嵌入式大作业，车载多媒体开发+源代码+文档说明

/* * Copyright (C) 2011 The Android Open Source Project * * 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.wm.remusic.widget; import android.content.Context; import android.content.res.Resources; import android.content.res.TypedArray; import android.database.DataSetObserver; import android.graphics.Canvas; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.os.Build; import android.os.Bundle; import android.os.Parcel; import android.os.Parcelable; import android.os.SystemClock; import android.support.annotation.CallSuper; import android.support.annotation.DrawableRes; import android.support.v4.os.ParcelableCompat; import android.support.v4.os.ParcelableCompatCreatorCallbacks; import android.support.v4.view.AccessibilityDelegateCompat; import android.support.v4.view.KeyEventCompat; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.VelocityTrackerCompat; import android.support.v4.view.ViewCompat; import android.support.v4.view.ViewConfigurationCompat; import android.support.v4.view.ViewPager; import android.support.v4.view.WindowInsetsCompat; import android.support.v4.view.accessibility.AccessibilityEventCompat; import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat; import android.support.v4.view.accessibility.AccessibilityRecordCompat; import android.support.v4.widget.EdgeEffectCompat; import android.util.AttributeSet; import android.util.Log; import android.view.FocusFinder; import android.view.Gravity; import android.view.KeyEvent; import android.view.MotionEvent; import android.view.SoundEffectConstants; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.ViewParent; import android.view.accessibility.AccessibilityEvent; import android.view.animation.Animation; import android.view.animation.Interpolator; import android.widget.Scroller; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; /** * Layout manager that allows the user to flip left and right * through pages of data. You supply an implementation of a * {@link PagerAdapter} to generate the pages that the view shows. * * <p>Note this class is currently under early design and * development. The API will likely change in later updates of * the compatibility library, requiring changes to the source code * of apps when they are compiled against the newer version.</p> * * <p>ViewPager is most often used in conjunction with {@link android.app.Fragment}, * which is a convenient way to supply and manage the lifecycle of each page. * There are standard adapters implemented for using fragments with the ViewPager, * which cover the most common use cases. These are * {@link android.support.v4.app.FragmentPagerAdapter} and * {@link android.support.v4.app.FragmentStatePagerAdapter}; each of these * classes have simple code showing how to build a full user interface * with them. * * <p>For more information about how to use ViewPager, read <a * href="{@docRoot}training/implementing-navigation/lateral.html">Creating Swipe Views with * Tabs</a>.</p> * * <p>Below is a more complicated example of ViewPager, using it in conjunction * with {@link android.app.ActionBar} tabs. You can find other examples of using * ViewPager in the API 4+ Support Demos and API 13+ Support Demos sample code. * * {@sample development/samples/Support13Demos/src/com/example/android/supportv13/app/ActionBarTabsPager.java * complete} */ public class RoundViewPager extends ViewGroup { private static final String TAG = "ViewPager"; private static final boolean DEBUG = true; private static final boolean USE_CACHE = false; private static final int DEFAULT_OFFSCREEN_PAGES = 1; private static final int MAX_SETTLE_DURATION = 1000; // ms private static final int MIN_DISTANCE_FOR_FLING = 25; // dips private static final int DEFAULT_GUTTER_SIZE = 16; // dips private static final int MIN_FLING_VELOCITY = 400; // dips private static final int[] LAYOUT_ATTRS = new int[] { android.R.attr.layout_gravity }; /** * Used to track what the expected number of items in the adapter should be. * If the app changes this when we don't expect it, we'll throw a big obnoxious exception. */ private int mExpectedAdapterCount; static class ItemInfo { Object object; int position; boolean scrolling; float widthFactor; float offset; } private static final Comparator<ItemInfo> COMPARATOR = new Comparator<ItemInfo>(){ @Override public int compare(ItemInfo lhs, ItemInfo rhs) { return lhs.position - rhs.position; } }; private static final Interpolator sInterpolator = new Interpolator() { public float getInterpolation(float t) { t -= 1.0f; return t * t * t * t * t + 1.0f; } }; private final ArrayList<ItemInfo> mItems = new ArrayList<ItemInfo>(); private final ItemInfo mTempItem = new ItemInfo(); private final Rect mTempRect = new Rect(); private PagerAdapter mAdapter; private int mCurItem; // Index of currently displayed page. private int mRestoredCurItem = -1; private Parcelable mRestoredAdapterState = null; private ClassLoader mRestoredClassLoader = null; private Scroller mScroller; private boolean mIsScrollStarted; private PagerObserver mObserver; private int mPageMargin; private Drawable mMarginDrawable; private int mTopPageBounds; private int mBottomPageBounds; // Offsets of the first and lastPosition items, if known. // Set during population, used to determine if we are at the beginning // or end of the pager data set during touch scrolling. private float mFirstOffset = -Float.MAX_VALUE; private float mLastOffset = Float.MAX_VALUE; private int mChildWidthMeasureSpec; private int mChildHeightMeasureSpec; private boolean mInLayout; private boolean mScrollingCacheEnabled; private boolean mPopulatePending; private int mOffscreenPageLimit = DEFAULT_OFFSCREEN_PAGES; private boolean mIsBeingDragged; private boolean mIsUnableToDrag; private int mDefaultGutterSize; private int mGutterSize; private int mTouchSlop; /** * Position of the lastPosition motion event. */ private float mLastMotionX; private float mLastMotionY; private float mInitialMotionX; private float mInitialMotionY; /** * ID of the active pointer. This is used to retain consistency during * drags/flings if multiple pointers are used. */ private int mActivePointerId = INVALID_POINTER; /** * Sentinel value for no currentPosition active pointer. * Used by {@link #mActivePointerId}. */ private static final int INVALID_POINTER = -1; /** * Determines speed during touch scrolling */ private VelocityTracker mVelocityTracker; private int mMinimumVelocity; private int mMaximumVelocity; private int mFlingDistance; private int mCloseEnough; // If the pager is at least this close to its final position, complete the scroll // on touch down and let the user interact with the content inside instead of // "catching" the flinging