android 自定义View中滑动操作防止超出边界的简便方法

Posted 2023-04-01

参考技术A 在android开发中，自定义View中经常会用到滑动操作，肯定要防止滑动超出边界。这里是一个防止滑出边界非常简便的一个方法。

计算左右边界X或上下边界Y的值，如果不超出屏幕，左边边界与顶部边界是0，右边与底部边界是屏幕宽高度。然后重写scrollTo方法：

@Overridepublic void scrollTo(int x, int y)  

    ​if(x>mRightOffsetX) x=mRightOffsetX; 

    ​if(x<mLeftOffsetX) x=mLeftOffsetX; 

    ​super.scrollTo(x, y);

Android 自定义滑动解锁View

✏️ 丨 自定义滑动解锁View

1. 需求如下：

近期需要做一个类似屏幕滑动解锁的功能，右划开始，左划暂停。

2. 需求效果图如下

3. 实现效果展示

4. 自定义view如下

/**
 * Desc 自定义滑动解锁View
 * Author ZY
 * Mail [e-mail]
 * Date 2021/5/17 11:52
 */
@SuppressLint("ClickableViewAccessibility")
class SlideSwitchButton : ViewGroup 

    constructor(context: Context?) : this(context, null)
    constructor(context: Context?, attrs: AttributeSet?) : this(context, attrs, 0)
    constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : this(
        context,
        attrs,
        defStyleAttr, 0
    )

    constructor(
        context: Context?,
        attrs: AttributeSet?,
        defStyleAttr: Int,
        defStyleRes: Int
    ) : super(context, attrs, defStyleAttr, defStyleRes)


    var duration = 300

    var isOpen = false

    var scrollView: ScrollView? = null

    var onSwitchListener: ((isOpen: Boolean) -> Unit)? = null

    private var itemHeight = 0
    private var itemPadding = 0
    private var parentWidth = 0

    private val stopImgView: ImageView by lazy 
        ImageView(context).apply 
            setImageResource(R.drawable.f1_svg_btn_stop)
        
    

    private val startImgView: ImageView by lazy 
        ImageView(context).apply 
            setImageResource(R.drawable.f1_svg_btn_start)
        
    

    private val hintView: TextView by lazy 
        TextView(context).apply 
            setTextSize(TypedValue.COMPLEX_UNIT_PX, resources.getDimension(R.dimen.dp_14))
            compoundDrawablePadding = resources.getDimension(R.dimen.dp_5).toInt()
            setTextColor(Color.parseColor("#727b9f"))
        
    

    init 
        setBackgroundResource(R.drawable.f1_sel_bg_slide_btn)
        addView(hintView)
        updateHint()

        addView(stopImgView)
        addView(startImgView)

        var x = 0
        startImgView.setOnTouchListener  v, event ->

            when (event.action) 
                MotionEvent.ACTION_DOWN -> 
                    scrollView?.requestDisallowInterceptTouchEvent(true)
                    x = event.x.toInt()
                

                MotionEvent.ACTION_UP -> 

                    if (startImgView.x < (parentWidth - startImgView.width) / 2) 
                        play(false)
                     else 
                        play(true)
                    

                    scrollView?.requestDisallowInterceptTouchEvent(false)
                
                MotionEvent.ACTION_MOVE -> 
                    val lastX = event.x - x
                    if (startImgView.x + lastX > parentWidth - itemPadding - startImgView.width) 
                        return@setOnTouchListener true
                    

                    if (startImgView.x + lastX < itemPadding) 
                        return@setOnTouchListener true
                    
                    startImgView.x += lastX
                
            

            return@setOnTouchListener true
        
    


    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) 
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        setMeasuredDimension(widthMeasureSpec, resources.getDimension(R.dimen.dp_90).toInt())
        itemPadding = resources.getDimension(R.dimen.dp_5).toInt()
        itemHeight = resources.getDimension(R.dimen.dp_80).toInt()
        parentWidth = MeasureSpec.getSize(widthMeasureSpec)
    


    override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) 
        stopImgView.layout(
            itemPadding,
            itemPadding,
            itemPadding + itemHeight,
            itemPadding + itemHeight
        )

        startImgView.layout(
            itemPadding,
            itemPadding,
            itemPadding + itemHeight,
            itemPadding + itemHeight
        )

        val len =
            hintView.paint.measureText(hintView.text.toString()) + resources.getDimension(R.dimen.dp_24)
        val let = (r - len) / 2
        hintView.layout(
            let.toInt(),
            resources.getDimension(R.dimen.dp_35).toInt(),
            (let + len).toInt(),
            resources.getDimension(R.dimen.dp_55).toInt()
        )
    


    /**
     * flag tue为开始 false为停止
     */
    private fun play(flag: Boolean) 
        val mStart = startImgView.x
        val mEnd = if (flag) 
            parentWidth - itemPadding * 2 - startImgView.width.toFloat()
         else 
            stopImgView.x - itemPadding
        

        val animatorOBJ =
            ObjectAnimator.ofFloat(startImgView, "translationX", mStart, mEnd)
        animatorOBJ.duration = duration.toLong()
        animatorOBJ.addListener(object : Animator.AnimatorListener 
            override fun onAnimationRepeat(animation: Animator?) 

            

            override fun onAnimationEnd(animation: Animator?) 
                updateHint(flag)
                if (flag != isOpen) 
                    isOpen = flag
                    onSwitchListener?.invoke(flag)
                
            

            override fun onAnimationCancel(animation: Animator?) 

            

            override fun onAnimationStart(animation: Animator?) 

            
        )
        animatorOBJ.start()
    

    private fun updateHint(lock: Boolean = false) 
        val icon = if (lock) 
            hintView.text = "滑动停止"
            ResourcesCompat.getDrawable(resources, R.drawable.f1_svg_left_arrow, null)
         else 
            hintView.text = "滑动开始"
            ResourcesCompat.getDrawable(resources, R.drawable.f1_svg_right_arrow, null)
        
        icon?.setBounds(
            0,
            0,
            resources.getDimension(R.dimen.dp_14).toInt(),
            resources.getDimension(R.dimen.dp_12).toInt()
        )
        if (lock) 
            hintView.setCompoundDrawables(icon, null, null, null)
         else 
            hintView.setCompoundDrawables(null, null, icon, null)
        
    


    fun stop() 
        play(false)
    


    fun start() 
        play(true)
    

这里需要注意一点：页面过长时，ScrollView和SlideSwitchButton滑动事件会冲突，所以需要吧scrollView传进来

5. 调用方式如下

/**
 * Desc 自定义滑动解锁View
 * Author ZY
 * Mail [e-mail]
 * Date 2021/5/28 17:48
 */
class SlideSwitchButtonActivity : AppCompatActivity() 

    override fun onCreate(savedInstanceState: Bundle?) 
        super.onCreate(savedInstanceState)
        setContentView(R.layout.f1_act_main)

        btn_start.scrollView = scrollView

        btn_start.onSwitchListener = 
            if (it) 
                Toast.makeText(this,"开始操作",Toast.LENGTH_LONG).show()
                btn_start.start()
             else 
                Toast.makeText(this,"停止操作",Toast.LENGTH_LONG).show()
                btn_start.stop()
            
        
    

之前封装了一版ZyFrame框架，集工具类、自定义组件、网络请求框架一体，感觉用起来有些厚重，接下来会抽时间做拆分，ZyFrame保留网络请求功能，ZyUI专做自定义组件，ZyTool专做工具类，大概就酱紫。