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如何監聽 SwitchCompat 小部件中的狀態變化?

[英]How to listen for state change in SwitchCompat widget?

如何監聽 SwitchCompat 小部件點擊? 我想在切換開關時執行一些語句。

尋找相當於

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

嘗試這個!

你只需要這個(setOnTouchListener 是不必要的):

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

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

隨着 Butterknife SwitchCompat 狀態改變

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

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

    }
}

現在可以在同一個回調中使用 isPressed 方法進行檢查。

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

我有同樣的問題 Slay 在對已接受答案的評論中解釋。 解決辦法來了!

我的解決方案,使用SwitchCompat和 Kotlin。 在我的情況下,只有當用戶通過 UI 觸發更改時,我才需要對更改做出反應。 事實上,我的開關對LiveData做出反應,這使得setOnClickListenersetOnCheckedChangeListener無法使用。 setOnClickListener實際上對用戶交互做出正確反應,但如果用戶將拇指拖過開關,則不會觸發它。 如果以編程方式切換開關(例如由觀察者),另一端的setOnCheckedChangeListener也會被觸發。 現在,在我的情況下,開關出現在兩個片段上,因此 onRestoreInstanceState 在某些情況下會觸發開關,舊值覆蓋正確的值。

所以,我查看了 SwitchCompat 的代碼,並且能夠成功地模仿它在區分點擊和拖動方面的行為,並使用它來構建一個可以正常工作的自定義觸摸偵聽器。 開始了:

/**
 * 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)
    }
}

如何使用它:

實際的觸摸偵聽器,它接受帶有要執行的代碼的 lambda:

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) 
    }
)

為了完整起見,這就是狀態switchstate的觀察者(如果有的話)的樣子:

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

其實你只需要這個:

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

就這樣!

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