came up with:

final View parent = (View) delegate.getParent();
parent.post( new Runnable() {
    // Post in the parent's message queue to make sure the parent
    // lays out its children before we call getHitRect()
    public void run() {
        final Rect r = new Rect();
        delegate.getHitRect(r);
        r.top -= 4;
        r.bottom += 4;
        parent.setTouchDelegate( new TouchDelegate( r , delegate));
    }
});

How I can increase the touch area for controls (ToggleButton)?

Easy solution : If you have image for the button, then create transparent area around it (i.e. for touch area).

The grey area can be transparent to increase the touch area.

Or use TouchDelegate

Struggling with multiple use of Androids TouchDelegate

I found that when I add another LinearLayout around each row, both TouchDelegates work.

Now my example layout file looks like this:

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout android:id="@+id/layout_row_1"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content" >

            <Switch android:id="@+id/switch_row_1"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content" />
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout android:id="@+id/layout_row_2"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content" >

            <Switch android:id="@+id/switch_row_2"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content" />
        </LinearLayout>
    </LinearLayout>
</LinearLayout>

Maybe there is another solution. This one seems somehow tedious.

Strange behavior when enlarging rectangle for TouchDelegate

The reason of this such behavior, is due to the fact currency_exchange_linear_layout is NOT direct child of touch_delegate_linear_layout

Hence, when we perform

currencyExchangeLinearLayout.getHitRect(r);

The obtained rectangle's coordinate is not relative to touch_delegate_linear_layout

In such case, we may use footer_value_text_view's hit rectangle, which its rectangle's Y-coordinate is relative to touch_delegate_linear_layout

final View parentView = v.findViewById(R.id.touch_delegate_linear_layout);
final View directChildView = v.findViewById(R.id.footer_value_text_view);

ViewTreeObserver vto = parentView.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {

    @SuppressLint("NewApi")
    @SuppressWarnings("deprecation")
    @Override
    public void onGlobalLayout() {
        final Rect r = new Rect();
        final Rect directChild = new Rect();

        currencyExchangeLinearLayout.getHitRect(r);
        directChildView.getHitRect(directChild);

        int bestHeight = Utils.dpToPixel(48);

        directChild.top = directChild.bottom - Math.max((bestHeight - r.height()), 0);

        parentView.setTouchDelegate(new TouchDelegate(directChild, currencyExchangeLinearLayout));

        ViewTreeObserver obs = parentView.getViewTreeObserver();
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
            obs.removeOnGlobalLayoutListener(this);
        } else {
            obs.removeGlobalOnLayoutListener(this);
        }
    }
});

Increase the clickable area of the button

Just make the parent layout of the button (of larger size or clickable size), and perform click event of that like -

<LinearLayout
 android:id="@+id/backbuttonlayout"
        android:layout_width="50dp"
        android:layout_height="50dp">
<Button
        android:id="@+id/backbutton"
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="15dp"
        android:layout_marginTop="5dp"
        android:background="@drawable/arrow"
        android:paddingLeft="10dp"
        android:paddingRight="10dp"

        android:textColor="@color/title_gray"
        android:textSize="14sp"

        android:visibility="visible" />
</LinearLayout>

Now, inside your activity, do like -

LinearLayout backbuttonlayout = (LinearLayout)findViewById(R.id.backbuttonlayout);

and perform setOnClickListener() on backbuttonlayout

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