技术标签： android 源码解读
首先调用
public void invalidate() {
invalidate(true);
}
调用invalidete 带参数的方法
void invalidate(boolean invalidateCache) {
invalidateInternal(0, 0, mRight - mLeft, mBottom - mTop, invalidateCache, true);
}
调用invalidateInternal方法
void invalidateInternal(int l, int t, int r, int b, boolean invalidateCache,
boolean fullInvalidate) {
if (mGhostView != null) {
mGhostView.invalidate(true);
return;
}
if (skipInvalidate()) {
return;
}
if ((mPrivateFlags & (PFLAG_DRAWN | PFLAG_HAS_BOUNDS)) == (PFLAG_DRAWN | PFLAG_HAS_BOUNDS)
|| (invalidateCache && (mPrivateFlags & PFLAG_DRAWING_CACHE_VALID) == PFLAG_DRAWING_CACHE_VALID)
|| (mPrivateFlags & PFLAG_INVALIDATED) != PFLAG_INVALIDATED
|| (fullInvalidate && isOpaque() != mLastIsOpaque)) {
if (fullInvalidate) {
mLastIsOpaque = isOpaque();
mPrivateFlags &= ~PFLAG_DRAWN;
}
mPrivateFlags |= PFLAG_DIRTY;
if (invalidateCache) {
mPrivateFlags |= PFLAG_INVALIDATED;
mPrivateFlags &= ~PFLAG_DRAWING_CACHE_VALID;
}
// Propagate the damage rectangle to the parent view.
final AttachInfo ai = mAttachInfo;
final ViewParent p = mParent;
if (p != null && ai != null && l < r && t < b) {
final Rect damage = ai.mTmpInvalRect;
damage.set(l, t, r, b);
p.invalidateChild(this, damage);
}
// Damage the entire projection receiver, if necessary.
if (mBackground != null && mBackground.isProjected()) {
final View receiver = getProjectionReceiver();
if (receiver != null) {
receiver.damageInParent();
}
}
// Damage the entire IsolatedZVolume receiving this view's shadow.
if (isHardwareAccelerated() && getZ() != 0) {
damageShadowReceiver();
}
}
}
invalidateInternal里面调用了ViewParent的invaludateChild方法，而ViewParent就是当前View的外层ViewGroup
查看ViewGroup的invaludateChild方法.这个方法里面有个while循环，一直向外层ViewGroup回调invaludateChildInParent方法。我们都知道最终顶层的View就是DecoView,而DecoView里面的ViewParent又是哪个呢？
public final void invalidateChild(View child, final Rect dirty) {
ViewParent parent = this;
final AttachInfo attachInfo = mAttachInfo;
//省略部分代码
//while循环，一直向上回调ViewGroup 的invalidateChildInParent
do {
View view = null;
if (parent instanceof View) {
view = (View) parent;
}
parent = parent.invalidateChildInParent(location, dirty);
if (view != null) {
// Account for transform on current parent
Matrix m = view.getMatrix();
if (!m.isIdentity()) {
RectF boundingRect = attachInfo.mTmpTransformRect;
boundingRect.set(dirty);
m.mapRect(boundingRect);
dirty.set((int) (boundingRect.left - 0.5f),
(int) (boundingRect.top - 0.5f),
(int) (boundingRect.right + 0.5f),
(int) (boundingRect.bottom + 0.5f));
}
}
} while (parent != null);
}
}
WindowManagerGlobal.java view为DecorView
当我们setContent方法后，在Activity 的onResume方法前，会把当前的顶层DecoView添加到addView 到WindowManager里面，而WindowManager的实现类WindowManagerImpl里面的调用的是WindowManagerGlobal的addView方法，如下。看注释的关系代码，这里实例化了一个ViewRootImpl,调用了setView方法，传入的view参数就是DecorView
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow)
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
//关键代码
root = new ViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
}
// do this last because it fires off messages to start doing things
try {
root.setView(view, wparams, panelParentView);
} catch (RuntimeException e) {
// BadTokenException or InvalidDisplayException, clean up.
synchronized (mLock) {
final int index = findViewLocked(view, false);
if (index >= 0) {
removeViewLocked(index, true);
}
}
throw e;
}
}
ViewRootImpl 的setView方法,其中view为DecorView,在该方法里面调用了view.assigenParent(this),把ViewRootImpl设置为DecorView的ViewParent.
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
synchronized (this) {
if (mView == null) {
mView = view;
mAttachInfo.mDisplayState = mDisplay.getState();
mDisplayManager.registerDisplayListener(mDisplayListener, mHandler);
CompatibilityInfo compatibilityInfo = mDisplayAdjustments.getCompatibilityInfo();
mTranslator = compatibilityInfo.getTranslator();
mAdded = true;
int res; /* = WindowManagerImpl.ADD_OKAY; */
// Schedule the first layout -before- adding to the window
// manager, to make sure we do the relayout before receiving
// any other events from the system.
requestLayout();
//关键代码.设置DecorView的viewParent为ViewRootImpl
view.assignParent(this);
mAddedTouchMode = (res & WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE) != 0;
mAppVisible = (res & WindowManagerGlobal.ADD_FLAG_APP_VISIBLE) != 0;
if (mAccessibilityManager.isEnabled()) {
mAccessibilityInteractionConnectionManager.ensureConnection();
}
if (view.getImportantForAccessibility() == View.IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
view.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
}
}
}
ViewGroup invalidateChild方法里面的while循环完最终调用ViewRootImpl里面的invaludateChild方法,查看ViewRootImpl里面的invalidateChild方法
ViewRootImpl
public void invalidateChild(View child, Rect dirty) {
invalidateChildInParent(null, dirty);
}
调用了invalidateChildInParent方法
@Override
public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
checkThread();
if (DEBUG_DRAW) Log.v(TAG, "Invalidate child: " + dirty);
if (dirty == null) {
invalidate();
return null;
} else if (dirty.isEmpty() && !mIsAnimating) {
return null;
}
if (mCurScrollY != 0 || mTranslator != null) {
mTempRect.set(dirty);
dirty = mTempRect;
if (mCurScrollY != 0) {
dirty.offset(0, -mCurScrollY);
}
if (mTranslator != null) {
mTranslator.translateRectInAppWindowToScreen(dirty);
}
if (mAttachInfo.mScalingRequired) {
dirty.inset(-1, -1);
}
}
invalidateRectOnScreen(dirty);
return null;
}
调用了invalidateRectOnScreen方法,由方法名可猜测该方法是刷新屏幕上面的一个Rect区域，而Rect区域就是调用invalidate方法的那个View大小
private void invalidateRectOnScreen(Rect dirty) {
final Rect localDirty = mDirty;
if (!localDirty.isEmpty() && !localDirty.contains(dirty)) {
mAttachInfo.mSetIgnoreDirtyState = true;
mAttachInfo.mIgnoreDirtyState = true;
}
// Add the new dirty rect to the current one
localDirty.union(dirty.left, dirty.top, dirty.right, dirty.bottom);
// Intersect with the bounds of the window to skip
// updates that lie outside of the visible region
final float appScale = mAttachInfo.mApplicationScale;
final boolean intersected = localDirty.intersect(0, 0,
(int) (mWidth * appScale + 0.5f), (int) (mHeight * appScale + 0.5f));
if (!intersected) {
localDirty.setEmpty();
}
if (!mWillDrawSoon && (intersected || mIsAnimating)) {
scheduleTraversals();
}
}
里面调用了scheduleTraversals方法，
scheduleTraversals方法里面发送了一个消息，将执行TraversalRunnable 任务方法
void scheduleTraversals() {
if (!mTraversalScheduled) {
mTraversalScheduled = true;
mTraversalBarrier = mHandler.getLooper().getQueue().postSyncBarrier();
mChoreographer.postCallback(
Choreographer.CALLBACK_TRAVERSAL, mTraversalRunnable, null);
if (!mUnbufferedInputDispatch) {
scheduleConsumeBatchedInput();
}
notifyRendererOfFramePending();
pokeDrawLockIfNeeded();
}
}
TraversalRunnable 任务方法
final class TraversalRunnable implements Runnable {
@Override
public void run() {
doTraversal();
}
}
这个方法又调用了performTraversals()
void doTraversal() {
if (mTraversalScheduled) {
mTraversalScheduled = false;
mHandler.getLooper().getQueue().removeSyncBarrier(mTraversalBarrier);
if (mProfile) {
Debug.startMethodTracing("ViewAncestor");
}
performTraversals();
if (mProfile) {
Debug.stopMethodTracing();
mProfile = false;
}
}
}
performTraversals这个方法挺长的，里面执行的方法也多。继续看
里面依次可能会调用了performMeasure，performLayout，performDraw。这三个和我们常用的onMeasure,onLayout,onDraw方法就很像了，因为这三个方法最终也会调用我们常用的onXXX方法。在这里这三个方法不一定都会调用，当我们调用invalidate的时候，也就是说我们只想调用绘制我们的View的方法，这个时候只会调用到performDraw方法,当我们的view如果位置发生改变了，则也会调用到performLayout方法，如果大小也改变了，则也会调用perforMeasure方法。这三个方法就会回调我们自己View里面的mesure,layout,draw方法，measure内部会回调onMeasure,layout内部会回调onLayout,draw内部会回调onDraw。追踪到这里就差不多了，因为最终会回调到那个invalidate方法的view的onDraw方法里去。
private void performTraversals() {
// cache mView since it is used so much below...
final View host = mView;
mIsInTraversal = true;
mWillDrawSoon = true;
boolean windowSizeMayChange = false;
boolean newSurface = false;
boolean surfaceChanged = false;
WindowManager.LayoutParams lp = mWindowAttributes;
int desiredWindowWidth;
int desiredWindowHeight;
final int viewVisibility = getHostVisibility();
boolean viewVisibilityChanged = mViewVisibility != viewVisibility
|| mNewSurfaceNeeded;
WindowManager.LayoutParams params = null;
if (mFirst) {
mFullRedrawNeeded = true;
mLayoutRequested = true;
if (lp.type == WindowManager.LayoutParams.TYPE_STATUS_BAR_PANEL
|| lp.type == WindowManager.LayoutParams.TYPE_INPUT_METHOD) {
// NOTE -- system code, won't try to do compat mode.
Point size = new Point();
mDisplay.getRealSize(size);
desiredWindowWidth = size.x;
desiredWindowHeight = size.y;
} else {
DisplayMetrics packageMetrics =
mView.getContext().getResources().getDisplayMetrics();
desiredWindowWidth = packageMetrics.widthPixels;
desiredWindowHeight = packageMetrics.heightPixels;
}
} else {
desiredWindowWidth = frame.width();
desiredWindowHeight = frame.height();
if (desiredWindowWidth != mWidth || desiredWindowHeight != mHeight) {
if (DEBUG_ORIENTATION) Log.v(TAG,
"View " + host + " resized to: " + frame);
mFullRedrawNeeded = true;
mLayoutRequested = true;
windowSizeMayChange = true;
}
}
boolean insetsChanged = false;
boolean layoutRequested = mLayoutRequested && (!mStopped || mReportNextDraw);
if (layoutRequested) {
final Resources res = mView.getContext().getResources();
if (mFirst) {
// make sure touch mode code executes by setting cached value
// to opposite of the added touch mode.
mAttachInfo.mInTouchMode = !mAddedTouchMode;
ensureTouchModeLocally(mAddedTouchMode);
} else {
if (!mPendingOverscanInsets.equals(mAttachInfo.mOverscanInsets)) {
insetsChanged = true;
}
if (!mPendingContentInsets.equals(mAttachInfo.mContentInsets)) {
insetsChanged = true;
}
if (!mPendingStableInsets.equals(mAttachInfo.mStableInsets)) {
insetsChanged = true;
}
if (!mPendingVisibleInsets.equals(mAttachInfo.mVisibleInsets)) {
mAttachInfo.mVisibleInsets.set(mPendingVisibleInsets);
if (DEBUG_LAYOUT) Log.v(TAG, "Visible insets changing to: "
+ mAttachInfo.mVisibleInsets);
}
if (!mPendingOutsets.equals(mAttachInfo.mOutsets)) {
insetsChanged = true;
}
}
// Determine whether to compute insets.
// If there are no inset listeners remaining then we may still need to compute
// insets in case the old insets were non-empty and must be reset.
final boolean computesInternalInsets =
mAttachInfo.mTreeObserver.hasComputeInternalInsetsListeners()
|| mAttachInfo.mHasNonEmptyGivenInternalInsets;
boolean insetsPending = false;
int relayoutResult = 0;
if (mSurfaceHolder != null) {
// The app owns the surface; tell it about what is going on.
if (mSurface.isValid()) {
// XXX .copyFrom() doesn't work!
//mSurfaceHolder.mSurface.copyFrom(mSurface);
mSurfaceHolder.mSurface = mSurface;
}
mSurfaceHolder.setSurfaceFrameSize(mWidth, mHeight);
mSurfaceHolder.mSurfaceLock.unlock();
if (mSurface.isValid()) {
if (!hadSurface) {
mSurfaceHolder.ungetCallbacks();
mIsCreating = true;
mSurfaceHolderCallback.surfaceCreated(mSurfaceHolder);
SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks();
if (callbacks != null) {
for (SurfaceHolder.Callback c : callbacks) {
c.surfaceCreated(mSurfaceHolder);
}
}
surfaceChanged = true;
}
if (surfaceChanged) {
mSurfaceHolderCallback.surfaceChanged(mSurfaceHolder,
lp.format, mWidth, mHeight);
SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks();
if (callbacks != null) {
for (SurfaceHolder.Callback c : callbacks) {
c.surfaceChanged(mSurfaceHolder, lp.format,
mWidth, mHeight);
}
}
}
mIsCreating = false;
} else if (hadSurface) {
mSurfaceHolder.ungetCallbacks();
SurfaceHolder.Callback callbacks[] = mSurfaceHolder.getCallbacks();
mSurfaceHolderCallback.surfaceDestroyed(mSurfaceHolder);
if (callbacks != null) {
for (SurfaceHolder.Callback c : callbacks) {
c.surfaceDestroyed(mSurfaceHolder);
}
}
mSurfaceHolder.mSurfaceLock.lock();
try {
mSurfaceHolder.mSurface = new Surface();
} finally {
mSurfaceHolder.mSurfaceLock.unlock();
}
}
}
// Ask host how big it wants to be
//会回调onMeasure方法
performMeasure(childWidthMeasureSpec, childHeightMeasureSpec);
// Implementation of weights from WindowManager.LayoutParams
// We just grow the dimensions as needed and re-measure if
// needs be
int width = host.getMeasuredWidth();
int height = host.getMeasuredHeight();
boolean measureAgain = false;
if (lp.horizontalWeight > 0.0f) {
width += (int) ((mWidth - width) * lp.horizontalWeight);
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(width,
MeasureSpec.EXACTLY);
measureAgain = true;
}
if (lp.verticalWeight > 0.0f) {
height += (int) ((mHeight - height) * lp.verticalWeight);
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height,
MeasureSpec.EXACTLY);
measureAgain = true;
}
if (measureAgain) {
if (DEBUG_LAYOUT) Log.v(TAG,
"And hey let's measure once more: width=" + width
+ " height=" + height);
performMeasure(childWidthMeasureSpec, childHeightMeasureSpec);
}
layoutRequested = true;
}
}
} else {
final boolean windowMoved = (mAttachInfo.mWindowLeft != frame.left
|| mAttachInfo.mWindowTop != frame.top);
if (windowMoved) {
if (mTranslator != null) {
mTranslator.translateRectInScreenToAppWinFrame(frame);
}
mAttachInfo.mWindowLeft = frame.left;
mAttachInfo.mWindowTop = frame.top;
// Update the light position for the new window offsets.
if (mAttachInfo.mHardwareRenderer != null) {
mAttachInfo.mHardwareRenderer.setLightCenter(mAttachInfo);
}
}
}
final boolean didLayout = layoutRequested && (!mStopped || mReportNextDraw);
boolean triggerGlobalLayoutListener = didLayout
|| mAttachInfo.mRecomputeGlobalAttributes;
if (didLayout) {
//会回调onLayout方法
performLayout(lp, desiredWindowWidth, desiredWindowHeight);
// By this point all views have been sized and positioned
// We can compute the transparent area
if ((host.mPrivateFlags & View.PFLAG_REQUEST_TRANSPARENT_REGIONS) != 0) {
// start out transparent
// TODO: AVOID THAT CALL BY CACHING THE RESULT?
host.getLocationInWindow(mTmpLocation);
mTransparentRegion.set(mTmpLocation[0], mTmpLocation[1],
mTmpLocation[0] + host.mRight - host.mLeft,
mTmpLocation[1] + host.mBottom - host.mTop);
host.gatherTransparentRegion(mTransparentRegion);
if (mTranslator != null) {
mTranslator.translateRegionInWindowToScreen(mTransparentRegion);
}
if (!mTransparentRegion.equals(mPreviousTransparentRegion)) {
mPreviousTransparentRegion.set(mTransparentRegion);
mFullRedrawNeeded = true;
// reconfigure window manager
try {
mWindowSession.setTransparentRegion(mWindow, mTransparentRegion);
} catch (RemoteException e) {
}
}
}
}
boolean skipDraw = false;
mFirst = false;
mWillDrawSoon = false;
mNewSurfaceNeeded = false;
mViewVisibility = viewVisibility;
// Remember if we must report the next draw.
if ((relayoutResult & WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) {
mReportNextDraw = true;
}
boolean cancelDraw = mAttachInfo.mTreeObserver.dispatchOnPreDraw() ||
viewVisibility != View.VISIBLE;
if (!cancelDraw && !newSurface) {
if (!skipDraw || mReportNextDraw) {
if (mPendingTransitions != null && mPendingTransitions.size() > 0) {
for (int i = 0; i < mPendingTransitions.size(); ++i) {
mPendingTransitions.get(i).startChangingAnimations();
}
mPendingTransitions.clear();
}
//会回调onDraw()方法
performDraw();
}
} else {
if (viewVisibility == View.VISIBLE) {
// Try again
scheduleTraversals();
} else if (mPendingTransitions != null && mPendingTransitions.size() > 0) {
for (int i = 0; i < mPendingTransitions.size(); ++i) {
mPendingTransitions.get(i).endChangingAnimations();
}
mPendingTransitions.clear();
}
}
mIsInTraversal = false;
}
至此流程梳理完毕
总结一下,调用View invalidate方法->View invalidateInternal 方法->ViewGroup 的invalidateChild方法->ViewRootImpl的invalidateChild---->performTraversals->View onDraw，大概主要调用流程如此，
文章浏览阅读1k次。通过使用ajax方法跨域请求是浏览器所不允许的，浏览器出于安全考虑是禁止的。警告信息如下：不过jQuery对跨域问题也有解决方案，使用jsonp的方式解决，方法如下：$.ajax({ async:false, url: 'http://www.mysite.com/demo.do', // 跨域URL ty..._nginx不停的xhr
文章浏览阅读2k次。关于在 Oracle 中配置 extproc 以访问 ST_Geometry，也就是我们所说的 使用空间SQL 的方法，官方文档链接如下。http://desktop.arcgis.com/zh-cn/arcmap/latest/manage-data/gdbs-in-oracle/configure-oracle-extproc.htm其实简单总结一下，主要就分为以下几个步骤。..._extproc
文章浏览阅读1.5w次。linux下没有上面的两个函数，需要使用函数 mbstowcs和wcstombsmbstowcs将多字节编码转换为宽字节编码wcstombs将宽字节编码转换为多字节编码这两个函数，转换过程中受到系统编码类型的影响，需要通过设置来设定转换前和转换后的编码类型。通过函数setlocale进行系统编码的设置。linux下输入命名locale -a查看系统支持的编码_linux c++ gbk->utf8
文章浏览阅读750次。今天准备从生产库向测试库进行数据导入，结果在imp导入的时候遇到“ IMP-00009:导出文件异常结束” 错误，google一下，发现可能有如下原因导致imp的数据太大，没有写buffer和commit两个数据库字符集不同从低版本exp的dmp文件，向高版本imp导出的dmp文件出错传输dmp文件时，文件损坏解决办法：imp时指定..._imp-00009导出文件异常结束
文章浏览阅读143次。当下是一个大数据的时代，各个行业都离不开数据的支持。因此，网络爬虫就应运而生。网络爬虫当下最为火热的是Python，Python开发爬虫相对简单，而且功能库相当完善，力压众多开发语言。本次教程我们爬取前程无忧的招聘信息来分析Python程序员需要掌握那些编程技术。首先在谷歌浏览器打开前程无忧的首页，按F12打开浏览器的开发者工具。浏览器开发者工具是用于捕捉网站的请求信息，通过分析请求信息可以了解请..._初级python程序员能力要求
文章浏览阅读7.6k次，点赞2次，收藏6次。@Service标注的bean，类名：ABDemoService查看源码后发现，原来是经过一个特殊处理：当类的名字是以两个或以上的大写字母开头的话，bean的名字会与类名保持一致public class AnnotationBeanNameGenerator implements BeanNameGenerator { private static final String C..._@service beanname
文章浏览阅读6.9w次，点赞73次，收藏463次。1.前序创建#include<stdio.h>#include<string.h>#include<stdlib.h>#include<malloc.h>#include<iostream>#include<stack>#include<queue>using namespace std;typed_二叉树的建立
文章浏览阅读7.1k次。在Asp.net上使用Excel导出功能，如果文件名出现中文，便会以乱码视之。 解决方法： fileName = HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8);_asp.net utf8 导出中文字符乱码
文章浏览阅读2.1k次，点赞4次，收藏23次。第一次实验 词法分析实验报告设计思想词法分析的主要任务是根据文法的词汇表以及对应约定的编码进行一定的识别，找出文件中所有的合法的单词，并给出一定的信息作为最后的结果，用于后续语法分析程序的使用；本实验针对 PL/0 语言 的文法、词汇表编写一个词法分析程序，对于每个单词根据词汇表输出： (单词种类, 单词的值) 二元对。词汇表：种别编码单词符号助记符0beginb..._对pl/0作以下修改扩充。增加单词
文章浏览阅读773次。我在使用adb.exe时遇到了麻烦.我想使用与bash相同的adb.exe shell提示符,所以我决定更改默认的bash二进制文件(当然二进制文件是交叉编译的,一切都很完美)更改bash二进制文件遵循以下顺序> adb remount> adb push bash / system / bin /> adb shell> cd / system / bin> chm..._adb shell mv 权限
文章浏览阅读6.8k次，点赞12次，收藏125次。1. 单目相机标定引言相机标定已经研究多年，标定的算法可以分为基于摄影测量的标定和自标定。其中，应用最为广泛的还是张正友标定法。这是一种简单灵活、高鲁棒性、低成本的相机标定算法。仅需要一台相机和一块平面标定板构建相机标定系统，在标定过程中，相机拍摄多个角度下（至少两个角度，推荐10~20个角度）的标定板图像（相机和标定板都可以移动），即可对相机的内外参数进行标定。下面介绍张氏标定法（以下也这么称呼）的原理。原理相机模型和单应矩阵相机标定，就是对相机的内外参数进行计算的过程，从而得到物体到图像的投影_相机-投影仪标定
文章浏览阅读2.2k次。文章目录Wayland 架构Wayland 渲染Wayland的 硬件支持简 述： 翻译一篇关于和 wayland 有关的技术文章, 其英文标题为Wayland Architecture .Wayland 架构若是想要更好的理解 Wayland 架构及其与 X (X11 or X Window System) 结构；一种很好的方法是将事件从输入设备就开始跟踪, 查看期间所有的屏幕上出现的变化。这就是我们现在对 X 的理解。 内核是从一个输入设备中获取一个事件，并通过 evdev 输入_wayland