如何监听 SwitchCompat 小部件中的状态变化？

Question

How to listen for SwitchCompat widget clicks? I want to execute a few statements when the Switch is toggled.

Looking for an equivalent of

button.setOnClickListener(new View.OnClickListener() {
    @Override
        public void onClick(View view) {
        //Do something
    }
});

Answer 1

static Boolean isTouched = false;

switchButton.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent) {
                isTouched = true;
                return false;
            }
        });

switchButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener()
    {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)
        {
            if (isTouched) {
                isTouched = false;
                if (isChecked) {
                }
                else {
                }
            }
        }
    });

Try this!

Answer 2

you need only this(the setOnTouchListener is unnecessary):

switchButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener()
    {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)
        {

                if (isChecked) {
                     //if 'isChecked' is true do whatever you need...
                }
                else {
                }
            }
        }
    });

Answer 3

With Butterknife SwitchCompat state change

  @OnCheckedChanged(R.id.switchCompat)
  public void onCheckedChanged(SwitchCompat switchCompat, boolean isChecked) {
    Log.i("skh", "check:" + isChecked);

    if (isChecked) {
        // Log.i("skh","check:"+isChecked);
    } else {

    }
}

Answer 4

Now it's possible to check with isPressed method within the same callback.

    switchCompat.setOnCheckedChangeListener { buttonView, isChecked ->
        if (buttonView?.isPressed == true) {
            // todo
        } else {
            
        }
    }

Answer 5

I had the same problem Slay explains on the comment to the accepted answer. Here the solution!

My solution, using a SwitchCompat and Kotlin. In my situation, i needed to react to a change only if the user triggered it through the UI. In fact, my switch reacts to a LiveData , and this made both setOnClickListener and setOnCheckedChangeListener unusable. setOnClickListener in fact reacts correctly to user interaction, but it's not triggered if the user drags the thumb across the switch. setOnCheckedChangeListener on the other end is triggered also if the switch is toggled programmatically (for example by an observer). Now in my case the switch was present on two fragments, and so onRestoreInstanceState would trigger in some cases the switch with an old value overwriting the correct value.

So, i looked at the code of SwitchCompat, and was able to mimic it's behaviour successfully in distinguishing click and drag and used that to build a custom touchlistener that works as it should. Here we go:

/**
 * This function calls the lambda function passed with the right value of isChecked
 * when the switch is tapped with single click isChecked is relative to the current position so we pass !isChecked
 * when the switch is dragged instead, the position of the thumb centre where the user leaves the
 * thumb is compared to the middle of the switch, and we assume that left means false, right means true
 * (there is no rtl or vertical switch management)
 * The behaviour is extrapolated from the SwitchCompat source code
 */
class SwitchCompatTouchListener(private val v: SwitchCompat, private val lambda: (Boolean)->Unit) :  View.OnTouchListener {
    companion object {
        private const val TOUCH_MODE_IDLE = 0
        private const val TOUCH_MODE_DOWN = 1
        private const val TOUCH_MODE_DRAGGING = 2
    }

    private val vc = ViewConfiguration.get(v.context)
    private val mScaledTouchSlop = vc.scaledTouchSlop
    private var mTouchMode = 0
    private var mTouchX = 0f
    private var mTouchY = 0f

    /**
     * @return true if (x, y) is within the target area of the switch thumb
     * x,y and rect are in view coordinates, 0,0 is top left of the view
     */
    private fun hitThumb(x: Float, y: Float): Boolean {
        val rect = v.thumbDrawable.bounds
        return x >= rect.left && x <= rect.right && y >= rect.top && y <= rect.bottom
    }

    override fun onTouch(view: View, event: MotionEvent): Boolean {
        if (view == v) {
            when (MotionEventCompat.getActionMasked(event)) {
                MotionEvent.ACTION_DOWN -> {
                    val x = event.x
                    val y = event.y
                    if (v.isEnabled && hitThumb(x, y)) {
                        mTouchMode = TOUCH_MODE_DOWN;
                        mTouchX = x;
                        mTouchY = y;
                    }
                }
                MotionEvent.ACTION_MOVE -> {
                    val x = event.x
                    val y = event.y
                    if (mTouchMode == TOUCH_MODE_DOWN &&
                        (abs(x - mTouchX) > mScaledTouchSlop || abs(y - mTouchY) > mScaledTouchSlop)
                    )
                        mTouchMode = TOUCH_MODE_DRAGGING;
                }
                MotionEvent.ACTION_UP,
                MotionEvent.ACTION_CANCEL -> {
                    if (mTouchMode == TOUCH_MODE_DRAGGING) {
                        val r = v.thumbDrawable.bounds
                        if (r.left + r.right < v.width) lambda(false)
                        else lambda(true)
                    } else lambda(!v.isChecked)
                    mTouchMode = TOUCH_MODE_IDLE;
                }
            }
        }
        return v.onTouchEvent(event)
    }
}

How to use it:

the actual touch listener that accepts a lambda with the code to execute:

myswitch.setOnTouchListener(
    SwitchCompatTouchListener(myswitch) {
        // here goes all the code for your callback, in my case
        // i called a service which, when successful, in turn would 
        // update my liveData 
        viewModel.sendCommandToMyService(it) 
    }
)

For the sake of completeness, this is how the observer for the state switchstate (if you have it) looked like:

switchstate.observe(this, Observer {
    myswitch.isChecked = it
})

Answer 6

Actually, you just need this:

if (yourSwitchButton.isChecked()) {
//do what you want here
} else{
//do what you want here
}

That's all!