ToggleButton 自定义控件的哪些坑

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更具项目需求，我需要写一个自定义的选择器，自己写有底气，用系统的togglebutton。。。。。。我宣简洁的啦（台湾腔读）··········

下面是我写的自定义控件：

注意：当设置回调函数的时候，要判断接口是否是null，因为如果不判断的话，会出很多问题。

如在activity中使用该控件，app会直接死掉。fragment中使用该控件的话，会直接导致fragment重新加载。。。。

最关键的是手机啥信息都不会反馈给你。。泪奔

public class ToggleButton extends View {    private Bitmap backgroundPic = null;    private Bitmap slideBtn;    private Paint paint;    private float slideBtn_letf = 0;    private static boolean currentState = false ;//开关状态 true为打开    private boolean isDrag = false; //是否是拖拽    private OnToggleStateChangedListener onToggleStateChangedListener = null;    public boolean isCurrentState() {        return currentState;    }    public void setCurrentState(boolean currentState) {        this.currentState = currentState;    }    public ToggleButton(Context context, AttributeSet attrs) {        super(context, attrs);                initView();    }    private void initView() {        backgroundPic = BitmapFactory.decodeResource(getResources() , R.mipmap.switch_background);        slideBtn = BitmapFactory.decodeResource(getResources() ,R.mipmap.slide_button);        paint = new Paint();        paint.setAntiAlias(true);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        setMeasuredDimension(backgroundPic.getWidth() ,backgroundPic.getHeight());    }    @Override    protected void onDraw(Canvas canvas) {        canvas.save();        canvas.drawBitmap(backgroundPic , 0 , 0 , paint);        canvas.drawBitmap(slideBtn , slideBtn_letf , 0 , paint);        canvas.restore();    }    private void flushState(){        if(currentState){            slideBtn_letf = backgroundPic.getWidth() - slideBtn.getWidth();        }else{            slideBtn_letf = 0;        }//        onToggleStateChangedListener.getCurrentState(currentState);        invalidate();    }    private void flushView(){        //对slideBtn的值进行判断，确保其在合理的位置        int maxLeft = backgroundPic.getWidth() - slideBtn.getWidth();        slideBtn_letf = (slideBtn_letf > 0) ? slideBtn_letf : 0;        slideBtn_letf = (slideBtn_letf < maxLeft) ? slideBtn_letf :maxLeft;//        invalidate();    }    private int firstX;    private int lastX;    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()){            case MotionEvent.ACTION_DOWN:                lastX = firstX = (int) event.getX();                isDrag = false;                break;            case MotionEvent.ACTION_MOVE:                if(Math.abs(event.getX() - firstX) > 5){                    int dis = (int) (event.getX() - lastX);                    slideBtn_letf += dis;                    isDrag = true;                }                break;            case MotionEvent.ACTION_UP:                int maxLetf = backgroundPic.getWidth() - slideBtn.getWidth();                if(slideBtn_letf > maxLetf /2){                    currentState = true;                    if(onToggleStateChangedListener != null){                        onToggleStateChangedListener.getCurrentState(currentState);                    }                }else{                    currentState = false;                    if(onToggleStateChangedListener != null){                        onToggleStateChangedListener.getCurrentState(currentState);                    }                }                flushState();                break;        }        flushView();        return true;    }    public interface OnToggleStateChangedListener{      public void  getCurrentState(boolean currentState);    }    public void setOnToggleStateChangeListener(OnToggleStateChangedListener onToggleStateChangeListener){        this.onToggleStateChangedListener = onToggleStateChangeListener;    }}

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