Launcher Workspace Demo

package com.zhaoyan; import android.app.WallpaperManager; import android.content.Context; import android.graphics.Canvas; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.os.IBinder; import android.os.Parcel; import android.os.Parcelable; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.ViewParent; import android.view.animation.Interpolator; import android.widget.Scroller; /** *Workspace是有数个屏幕宽的一个“桌面”，每屏都有用户可以交互的图标，目录或者widget。 */ public class Workspace extends ViewGroup { private static final String TAG = "MyLauncher.Workspace"; private static final int INVALID_SCREEN = -1; /** * The velocity at which a fling gesture will cause us to snap to the next screen */ private static final int SNAP_VELOCITY = 600; //fling手势速度，超过该值切换到下一屏幕 private final WallpaperManager mWallpaperManager; private int mDefaultScreen; private boolean mFirstLayout = true; private int mCurrentScreen; private int mNextScreen = INVALID_SCREEN; private Scroller mScroller; private VelocityTracker mVelocityTracker; /** * Target drop area calculated during last acceptDrop call. */ private int[] mTargetCell = null; private float mLastMotionX; private float mLastMotionY; private final static int TOUCH_STATE_REST = 0; private final static int TOUCH_STATE_SCROLLING = 1; private int mTouchState = TOUCH_STATE_REST; private OnLongClickListener mLongClickListener; private int[] mTempCell = new int[2]; private int[] mTempEstimate = new int[2]; private boolean mAllowLongPress = true; private int mTouchSlop; private int mMaximumVelocity; private static final int INVALID_POINTER = -1; private int mActivePointerId = INVALID_POINTER; private Drawable mPreviousIndicator; private Drawable mNextIndicator; private static final float NANOTIME_DIV = 1000000000.0f; private static final float SMOOTHING_SPEED = 0.75f; private static final float SMOOTHING_CONSTANT = (float) (0.016 / Math.log(SMOOTHING_SPEED)); private float mSmoothingTime; private float mTouchX; private WorkspaceOvershootInterpolator mScrollInterpolator; private static final float BASELINE_FLING_VELOCITY = 2500.f; private static final float FLING_VELOCITY_INFLUENCE = 0.4f; private static class WorkspaceOvershootInterpolator implements Interpolator { private static final float DEFAULT_TENSION = 1.3f; private float mTension; public WorkspaceOvershootInterpolator() { mTension = DEFAULT_TENSION; } public void setDistance(int distance) { mTension = distance > 0 ? DEFAULT_TENSION / distance : DEFAULT_TENSION; } public void disableSettle() { mTension = 0.f; } public float getInterpolation(float t) { // _o(t) = t * t * ((tension + 1) * t + tension) // o(t) = _o(t - 1) + 1 t -= 1.0f; return t * t * ((mTension + 1) * t + mTension) + 1.0f; } } /** * Used to inflate the Workspace from XML. * * @param context The application's context. * @param attrs The attribtues set containing the Workspace's customization values. */ public Workspace(Context context, AttributeSet attrs) { this(context, attrs, 0); } /** * Used to inflate the Workspace from XML. * * @param context The application's context. * @param attrs The attribtues set containing the Workspace's customization values. * @param defStyle Unused. */ public Workspace(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mWallpaperManager = WallpaperManager.getInstance(context); mDefaultScreen=0; /* TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Workspace, defStyle, 0); mDefaultScreen = a.getInt(R.styleable.Workspace_defaultScreen, 1); a.recycle(); */ setHapticFeedbackEnabled(false); initWorkspace(); } /** * Initializes various states for this workspace. */ private void initWorkspace() { Context context = getContext(); mScrollInterpolator = new WorkspaceOvershootInterpolator(); mScroller = new Scroller(context, mScrollInterpolator); mCurrentScreen = mDefaultScreen; final ViewConfiguration configuration = ViewConfiguration.get(getContext()); mTouchSlop = configuration.getScaledTouchSlop(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); } boolean isDefaultScreenShowing() { return mCurrentScreen == mDefaultScreen; } int getCurrentScreen() { return mCurrentScreen; } void setCurrentScreen(int currentScreen) { if (!mScroller.isFinished()) mScroller.abortAnimation(); mCurrentScreen = Math.max(0, Math.min(currentScreen, getChildCount() - 1)); scrollTo(mCurrentScreen * getWidth(), 0); invalidate(); } /** * Registers the specified listener on each screen contained in this workspace. * * @param l The listener used to respond to long clicks. */ @Override public void setOnLongClickListener(OnLongClickListener l) { mLongClickListener = l; final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).setOnLongClickListener(l); } } private void updateWallpaperOffset(int scrollRange) { IBinder token = getWindowToken(); if (token != null) { mWallpaperManager.setWallpaperOffsetSteps(1.0f / (getChildCount() - 1), 0 ); mWallpaperManager.setWallpaperOffsets(getWindowToken(), Math.max(0.f, Math.min(mScrollX/(float)scrollRange, 1.f)), 0); } } @Override public void scrollTo(int x, int y) { super.scrollTo(x, y); mTouchX = x; mSmoothingTime = System.nanoTime() / NANOTIME_DIV; } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { mTouchX = mScrollX = mScroller.getCurrX(); mSmoothingTime = System.nanoTime() / NANOTIME_DIV; mScrollY = mScroller.getCurrY(); postInvalidate(); } else if (mNextScreen != INVALID_SCREEN) { mCurrentScreen = Math.max(0, Math.min(mNextScreen, getChildCount() - 1)); //mPreviousIndicator.setLevel(mCurrentScreen); //mNextIndicator.setLevel(mCurrentScreen); mNextScreen = INVALID_SCREEN; //clearChildrenCache(); } else if (mTouchState == TOUCH_STATE_SCROLLING) { final float now = System.nanoTime() / NANOTIME_DIV; final float e = (float) Math.exp((now - mSmoothingTime) / SMOOTHING_CONSTANT); final float dx = mTouchX - mScrollX;