小程序 非常漂亮的滚动选择日期控件.rar

/* * Copyright (C) 2011 Daniel Berndt - Codeus Ltd - DateSlider * * This class contains all the scrolling logic of the slidable elements * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.googlecode.android.widgets.DateSlider; import java.lang.reflect.Constructor; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.drawable.Drawable; import android.util.AttributeSet; import android.util.Log; import android.view.Display; import android.view.Gravity; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.WindowManager; import android.widget.LinearLayout; import android.widget.Scroller; import com.googlecode.android.widgets.DateSlider.labeler.Labeler; import com.googlecode.android.widgets.DateSlider.timeview.TimeView; /** * This is where most of the magic happens. This is a subclass of LinearLayout * that display a collection of TimeViews and handles the scrolling, shuffling * the TimeViews around to keep the display up-to-date, and managing the Labelers * to populate the TimeViews with the correct data. * * This class is configured via xml attributes that specify the class of the * labeler to use to generate views, the format string for the labeler to use * to populate the views, and optionally width and height values to override * the default width and height of the views. */ public class ScrollLayout extends LinearLayout { private static String TAG = "SCROLLLAYOUT"; private Scroller mScroller; /** * Indicates if we are currently tracking touch events that are dragging * (scrolling) us. */ private boolean mDragMode; /** * The aggregate width of all of our children */ private int childrenWidth; /** * The aggregate width of our children is very likely to be wider than the * bounds of our view. Since we keep everything centered, we need to keep * our view scrolled by enough to center our children, rather than * left-aligning them. This variable tracks how much to scroll to achieve this. */ private int mInitialOffset; private int mLastX, mLastScroll, mScrollX; private VelocityTracker mVelocityTracker; private int mMinimumVelocity, mMaximumVelocity; /** * The time that we are currently displaying */ private long currentTime = System.currentTimeMillis(); private long minTime = -1, maxTime = -1; private int minuteInterval = 1; /** * The width of each child */ private int objWidth; /** * The height of each child */ private int objHeight; private Drawable rightShadow, leftShadow; private Labeler mLabeler; private OnScrollListener listener; private TimeView mCenterView; public ScrollLayout(Context context, AttributeSet attrs) { super(context, attrs); this.setWillNotDraw(false); rightShadow = getContext().getResources().getDrawable(R.drawable.right_shadow); leftShadow = getContext().getResources().getDrawable(R.drawable.left_shadow); mScroller = new Scroller(getContext()); setGravity(Gravity.CENTER_VERTICAL); setOrientation(HORIZONTAL); final ViewConfiguration configuration = ViewConfiguration.get(getContext()); mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); // as mMaximumVelocity does not exist in API<4 float density = getContext().getResources().getDisplayMetrics().density; mMaximumVelocity = (int)(4000 * 0.5f * density); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ScrollLayout, 0, 0); // Get the labeler class and construct an instance String className = a.getNonResourceString(R.styleable.ScrollLayout_labelerClass); if (className == null) { throw new RuntimeException("Must specify labeler class at " + a.getPositionDescription()); } String labelerFormat = a.getString(R.styleable.ScrollLayout_labelerFormat); if (labelerFormat == null) { throw new RuntimeException("Must specify labelerFormat at " + a.getPositionDescription()); } try { Class<?> klazz = Class.forName(className); Constructor<?> ctor = klazz.getConstructor(String.class); mLabeler = (Labeler)ctor.newInstance(labelerFormat); } catch (Exception e) { throw new RuntimeException("Failed to construct labeler at " + a.getPositionDescription(), e); } // Determine the width and height of our children, using the labelers preferred // values as defaults objWidth = a.getDimensionPixelSize(R.styleable.ScrollLayout_childWidth, mLabeler.getPreferredViewWidth(context)); objHeight = a.getDimensionPixelSize(R.styleable.ScrollLayout_childHeight, mLabeler.getPreferredViewHeight(context)); a.recycle(); } @Override protected void onFinishInflate() { super.onFinishInflate(); // // We need to generate enough children to fill all of our desired space, and // it needs to be an odd number of children because we treat the center view // specially. So, first compute how many children we will need. // final Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay(); final int displayWidth = display.getWidth(); int childCount = displayWidth / objWidth; // Make sure to round up if (displayWidth % objWidth != 0) { childCount++; } // Now make sure we have an odd number of children if (childCount % 2 == 0) { childCount++; } // We have an odd number of children, so childCount / 2 will round down to the // index just before the center in 1-based indexing, meaning that it will be the // center index in 0-based indexing. final int centerIndex = (childCount / 2); // Make sure we weren't inflated with any views for some odd reason removeAllViews(); // Now add all of the child views, making sure to make the center view as such. for (int i = 0; i < childCount; i++) { LayoutParams lp = new LayoutParams(objWidth, objHeight); TimeView ttv = mLabeler.createView(getContext(), i == centerIndex); addView((View)ttv, lp); } // Now we need to set the times on all of the TimeViews. We start with the center // view, work our way to the end, then starting from the center again, work our // way back to the beginning. mCenterView = (TimeView)getChildAt(centerIndex); mCenterView.setVals(mLabeler.getElem(currentTime)); Log.v(TAG, "mCenter: " + mCenterView.getTimeText() + " minInterval " + minuteInterval); // TODO: Do I need to use endTime, or can I just use the point time? for (int i = centerIndex + 1; i < childCount; i++) { TimeView lastView = (TimeView)getChildAt(i - 1); TimeView thisView = (TimeView)getChildAt(i); thisView.setVals(mLabeler.add(lastView.getEndTime(), 1)); } for (int i = centerIndex - 1; i >= 0; i--) { TimeVi