Android自定义实现滚动选择器 |
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Android自定义实现滚动选择器
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在开发的过程中，现有的控件满足不了功能的需求，这个时候就需要我们自定义控件了。最近在开发中需要实现滚动进行类别的选择，也就是我们所说的滚动选择器，这里我们自定义来实现这个功能。 实现步骤： 1、先看需要实现的效果图 2、实现自定义控件(PickerScrollView ) 3、popupwindow实现类(CommonPopWindow ) 4.主界面(MainActivity) 5、实体类(GetConfigReq ) 6、底部弹出框布局文件 实现过程： 1、先看需要实现的效果图  在这里插入图片描述 2、实现自定义控件(PickerScrollView ) /** * 滚动选择器 */ public class PickerScrollView extends View { public static final String TAG = "PickerScrollView:"; /** * text之间间距和minTextSize之比 */ public static final float MARGIN_ALPHA = 2.8f; /** * 自动回滚到中间的速度 */ public static final float SPEED = 2; private List mDataList; /** * 选中的位置，这个位置是mDataList的中心位置，一直不变 */ private int mCurrentSelected; private Paint mPaint; private float mMaxTextSize = 20; private float mMinTextSize = 10; private float mMaxTextAlpha = 255; private float mMinTextAlpha = 120; private int mColorText = 0x333333; private int mViewHeight; private int mViewWidth; private float mLastDownY; /** * 滑动的距离 */ private float mMoveLen = 0; private boolean isInit = false; private onSelectListener mSelectListener; private Timer timer; private MyTimerTask mTask; Handler updateHandler = new Handler() { @Override public void handleMessage(Message msg) { if (Math.abs(mMoveLen) < SPEED) { mMoveLen = 0; if (mTask != null) { mTask.cancel(); mTask = null; performSelect(); } } else // 这里mMoveLen / Math.abs(mMoveLen)是为了保有mMoveLen的正负号，以实现上滚或下滚 mMoveLen = mMoveLen - mMoveLen / Math.abs(mMoveLen) * SPEED; invalidate(); } }; public PickerScrollView(Context context) { super(context); init(); } public PickerScrollView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public void setOnSelectListener(onSelectListener listener) { mSelectListener = listener; } private void performSelect() { if (mSelectListener != null) mSelectListener.onSelect(mDataList.get(mCurrentSelected)); } public void setData(List datas) { mDataList = datas; mCurrentSelected = datas.size() / 2; invalidate(); } /** * 选择选中的item的index * * @param selected */ public void setSelected(int selected) { mCurrentSelected = selected; int distance = mDataList.size() / 2 - mCurrentSelected; if (distance < 0) for (int i = 0; i < -distance; i++) { moveHeadToTail(); mCurrentSelected--; } else if (distance > 0) for (int i = 0; i < distance; i++) { moveTailToHead(); mCurrentSelected++; } invalidate(); } /** * 选择选中的内容 * * @param mSelectItem */ public void setSelected(String mSelectItem) { for (int i = 0; i < mDataList.size(); i++) if (mDataList.get(i).equals(mSelectItem)) { setSelected(i); break; } } private void moveHeadToTail() { GetConfigReq.DatasBean datasBean = mDataList.get(0); mDataList.remove(0); mDataList.add(datasBean); } private void moveTailToHead() { GetConfigReq.DatasBean datasBean = mDataList.get(mDataList.size() - 1); mDataList.remove(mDataList.size() - 1); mDataList.add(0, datasBean); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); mViewHeight = getMeasuredHeight(); mViewWidth = getMeasuredWidth(); // 按照View的高度计算字体大小 mMaxTextSize = mViewHeight / 8.0f; mMinTextSize = mMaxTextSize / 2f; isInit = true; invalidate(); } private void init() { timer = new Timer(); mDataList = new ArrayList(); mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setStyle(Paint.Style.FILL); mPaint.setTextAlign(Paint.Align.CENTER); mPaint.setColor(mColorText); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // 根据index绘制view if (isInit) drawData(canvas); } private void drawData(Canvas canvas) { // 先绘制选中的text再往上往下绘制其余的text float scale = parabola(mViewHeight / 4.0f, mMoveLen); float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize; mPaint.setTextSize(size); mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha)); // text居中绘制，注意baseline的计算才能达到居中，y值是text中心坐标 float x = (float) (mViewWidth / 2.0); float y = (float) (mViewHeight / 2.0 + mMoveLen); Paint.FontMetricsInt fmi = mPaint.getFontMetricsInt(); float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0)); int indexs = mCurrentSelected; String textData = mDataList.get(indexs).getCategoryName(); canvas.drawText(textData, x, baseline, mPaint); // 绘制上方data for (int i = 1; (mCurrentSelected - i) >= 0; i++) { drawOtherText(canvas, i, -1); } // 绘制下方data for (int i = 1; (mCurrentSelected + i) < mDataList.size(); i++) { drawOtherText(canvas, i, 1); } } /** * @param canvas * @param position 距离mCurrentSelected的差值 * @param type 1表示向下绘制，-1表示向上绘制 */ private void drawOtherText(Canvas canvas, int position, int type) { float d = (float) (MARGIN_ALPHA * mMinTextSize * position + type * mMoveLen); float scale = parabola(mViewHeight / 4.0f, d); float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize; mPaint.setTextSize(size); mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha)); float y = (float) (mViewHeight / 2.0 + type * d); Paint.FontMetricsInt fmi = mPaint.getFontMetricsInt(); float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0)); int indexs = mCurrentSelected + type * position; String textData = mDataList.get(indexs).getCategoryName(); canvas.drawText(textData, (float) (mViewWidth / 2.0), baseline, mPaint); } /** * 抛物线 * * @param zero 零点坐标 * @param x 偏移量 * @return scale */ private float parabola(float zero, float x) { float f = (float) (1 - Math.pow(x / zero, 2)); return f < 0 ? 0 : f; } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getActionMasked()) { case MotionEvent.ACTION_DOWN: doDown(event); break; case MotionEvent.ACTION_MOVE: doMove(event); break; case MotionEvent.ACTION_UP: doUp(event); break; } return true; } private void doDown(MotionEvent event) { if (mTask != null) { mTask.cancel(); mTask = null; } mLastDownY = event.getY(); } private void doMove(MotionEvent event) { mMoveLen += (event.getY() - mLastDownY); if (mMoveLen > MARGIN_ALPHA * mMinTextSize / 2) { // 往下滑超过离开距离 moveTailToHead(); mMoveLen = mMoveLen - MARGIN_ALPHA * mMinTextSize; } else if (mMoveLen < -MARGIN_ALPHA * mMinTextSize / 2) { // 往上滑超过离开距离 moveHeadToTail(); mMoveLen = mMoveLen + MARGIN_ALPHA * mMinTextSize; } mLastDownY = event.getY(); invalidate(); } private void doUp(MotionEvent event) { // 抬起手后mCurrentSelected的位置由当前位置move到中间选中位置 if (Math.abs(mMoveLen) < 0.0001) { mMoveLen = 0; return; } if (mTask != null) { mTask.cancel(); mTask = null; } mTask = new MyTimerTask(updateHandler); timer.schedule(mTask, 0, 10); } class MyTimerTask extends TimerTask { Handler handler; public MyTimerTask(Handler handler) { this.handler = handler; } @Override public void run() { handler.sendMessage(handler.obtainMessage()); } } public interface onSelectListener { void onSelect(GetConfigReq.DatasBean pickers); } }3、popupwindow实现类(CommonPopWindow ) /** * popupwindow */ public class CommonPopWindow { private static PopupWindow mPopupWindow; private static Builder mBuilder; private static View mContentView; private static Window mWindow; public interface ViewClickListener { void getChildView(PopupWindow mPopupWindow, View view, int mLayoutResId); } private CommonPopWindow() { mBuilder = new Builder(); } public static Builder newBuilder() { if (mBuilder == null) { mBuilder = new Builder(); } return mBuilder; } /** * 获取PopupWindow宽度 * * @return */ public int getWidth() { if (mPopupWindow != null) { return mContentView.getMeasuredWidth(); } return 0; } /** * 获取PopupWindow高度 * * @return */ public int getHeight() { if (mPopupWindow != null) { return mContentView.getMeasuredHeight(); } return 0; } /** * 显示在控件的下方 */ public CommonPopWindow showDownPop(View parent) { if (parent.getVisibility() == View.GONE) { mPopupWindow.showAtLocation(parent, Gravity.NO_GRAVITY, 0, 0); } else { int[] location = new int[2]; parent.getLocationOnScreen(location); if (mPopupWindow != null) { mPopupWindow.showAtLocation(parent, Gravity.NO_GRAVITY, location[0], location[1] + parent.getHeight()); } } return this; } /** * 显示在控件的上方 */ public CommonPopWindow showAsUp(View view) { if (view.getVisibility() == View.GONE) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, 0, 0); } else { int[] location = new int[2]; view.getLocationOnScreen(location); if (mPopupWindow != null) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, location[0], location[1] - view.getHeight()); //方式二 // mPopupWindow.showAsDropDown(view, 0, -(getHeight() + view.getMeasuredHeight())); } } return this; } /** * 显示在控件的左边 */ public CommonPopWindow showAsLeft(View view) { if (view.getVisibility() == View.GONE) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, 0, 0); } else { int[] location = new int[2]; view.getLocationOnScreen(location); if (mPopupWindow != null) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, location[0] - getWidth(), location[1]); } } return this; } /** * 显示在控件右边 */ public CommonPopWindow showAsRight(View view) { if (view.getVisibility() == View.GONE) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, 0, 0); } else { int[] location = new int[2]; view.getLocationOnScreen(location); if (mPopupWindow != null) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, location[0] + view.getWidth(), location[1]); } } return this; } /** * 显示控件下方 * * @param view * @return */ public CommonPopWindow showAsDown(View view) { if (mPopupWindow != null) { mPopupWindow.showAsDropDown(view); } return this; } /** * 全屏弹出 */ public CommonPopWindow showAsBottom(View view) { if (view.getVisibility() == View.GONE) { mPopupWindow.showAtLocation(view, Gravity.NO_GRAVITY, 0, 0); } else { int[] location = new int[2]; view.getLocationOnScreen(location); if (mPopupWindow != null) { mPopupWindow.showAtLocation(view, Gravity.BOTTOM, 0, 0); } } return this; } public CommonPopWindow showAtLocation(View anchor, int gravity, int x, int y) { if (mPopupWindow != null) { mPopupWindow.showAtLocation(anchor, gravity, x, y); } return this; } /** * 取消 */ public static void dismiss() { if (mWindow != null) { WindowManager.LayoutParams params = mWindow.getAttributes(); params.alpha = 1.0f; mWindow.setAttributes(params); } if (mPopupWindow != null && mPopupWindow.isShowing()) mPopupWindow.dismiss(); } /* * ---------------------Builder------------------------- */ public static class Builder implements PopupWindow.OnDismissListener { private Context mContext; private int mLayoutResId;//布局ID private int mWidth, mHeight;//弹窗宽高 private int mAnimationStyle;//动画样式 private ViewClickListener mListener;//子View监听回调 private Drawable mDrawable;//背景Drawable private boolean mTouchable = true;//是否相应touch事件 private boolean mFocusable = true;//是否获取焦点 private boolean mOutsideTouchable = true;//设置外部是否点击 private boolean mBackgroundDarkEnable = false;//是否背景窗体变暗 private float mDarkAlpha = 1.0f;//透明值 public CommonPopWindow build(Context context) { this.mContext = context; CommonPopWindow popWindow = new CommonPopWindow(); apply(); if (mListener != null && mLayoutResId != 0) { mListener.getChildView(mPopupWindow, mContentView, mLayoutResId); } return popWindow; } private void apply() { if (mLayoutResId != 0) { mContentView = LayoutInflater.from(mContext).inflate(mLayoutResId, null); } if (mWidth != 0 && mHeight != 0) { mPopupWindow = new PopupWindow(mContentView, mWidth, mHeight); } else { mPopupWindow = new PopupWindow(mContentView, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); } mPopupWindow.setTouchable(mTouchable); mPopupWindow.setFocusable(mFocusable); mPopupWindow.setOutsideTouchable(mOutsideTouchable); if (mDrawable != null) { mPopupWindow.setBackgroundDrawable(mDrawable); } else { mPopupWindow.setBackgroundDrawable(new ColorDrawable()); } if (mAnimationStyle != -1) { mPopupWindow.setAnimationStyle(mAnimationStyle); } if (mWidth == 0 || mHeight == 0) { measureWidthAndHeight(mContentView); //如果没有设置高度的情况下，设置宽高并赋值 mWidth = mPopupWindow.getContentView().getMeasuredWidth(); mHeight = mPopupWindow.getContentView().getMeasuredHeight(); } Activity activity = (Activity) mContext; if (activity != null && mBackgroundDarkEnable) { float alpha = (mDarkAlpha >= 0f || mDarkAlpha |
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