源码简介：TopNews高仿“今日头条”客户端,1.slidingmenu 侧拉菜单 2.UniversalImageLoader 目前***的图片异步加载库，配置强大，使用简单，绝对能满足你的各种需求！ 高仿“今日头条”客户端，实现它大部分的功能，练习之作，目的了解怎么发开一个新闻类客户端，从涉及的相关知识点中提升自我水平
源码效果：
源码片段：
package com.jeremyfeinstein.slidingmenu.lib;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Build;
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.util.AttributeSet;
import android.util.FloatMath;
import android.util.Log;
import android.view.FocusFinder;
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.animation.Interpolator;
import android.widget.Scroller;
import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnClosedListener;
import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnOpenedListener;
//import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnCloseListener;
//import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnOpenListener;
public class CustomViewAbove extends ViewGroup {
private static final String TAG = "CustomViewAbove";
private static final boolean DEBUG = false;
private static final boolean USE_CACHE = false;
private static final int MAX_SETTLE_DURATION = 600; // ms
private static final int MIN_DISTANCE_FOR_FLING = 25; // dips
private static final Interpolator sInterpolator = new Interpolator() {
public float getInterpolation(float t) {
t -= 1.0f;
return t * t * t * t * t + 1.0f;
}
};
private View mContent;
private int mCurItem;
private Scroller mScroller;
private boolean mScrollingCacheEnabled;
private boolean mScrolling;
private boolean mIsBeingDragged;
private boolean mIsUnableToDrag;
private int mTouchSlop;
private float mInitialMotionX;
/**
* Position of the last motion event.
*/
private float mLastMotionX;
private float mLastMotionY;
/**
* ID of the active pointer. This is used to retain consistency during
* drags/flings if multiple pointers are used.
*/
protected int mActivePointerId = INVALID_POINTER;
/**
* Sentinel value for no current active pointer.
* Used by {@link #mActivePointerId}.
*/
private static final int INVALID_POINTER = -1;
/**
* Determines speed during touch scrolling
*/
protected VelocityTracker mVelocityTracker;
private int mMinimumVelocity;
protected int mMaximumVelocity;
private int mFlingDistance;
private CustomViewBehind mViewBehind;
// private int mMode;
private boolean mEnabled = true;
private OnPageChangeListener mOnPageChangeListener;
private OnPageChangeListener mInternalPageChangeListener;
// private OnCloseListener mCloseListener;
// private OnOpenListener mOpenListener;
private OnClosedListener mClosedListener;
private OnOpenedListener mOpenedListener;
private List<view> mIgnoredViews = new ArrayList<view>();
// private int mScrollState = SCROLL_STATE_IDLE;
/**
* Callback interface for responding to changing state of the selected page.
*/
public interface OnPageChangeListener {
/**
* This method will be invoked when the current page is scrolled, either as part
* of a programmatically initiated smooth scroll or a user initiated touch scroll.
*
* @param position Position index of the first page currently being displayed.
* Page position+1 will be visible if positionOffset is nonzero.
* @param positionOffset Value from [0, 1) indicating the offset from the page at position.
* @param positionOffsetPixels Value in pixels indicating the offset from position.
*/
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels);
/**
* This method will be invoked when a new page becomes selected. Animation is not
* necessarily complete.
*
* @param position Position index of the new selected page.
*/
public void onPageSelected(int position);
}
/**
* Simple implementation of the {@link OnPageChangeListener} interface with stub
* implementations of each method. Extend this if you do not intend to override
* every method of {@link OnPageChangeListener}.
*/
public static class SimpleOnPageChangeListener implements OnPageChangeListener {
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// This space for rent
}
public void onPageSelected(int position) {
// This space for rent
}
public void onPageScrollStateChanged(int state) {
// This space for rent
}
}
public CustomViewAbove(Context context) {
this(context, null);
}
public CustomViewAbove(Context context, AttributeSet attrs) {
super(context, attrs);
initCustomViewAbove();
}
void initCustomViewAbove() {
setWillNotDraw(false);
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
setFocusable(true);
final Context context = getContext();
mScroller = new Scroller(context, sInterpolator);
final ViewConfiguration configuration = ViewConfiguration.get(context);
mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
setInternalPageChangeListener(new SimpleOnPageChangeListener() {
public void onPageSelected(int position) {
if (mViewBehind != null) {
switch (position) {
case 0:
case 2:
mViewBehind.setChildrenEnabled(true);
break;
case 1:
mViewBehind.setChildrenEnabled(false);
break;
}
}
}
});
final float density = context.getResources().getDisplayMetrics().density;
mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
}
/**
* Set the currently selected page. If the CustomViewPager has already been through its first
* layout there will be a smooth animated transition between the current item and the
* specified item.
*
* @param item Item index to select
*/
public void setCurrentItem(int item) {
setCurrentItemInternal(item, true, false);
}
/**
* Set the currently selected page.
*
* @param item Item index to select
* @param smoothScroll True to smoothly scroll to the new item, false to transition immediately
*/
public void setCurrentItem(int item, boolean smoothScroll) {
setCurrentItemInternal(item, smoothScroll, false);
}
public int getCurrentItem() {
return mCurItem;
}
void setCurrentItemInternal(int item, boolean smoothScroll, boolean always) {
setCurrentItemInternal(item, smoothScroll, always, 0);
}
void setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) {
if (!always && mCurItem == item) {
setScrollingCacheEnabled(false);
return;
}
item = mViewBehind.getMenuPage(item);
final boolean dispatchSelected = mCurItem != item;
mCurItem = item;
final int destX = getDestScrollX(mCurItem);
if (dispatchSelected && mOnPageChangeListener != null) {
mOnPageChangeListener.onPageSelected(item);
}
if (dispatchSelected && mInternalPageChangeListener != null) {
mInternalPageChangeListener.onPageSelected(item);
}
if (smoothScroll) {
smoothScrollTo(destX, 0, velocity);
} else {
completeScroll();
scrollTo(destX, 0);
}
}
/**
* Set a listener that will be invoked whenever the page changes or is incrementally
* scrolled. See {@link OnPageChangeListener}.
*
* @param listener Listener to set
*/
public void setOnPageChangeListener(OnPageChangeListener listener) {
mOnPageChangeListener = listener;
}
/*
public void setOnOpenListener(OnOpenListener l) {
mOpenListener = l;
}
public void setOnCloseListener(OnCloseListener l) {
mCloseListener = l;
}
*/
public void setOnOpenedListener(OnOpenedListener l) {
mOpenedListener = l;
}
public void setOnClosedListener(OnClosedListener l) {
mClosedListener = l;
}
/**
* Set a separate OnPageChangeListener for internal use by the support library.
*
* @param listener Listener to set
* @return The old listener that was set, if any.
*/
OnPageChangeListener setInternalPageChangeListener(OnPageChangeListener listener) {
OnPageChangeListener oldListener = mInternalPageChangeListener;
mInternalPageChangeListener = listener;
return oldListener;
}
public void addIgnoredView(View v) {
if (!mIgnoredViews.contains(v)) {
mIgnoredViews.add(v);
}
}
public void removeIgnoredView(View v) {
mIgnoredViews.remove(v);
}
public void clearIgnoredViews() {
mIgnoredViews.clear();
}
// We want the duration of the page snap animation to be influenced by the distance that
// the screen has to travel, however, we don't want this duration to be effected in a
// purely linear fashion. Instead, we use this method to moderate the effect that the distance
// of travel has on the overall snap duration.
float distanceInfluenceForSnapDuration(float f) {
f -= 0.5f; // center the values about 0.
f *= 0.3f * Math.PI / 2.0f;
return (float) FloatMath.sin(f);
}
public int getDestScrollX(int page) {
switch (page) {
case 0:
case 2:
return mViewBehind.getMenuLeft(mContent, page);
case 1:
return mContent.getLeft();
}
return 0;
}
private int getLeftBound() {
return mViewBehind.getAbsLeftBound(mContent);
}
private int getRightBound() {
return mViewBehind.getAbsRightBound(mContent);
}
public int getContentLeft() {
return mContent.getLeft() + mContent.getPaddingLeft();
}
public boolean isMenuOpen() {
return mCurItem == 0 || mCurItem == 2;
}
private boolean isInIgnoredView(MotionEvent ev) {
Rect rect = new Rect();
for (View v : mIgnoredViews) {
v.getHitRect(rect);
if (rect.contains((int)ev.getX(), (int)ev.getY())) return true;
}
return false;
}
public int getBehindWidth() {
if (mViewBehind == null) {
return 0;
} else {
return mViewBehind.getBehindWidth();
}
}
public int getChildWidth(int i) {
switch (i) {
case 0:
return getBehindWidth();
case 1:
return mContent.getWidth();
default:
return 0;
}
}
public boolean isSlidingEnabled() {
return mEnabled;
}
public void setSlidingEnabled(boolean b) {
mEnabled = b;
}
/**
* Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
*
* @param x the number of pixels to scroll by on the X axis
* @param y the number of pixels to scroll by on the Y axis
*/
void smoothScrollTo(int x, int y) {
smoothScrollTo(x, y, 0);
}
/**
* Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
*
* @param x the number of pixels to scroll by on the X axis
* @param y the number of pixels to scroll by on the Y axis
* @param velocity the velocity associated with a fling, if applicable. (0 otherwise)
*/
void smoothScrollTo(int x, int y, int velocity) {
if (getChildCount() == 0) {
// Nothing to do.
setScrollingCacheEnabled(false);
return;
}
int sx = getScrollX();
int sy = getScrollY();
int dx = x - sx;
int dy = y - sy;
if (dx == 0 && dy == 0) {
completeScroll();
if (isMenuOpen()) {
if (mOpenedListener != null)
mOpenedListener.onOpened();
} else {
if (mClosedListener != null)
mClosedListener.onClosed();
}
return;
}
setScrollingCacheEnabled(true);
mScrolling = true;
final int width = getBehindWidth();
final int halfWidth = width / 2;
final float distanceRatio = Math.min(1f, 1.0f * Math.abs(dx) / width);
final float distance = halfWidth + halfWidth *
distanceInfluenceForSnapDuration(distanceRatio);
int duration = 0;
velocity = Math.abs(velocity);
if (velocity > 0) {
duration = 4 * Math.round(1000 * Math.abs(distance / velocity));
} else {
final float pageDelta = (float) Math.abs(dx) / width;
duration = (int) ((pageDelta + 1) * 100);
duration = MAX_SETTLE_DURATION;
}
duration = Math.min(duration, MAX_SETTLE_DURATION);
mScroller.startScroll(sx, sy, dx, dy, duration);
invalidate();
}
public void setContent(View v) {
if (mContent != null)
this.removeView(mContent);
mContent = v;
addView(mContent);
}
public View getContent() {
return mContent;
}
public void setCustomViewBehind(CustomViewBehind cvb) {
mViewBehind = cvb;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = getDefaultSize(0, widthMeasureSpec);
int height = getDefaultSize(0, heightMeasureSpec);
setMeasuredDimension(width, height);
final int contentWidth = getChildMeasureSpec(widthMeasureSpec, 0, width);
final int contentHeight = getChildMeasureSpec(heightMeasureSpec, 0, height);
mContent.measure(contentWidth, contentHeight);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// Make sure scroll position is set correctly.
if (w != oldw) {
// [ChrisJ] - This fixes the onConfiguration change for orientation issue..
// maybe worth having a look why the recomputeScroll pos is screwing
// up?
completeScroll();
scrollTo(getDestScrollX(mCurItem), getScrollY());
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
final int width = r - l;
final int height = b - t;
mContent.layout(0, 0, width, height);
}
public void setAboveOffset(int i) {
// RelativeLayout.LayoutParams params = ((RelativeLayout.LayoutParams)mContent.getLayoutParams());
// params.setMargins(i, params.topMargin, params.rightMargin, params.bottomMargin);
mContent.setPadding(i, mContent.getPaddingTop(),
mContent.getPaddingRight(), mContent.getPaddingBottom());
}
@Override
public void computeScroll() {
if (!mScroller.isFinished()) {
if (mScroller.computeScrollOffset()) {
int oldX = getScrollX();
int oldY = getScrollY();
int x = mScroller.getCurrX();
int y = mScroller.getCurrY();
if (oldX != x || oldY != y) {
scrollTo(x, y);
pageScrolled(x);
}
// Keep on drawing until the animation has finished.
invalidate();
return;
}
}
// Done with scroll, clean up state.
completeScroll();
}
private void pageScrolled(int xpos) {
final int widthWithMargin = getWidth();
final int position = xpos / widthWithMargin;
final int offsetPixels = xpos % widthWithMargin;
final float offset = (float) offsetPixels / widthWithMargin;
onPageScrolled(position, offset, offsetPixels);
}
/**
* This method will be invoked when the current page is scrolled, either as part
* of a programmatically initiated smooth scroll or a user initiated touch scroll.
* If you override this method you must call through to the superclass implementation
* (e.g. super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled
* returns.
*
* @param position Position index of the first page currently being displayed.
* Page position+1 will be visible if positionOffset is nonzero.
* @param offset Value from [0, 1) indicating the offset from the page at position.
* @param offsetPixels Value in pixels indicating the offset from position.
*/
protected void onPageScrolled(int position, float offset, int offsetPixels) {
if (mOnPageChangeListener != null) {
mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels);
}
if (mInternalPageChangeListener != null) {
mInternalPageChangeListener.onPageScrolled(position, offset, offsetPixels);
}
}
private void completeScroll() {
boolean needPopulate = mScrolling;
if (needPopulate) {
// Done with scroll, no longer want to cache view drawing.
setScrollingCacheEnabled(false);
mScroller.abortAnimation();
int oldX = getScrollX();
int oldY = getScrollY();
int x = mScroller.getCurrX();
int y = mScroller.getCurrY();
if (oldX != x || oldY != y) {
scrollTo(x, y);
}
if (isMenuOpen()) {
if (mOpenedListener != null)
mOpenedListener.onOpened();
} else {
if (mClosedListener != null)
mClosedListener.onClosed();
}
}
mScrolling = false;
}
protected int mTouchMode = SlidingMenu.TOUCHMODE_MARGIN;
public void setTouchMode(int i) {
mTouchMode = i;
}
public int getTouchMode() {
return mTouchMode;
}
private boolean thisTouchAllowed(MotionEvent ev) {
int x = (int) (ev.getX() + mScrollX);
if (isMenuOpen()) {
return mViewBehind.menuOpenTouchAllowed(mContent, mCurItem, x);
} else {
switch (mTouchMode) {
case SlidingMenu.TOUCHMODE_FULLSCREEN:
return !isInIgnoredView(ev);
case SlidingMenu.TOUCHMODE_NONE:
return false;
case SlidingMenu.TOUCHMODE_MARGIN:
return mViewBehind.marginTouchAllowed(mContent, x);
}
}
return false;
}
private boolean thisSlideAllowed(float dx) {
boolean allowed = false;
if (isMenuOpen()) {
allowed = mViewBehind.menuOpenSlideAllowed(dx);
} else {
allowed = mViewBehind.menuClosedSlideAllowed(dx);
}
if (DEBUG)
Log.v(TAG, "this slide allowed " + allowed + " dx: " + dx);
return allowed;
}
private int getPointerIndex(MotionEvent ev, int id) {
int activePointerIndex = MotionEventCompat.findPointerIndex(ev, id);
if (activePointerIndex == -1)
mActivePointerId = INVALID_POINTER;
return activePointerIndex;
}
private boolean mQuickReturn = false;
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (!mEnabled)
return false;
final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;
if (DEBUG)
if (action == MotionEvent.ACTION_DOWN)
Log.v(TAG, "Received ACTION_DOWN");
if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP
|| (action != MotionEvent.ACTION_DOWN && mIsUnableToDrag)) {
endDrag();
return false;
}
switch (action) {
case MotionEvent.ACTION_MOVE:
determineDrag(ev);
break;
case MotionEvent.ACTION_DOWN:
int index = MotionEventCompat.getActionIndex(ev);
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
if (mActivePointerId == INVALID_POINTER)
break;
mLastMotionX = mInitialMotionX = MotionEventCompat.getX(ev, index);
mLastMotionY = MotionEventCompat.getY(ev, index);
if (thisTouchAllowed(ev)) {
mIsBeingDragged = false;
mIsUnableToDrag = false;
if (isMenuOpen() && mViewBehind.menuTouchInQuickReturn(mContent, mCurItem, ev.getX() + mScrollX)) {
mQuickReturn = true;
}
} else {
mIsUnableToDrag = true;
}
break;
case MotionEventCompat.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
break;
}
if (!mIsBeingDragged) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
}
return mIsBeingDragged || mQuickReturn;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (!mEnabled)
return false;
if (!mIsBeingDragged && !thisTouchAllowed(ev))
return false;
// if (!mIsBeingDragged && !mQuickReturn)
// return false;
final int action = ev.getAction();
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
switch (action & MotionEventCompat.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
completeScroll();
// Remember where the motion event started
int index = MotionEventCompat.getActionIndex(ev);
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
mLastMotionX = mInitialMotionX = ev.getX();
break;
case MotionEvent.ACTION_MOVE:
if (!mIsBeingDragged) {
determineDrag(ev);
if (mIsUnableToDrag)
return false;
}
if (mIsBeingDragged) {
// Scroll to follow the motion event
final int activePointerIndex = getPointerIndex(ev, mActivePointerId);
if (mActivePointerId == INVALID_POINTER)
break;
final float x = MotionEventCompat.getX(ev, activePointerIndex);
final float deltaX = mLastMotionX - x;
mLastMotionX = x;
float oldScrollX = getScrollX();
float scrollX = oldScrollX + deltaX;
final float leftBound = getLeftBound();
final float rightBound = getRightBound();
if (scrollX < leftBound) {
scrollX = leftBound;
} else if (scrollX > rightBound) {
scrollX = rightBound;
}
// Don't lose the rounded component
mLastMotionX += scrollX - (int) scrollX;
scrollTo((int) scrollX, getScrollY());
pageScrolled((int) scrollX);
}
break;
case MotionEvent.ACTION_UP:
if (mIsBeingDragged) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int initialVelocity = (int) VelocityTrackerCompat.getXVelocity(
velocityTracker, mActivePointerId);
final int scrollX = getScrollX();
// final int widthWithMargin = getWidth();
// final float pageOffset = (float) (scrollX % widthWithMargin) / widthWithMargin;
// TODO test this. should get better flinging behavior
final float pageOffset = (float) (scrollX - getDestScrollX(mCurItem)) / getBehindWidth();
final int activePointerIndex = getPointerIndex(ev, mActivePointerId);
if (mActivePointerId != INVALID_POINTER) {
final float x = MotionEventCompat.getX(ev, activePointerIndex);
final int totalDelta = (int) (x - mInitialMotionX);
int nextPage = determineTargetPage(pageOffset, initialVelocity, totalDelta);
setCurrentItemInternal(nextPage, true, true, initialVelocity);
} else {
setCurrentItemInternal(mCurItem, true, true, initialVelocity);
}
mActivePointerId = INVALID_POINTER;
endDrag();
} else if (mQuickReturn && mViewBehind.menuTouchInQuickReturn(mContent, mCurItem, ev.getX() + mScrollX)) {
// close the menu
setCurrentItem(1);
endDrag();
}
break;
case MotionEvent.ACTION_CANCEL:
if (mIsBeingDragged) {
setCurrentItemInternal(mCurItem, true, true);
mActivePointerId = INVALID_POINTER;
endDrag();
}
break;
case MotionEventCompat.ACTION_POINTER_DOWN: {
final int indexx = MotionEventCompat.getActionIndex(ev);
mLastMotionX = MotionEventCompat.getX(ev, indexx);
mActivePointerId = MotionEventCompat.getPointerId(ev, indexx);
break;
}
case MotionEventCompat.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
int pointerIndex = getPointerIndex(ev, mActivePointerId);
if (mActivePointerId == INVALID_POINTER)
break;
mLastMotionX = MotionEventCompat.getX(ev, pointerIndex);
break;
}
return true;
}
private void determineDrag(MotionEvent ev) {
final int activePointerId = mActivePointerId;
final int pointerIndex = getPointerIndex(ev, activePointerId);
if (activePointerId == INVALID_POINTER)
return;
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float dx = x - mLastMotionX;
final float xDiff = Math.abs(dx);
final float y = MotionEventCompat.getY(ev, pointerIndex);
final float dy = y - mLastMotionY;
final float yDiff = Math.abs(dy);
if (xDiff > (isMenuOpen()?mTouchSlop/2:mTouchSlop) && xDiff > yDiff && thisSlideAllowed(dx)) {
startDrag();
mLastMotionX = x;
mLastMotionY = y;
setScrollingCacheEnabled(true);
// TODO add back in touch slop check
} else if (xDiff > mTouchSlop) {
mIsUnableToDrag = true;
}
}
@Override
public void scrollTo(int x, int y) {
super.scrollTo(x, y);
mScrollX = x;
mViewBehind.scrollBehindTo(mContent, x, y);
((SlidingMenu)getParent()).manageLayers(getPercentOpen());
}
private int determineTargetPage(float pageOffset, int velocity, int deltaX) {
int targetPage = mCurItem;
if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) {
if (velocity > 0 && deltaX > 0) {
targetPage -= 1;
} else if (velocity < 0 && deltaX < 0){
targetPage += 1;
}
} else {
targetPage = (int) Math.round(mCurItem + pageOffset);
}
return targetPage;
}
protected float getPercentOpen() {
return Math.abs(mScrollX-mContent.getLeft()) / getBehindWidth();
}
@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
// Draw the margin drawable if needed.
mViewBehind.drawShadow(mContent, canvas);
mViewBehind.drawFade(mContent, canvas, getPercentOpen());
mViewBehind.drawSelector(mContent, canvas, getPercentOpen());
}
// variables for drawing
private float mScrollX = 0.0f;
private void onSecondaryPointerUp(MotionEvent ev) {
if (DEBUG) Log.v(TAG, "onSecondaryPointerUp called");
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastMotionX = MotionEventCompat.getX(ev, newPointerIndex);
mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
if (mVelocityTracker != null) {
mVelocityTracker.clear();
}
}
}
private void startDrag() {
mIsBeingDragged = true;
mQuickReturn = false;
}
private void endDrag() {
mQuickReturn = false;
mIsBeingDragged = false;
mIsUnableToDrag = false;
mActivePointerId = INVALID_POINTER;
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
private void setScrollingCacheEnabled(boolean enabled) {
if (mScrollingCacheEnabled != enabled) {
mScrollingCacheEnabled = enabled;
if (USE_CACHE) {
final int size = getChildCount();
for (int i = 0; i < size; ++i) {
final View child = getChildAt(i);
if (child.getVisibility() != GONE) {
child.setDrawingCacheEnabled(enabled);
}
}
}
}
}
/**
* Tests scrollability within child views of v given a delta of dx.
*
* @param v View to test for horizontal scrollability
* @param checkV Whether the view v passed should itself be checked for scrollability (true),
* or just its children (false).
* @param dx Delta scrolled in pixels
* @param x X coordinate of the active touch point
* @param y Y coordinate of the active touch point
* @return true if child views of v can be scrolled by delta of dx.
*/
protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
if (v instanceof ViewGroup) {
final ViewGroup group = (ViewGroup) v;
final int scrollX = v.getScrollX();
final int scrollY = v.getScrollY();
final int count = group.getChildCount();
// Count backwards - let topmost views consume scroll distance first.
for (int i = count - 1; i >= 0; i--) {
final View child = group.getChildAt(i);
if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() &&
y + scrollY >= child.getTop() && y + scrollY < child.getBottom() &&
canScroll(child, true, dx, x + scrollX - child.getLeft(),
y + scrollY - child.getTop())) {
return true;
}
}
}
return checkV && ViewCompat.canScrollHorizontally(v, -dx);
}
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
// Let the focused view and/or our descendants get the key first
return super.dispatchKeyEvent(event) || executeKeyEvent(event);
}
/**
* You can call this function yourself to have the scroll view perform
* scrolling from a key event, just as if the event had been dispatched to
* it by the view hierarchy.
*
* @param event The key event to execute.
* @return Return true if the event was handled, else false.
*/
public boolean executeKeyEvent(KeyEvent event) {
boolean handled = false;
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (event.getKeyCode()) {
case KeyEvent.KEYCODE_DPAD_LEFT:
handled = arrowScroll(FOCUS_LEFT);
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
handled = arrowScroll(FOCUS_RIGHT);
break;
case KeyEvent.KEYCODE_TAB:
if (Build.VERSION.SDK_INT >= 11) {
// The focus finder had a bug handling FOCUS_FORWARD and FOCUS_BACKWARD
// before Android 3.0. Ignore the tab key on those devices.
if (KeyEventCompat.hasNoModifiers(event)) {
handled = arrowScroll(FOCUS_FORWARD);
} else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) {
handled = arrowScroll(FOCUS_BACKWARD);
}
}
break;
}
}
return handled;
}
public boolean arrowScroll(int direction) {
View currentFocused = findFocus();
if (currentFocused == this) currentFocused = null;
boolean handled = false;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused,
direction);
if (nextFocused != null && nextFocused != currentFocused) {
if (direction == View.FOCUS_LEFT) {
handled = nextFocused.requestFocus();
} else if (direction == View.FOCUS_RIGHT) {
// If there is nothing to the right, or this is causing us to
// jump to the left, then what we really want to do is page right.
if (currentFocused != null && nextFocused.getLeft() <= currentFocused.getLeft()) {
handled = pageRight();
} else {
handled = nextFocused.requestFocus();
}
}
} else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) {
// Trying to move left and nothing there; try to page.
handled = pageLeft();
} else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) {
// Trying to move right and nothing there; try to page.
handled = pageRight();
}
if (handled) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
}
return handled;
}
boolean pageLeft() {
if (mCurItem > 0) {
setCurrentItem(mCurItem-1, true);
return true;
}
return false;
}
boolean pageRight() {
if (mCurItem < 1) {
setCurrentItem(mCurItem+1, true);
return true;
}
return false;
}
}
</view></view>
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