Workspace

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2013年11月11日 ⁄ 综合 ⁄ 共 14841字 ⁄ 字号小中大 ⁄ 评论关闭

/** * Copyright 2010 Eric Taix (eric.taix@gmail.com) 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 me.imonkey.iphonelauncher; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; 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.widget.Scroller; /** * The workspace is a wide area with a infinite number of screens. Each screen contains a view. A workspace is meant to * be used with a fixed width only. * * This code has been done by using com.android.launcher.Workspace.java */ public class Workspace extends ViewGroup { 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 = 1000; // the default screen index private int defaultScreen; // The current screen index private int currentScreen; // The next screen index private int nextScreen = INVALID_SCREEN; // Wallpaper properties private Bitmap wallpaper; private Paint paint; private int wallpaperWidth; private int wallpaperHeight; private float wallpaperOffset; private boolean wallpaperLoaded; private boolean firstWallpaperLayout = true; // The scroller which scroll each view private Scroller scroller; // A tracker which to calculate the velocity of a mouvement private VelocityTracker mVelocityTracker; // Tha last known values of X and Y private float lastMotionX; private float lastMotionY; private final static int TOUCH_STATE_REST = 0; private final static int TOUCH_STATE_SCROLLING = 1; // The current touch state private int touchState = TOUCH_STATE_REST; // The minimal distance of a touch slop private int touchSlop; // An internal flag to reset long press when user is scrolling private boolean allowLongPress; // A flag to know if touch event have to be ignored. Used also in internal private boolean locked; /** * 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); defaultScreen = 0; initWorkspace(); } /** * Initializes various states for this workspace. */ private void initWorkspace() { scroller = new Scroller(getContext()); currentScreen = defaultScreen; paint = new Paint(); paint.setDither(false); touchSlop = ViewConfiguration.getTouchSlop(); } /** * Set a new distance that a touch can wander before we think the user is scrolling in pixels slop * * @param touchSlopP */ public void setTouchSlop(int touchSlopP) { touchSlop = touchSlopP; } /** * Set the background's wallpaper. */ public void loadWallpaper(Bitmap bitmap) { wallpaper = bitmap; wallpaperLoaded = true; requestLayout(); invalidate(); } boolean isDefaultScreenShowing() { return currentScreen == defaultScreen; } /** * Returns the index of the currently displayed screen. * * @return The index of the currently displayed screen. */ int getCurrentScreen() { return currentScreen; } /** * Sets the current screen. * * @param currentScreen */ void setCurrentScreen(int currentScreen) { currentScreen = Math.max(0, Math.min(currentScreen, getChildCount())); scrollTo(currentScreen * getWidth(), 0); invalidate(); } /** * Shows the default screen (defined by the firstScreen attribute in XML.) */ void showDefaultScreen() { setCurrentScreen(defaultScreen); } /** * 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) { final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).setOnLongClickListener(l); } } @Override public void computeScroll() { if (scroller.computeScrollOffset()) { scrollTo(scroller.getCurrX(), scroller.getCurrY()); } else if (nextScreen != INVALID_SCREEN) { currentScreen = nextScreen; nextScreen = INVALID_SCREEN; } } /** * ViewGroup.dispatchDraw() supports many features we don't need: clip to padding, layout animation, animation * listener, disappearing children, etc. The following implementation attempts to fast-track the drawing dispatch by * drawing only what we know needs to be drawn. */ @Override protected void dispatchDraw(Canvas canvas) { // First draw the wallpaper if needed if (wallpaper != null) { float x = getScrollX() * wallpaperOffset; if (x + wallpaperWidth < getRight() - getLeft()) { x = getRight() - getLeft() - wallpaperWidth; } canvas.drawBitmap(wallpaper, x, (getBottom() - getTop() - wallpaperHeight) / 2, paint); } // Determine if we need to draw every child or only the current screen boolean fastDraw = touchState != TOUCH_STATE_SCROLLING && nextScreen == INVALID_SCREEN; // If we are not scrolling or flinging, draw only the current screen if (fastDraw) { View v = getChildAt(currentScreen); drawChild(canvas, v, getDrawingTime()); } else { final long drawingTime = getDrawingTime(); // If we are flinging, draw only the current screen and the target screen if (nextScreen >= 0 && nextScreen < getChildCount() && Math.abs(currentScreen - nextScreen) == 1) { drawChild(canvas, getChildAt(currentScreen), drawingTime); drawChild(canvas, getChildAt(nextScreen), drawingTime); } else { // If we are scrolling, draw all of our children final int count = getChildCount(); for (int i = 0; i < count; i++) { drawChild(canvas, getChildAt(i), drawingTime); } } } } /** * Measure the workspace AND also children */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int width = MeasureSpec.getSize(widthMeasureSpec); final int widthMode = MeasureSpec.getMode(widthMeasureSpec); if (widthMode != MeasureSpec.EXACTLY) { throw new IllegalStateException("Workspace can only be used in EXACTLY mode."); } final int heightMode = MeasureSpec.getMode(heightMeasureSpec); if (heightMode != MeasureSpec.EXACTLY) { throw new IllegalStateException("Workspace can only be used in EXACTLY mode."); } // The children are given the same width and height as the workspace final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } // Compute wallpaper if (wallpaperLoaded) { wallpaperLoaded = false; wallpaper = centerToFit(wallpaper, width, MeasureSpec.getSize(heightMeasureSpec), getContext()); wallpaperWidth = wallpaper.getWidth(); wallpaperHeight = wallpaper.getHeight(); } wallpaperOffset = wallpaperWidth > width ? (count * width - wallpaperWidth) / ((count - 1) * (float) width) : 1.0f; if (firstWallpaperLayout) { scrollTo(currentScreen * width, 0); firstWallpaperLayout = false; } } /** * Overrided method to layout child */ @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { int childLeft = 0; final int count = getChildCount(); for (int i = 0; i < count; i++) { final View child = getChildAt(i); if (child.getVisibility() != View.GONE) { final int childWidth = child.getMeasuredWidth(); child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight()); childLeft += childWidth; } } } @Override public boolean dispatchUnhandledMove(View focused, int direction) { if (direction == View.FOCUS_LEFT) { if (getCurrentScreen() > 0) { scrollToScreen(getCurrentScreen() - 1); return true; } } else if (direction == View.FOCUS_RIGHT) { if (getCurrentScreen() < getChildCount() - 1) { scrollToScreen(getCurrentScreen() + 1); return true; } } return super.dispatchUnhandledMove(focused, direction); } /** * This method JUST determines whether we want to intercept the motion. If we return true, onTouchEvent will be called * and we do the actual scrolling there. */ @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (locked) { return true; } /* * Shortcut the most recurring case: the user is in the dragging state and he is moving his finger. We want to * intercept this motion. */ final int action = ev.getAction(); if ((action == MotionEvent.ACTION_MOVE) && (touchState != TOUCH_STATE_REST)) { return true; } final float x = ev.getX(); final float y = ev.getY(); switch (action) { case MotionEvent.ACTION_MOVE: /* * Locally do absolute value. mLastMotionX is set to the y value of the down event. */ final int xDiff = (int) Math.abs(x - lastMotionX); final int yDiff = (int) Math.abs(y - lastMotionY); boolean xMoved = xDiff > touchSlop; boolean yMoved = yDiff > touchSlop; if (xMoved || yMoved) { if (xMoved && !yMoved) { // Scroll if the user moved far enough along the X axis touchState = TOUCH_STATE_SCROLLING; } // Either way, cancel any pending longpress if (allowLongPress) { allowLongPress = false; // Try canceling the long press. It could also have been scheduled // by a distant descendant, so use the mAllowLongPress flag to block // everything final View currentView = getChildAt(currentScreen); currentView.cancelLongPress(); } } break; case MotionEvent.ACTION_DOWN: // Remember location of down touch lastMotionX = x; lastMotionY = y; allowLongPress = true; /* * If being flinged and user touches the screen, initiate drag; otherwise don't. mScroller.isFinished should be * false when being flinged. */ touchState = scroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; break; case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: touchState = TOUCH_STATE_REST; break; } /* * The only time we want to intercept motion events is if we are in the drag mode. */ return touchState != TOUCH_STATE_REST; } /** * Track the touch event */ @Override public boolean onTouchEvent(MotionEvent ev) { if (locked) { return true; } if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: /* * If being flinged and user touches, stop the fling. isFinished will be false if being flinged. */ if (!scroller.isFinished()) { scroller.abortAnimation(); } // Remember where the motion event started lastMotionX = x; break; case MotionEvent.ACTION_MOVE: if (touchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event final int deltaX = (int) (lastMotionX - x); lastMotionX = x; if (deltaX < 0) { if (getScrollX() > 0) { scrollBy(Math.max(-getScrollX(), deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt(getChildCount() - 1).getRight() - getScrollX() - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } } break; case MotionEvent.ACTION_UP: if (touchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && currentScreen > 0) { // Fling hard enough to move left scrollToScreen(currentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && currentScreen < getChildCount() - 1) { // Fling hard enough to move right scrollToScreen(currentScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } touchState = TOUCH_STATE_REST; break; case MotionEvent.ACTION_CANCEL: touchState = TOUCH_STATE_REST; } return true; } /** * Scroll to the appropriated screen depending of the current position */ private void snapToDestination() { final int screenWidth = getWidth(); final int whichScreen = (getScrollX() + (screenWidth / 2)) / screenWidth; Log.d("workspace", "snapToDestination"); scrollToScreen(whichScreen); } /** * Scroll to a specific screen * * @param whichScreen */ public void scrollToScreen(int whichScreen) { Log.d("workspace", "snapToScreen=" + whichScreen); boolean changingScreens = whichScreen != currentScreen; nextScreen = whichScreen; View focusedChild = getFocusedChild(); if (focusedChild != null && changingScreens && focusedChild == getChildAt(currentScreen)) { focusedChild.clearFocus(); } final int newX = whichScreen * getWidth(); final int delta = newX - getScrollX(); Log.d("workspace", "newX=" + newX + " scrollX=" + getScrollX() + " delta=" + delta); scroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta) * 2); invalidate(); } /** * Return the parceable instance to be saved */ @Override protected Parcelable onSaveInstanceState() { final SavedState state = new SavedState(super.onSaveInstanceState()); state.currentScreen = currentScreen; return state; } /** * Restore the previous saved current screen */ @Override protected void onRestoreInstanceState(Parcelable state) { SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); if (savedState.currentScreen != -1) { currentScreen = savedState.currentScreen; } } /** * Scroll to the left right screen */ public void scrollLeft() { if (nextScreen == INVALID_SCREEN && currentScreen > 0 && scroller.isFinished()) { scrollToScreen(currentScreen - 1); } } /** * Scroll to the next right screen */ public void scrollRight() { if (nextScreen == INVALID_SCREEN && currentScreen < getChildCount() - 1 && scroller.isFinished()) { scrollToScreen(currentScreen + 1); } } /** * Return the screen's index where a view has been added to. * * @param v * @return */ public int getScreenForView(View v) { int result = -1; if (v != null) { ViewParent vp = v.getParent(); int count = getChildCount(); for (int i = 0; i < count; i++) { if (vp == getChildAt(i)) { return i; } } } return result; } /** * Return a view instance according to the tag parameter or null if the view could not be found * * @param tag * @return */ public View getViewForTag(Object tag) { int screenCount = getChildCount(); for (int screen = 0; screen < screenCount; screen++) { View child = getChildAt(screen); if (child.getTag() == tag) { return child; } } return null; } /** * Unlocks the SlidingDrawer so that touch events are processed. * * @see #lock() */ public void unlock() { locked = false; } /** * Locks the SlidingDrawer so that touch events are ignores. * * @see #unlock() */ public void lock() { locked = true; } /** * @return True is long presses are still allowed for the current touch */ public boolean allowLongPress() { return allowLongPress; } /** * Move to the default screen */ public void moveToDefaultScreen() { scrollToScreen(defaultScreen); getChildAt(defaultScreen).requestFocus(); } // ========================= INNER CLASSES ============================== /** * A SavedState which save and load the current screen */ public static class SavedState extends BaseSavedState { int currentScreen = -1; /** * Internal constructor * * @param superState */ SavedState(Parcelable superState) { super(superState); } /** * Private constructor * * @param in */ private SavedState(Parcel in) { super(in); currentScreen = in.readInt(); } /** * Save the current screen */ @Override public void writeToParcel(Parcel out, int flags) { super.writeToParcel(out, flags); out.writeInt(currentScreen); } /** * Return a Parcelable creator */ public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState createFromParcel(Parcel in) { return new SavedState(in); } public SavedState[] newArray(int size) { return new SavedState[size]; } }; } // ======================== UTILITIES METHODS ========================== /** * Return a centered Bitmap * * @param bitmap * @param width * @param height * @param context * @return */ static Bitmap centerToFit(Bitmap bitmap, int width, int height, Context context) { final int bitmapWidth = bitmap.getWidth(); final int bitmapHeight = bitmap.getHeight(); if (bitmapWidth < width || bitmapHeight < height) { // Normally should get the window_background color of the context int color = Integer.valueOf("00191919", 16); Bitmap centered = Bitmap.createBitmap(bitmapWidth < width ? width : bitmapWidth, bitmapHeight < height ? height : bitmapHeight, Bitmap.Config.RGB_565); Canvas canvas = new Canvas(centered); canvas.drawColor(color); canvas.drawBitmap(bitmap, (width - bitmapWidth) / 2.0f, (height - bitmapHeight) / 2.0f, null); bitmap = centered; } return bitmap; } }

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该日志由 cssi7136 于10年前发表在综合分类下，最后更新于 2013年11月11日.
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