源碼基于 Android 11 Api 30
LayoutInflater 簡介
- android.view.LayoutInflater
- 布局解析器
- 是一個抽象類
- 是一個系統服務，服務名稱是 Context.LAYOUT_INFLATER_SERVICE = “layout_inflater”
擷取 LayoutInflater 方式
1 Context#getSystemService
2 LayoutInflater#from
public static LayoutInflater from(Context context) {
//就是調用了 Context#getSystemService
LayoutInflater LayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//做了判空
if (LayoutInflater == null) {
throw new AssertionError("LayoutInflater not found.");
}
return LayoutInflater;
}
3 Activity#getLayoutInflater
private Window mWindow;
public Window getWindow() {
return mWindow;
}
@NonNull
public LayoutInflater getLayoutInflater() {
//PhoneWindow 是 mWindow 的唯一繼承實作類
return getWindow().getLayoutInflater();
}
- PhoneWindow#getLayoutInflater
private LayoutInflater mLayoutInflater; public PhoneWindow(Context context) { super(context); //就是調用了 LayoutInflater#from mLayoutInflater = LayoutInflater.from(context); mRenderShadowsInCompositor = Settings.Global.getInt(context.getContentResolver(), DEVELOPMENT_RENDER_SHADOWS_IN_COMPOSITOR, 1) != 0; } @Override public LayoutInflater getLayoutInflater() { return mLayoutInflater; }
inflate 方法
1 View#inflate
public static View inflate(Context context, @LayoutRes int resource, ViewGroup root) {
LayoutInflater factory = LayoutInflater.from(context);
return factory.inflate(resource, root);
}
- 其實就是調用了 LayoutInflater.from(context).inflate(resource, root) 方法
- 解析布局生成 View 加入 ViewGroup 裡面
2 LayoutInflater#inflate
- Android 内置了 org.xmlpull 元件，以 pull 方式處理 xml
public View inflate(@LayoutRes int resource, @Nullable ViewGroup root) {
return inflate(resource, root, root != null);
}
public View inflate(@LayoutRes int resource, @Nullable ViewGroup root, boolean attachToRoot) {
final Resources res = getContext().getResources();
if (DEBUG) {
Log.d(TAG, "INFLATING from resource: \"" + res.getResourceName(resource) + "\" ("
+ Integer.toHexString(resource) + ")");
}
View view = tryInflatePrecompiled(resource, res, root, attachToRoot);
if (view != null) {
return view;
}
//XmlBlock#newParser 建立 XmlBlock$Parser 傳回
XmlResourceParser parser = res.getLayout(resource);
try {
return inflate(parser, root, attachToRoot);
} finally {
parser.close();
}
}
//org.xmlpull.v1.XmlPullParser
public View inflate(XmlPullParser parser, @Nullable ViewGroup root) {
return inflate(parser, root, root != null);
}
//org.xmlpull.v1.XmlPullParser
public View inflate(XmlPullParser parser, @Nullable ViewGroup root, boolean attachToRoot) {
synchronized (mConstructorArgs) {
Trace.traceBegin(Trace.TRACE_TAG_VIEW, "inflate");
final Context inflaterContext = mContext;
final AttributeSet attrs = Xml.asAttributeSet(parser);
Context lastContext = (Context) mConstructorArgs[0];
mConstructorArgs[0] = inflaterContext;
//預設是傳入的 root
View result = root;
try {
//移動到開始标簽
advanceToRootNode(parser);
//如 androidx.constraintlayout.widget.ConstraintLayout
final String name = parser.getName();
if (DEBUG) {
System.out.println("**************************");
System.out.println("Creating root view: "
+ name);
System.out.println("**************************");
}
//根布局是 merge ，意味着必須要有父容器，是以下面判斷不滿足條件就抛異常
if (TAG_MERGE.equals(name)) {
if (root == null || !attachToRoot) {
throw new InflateException("<merge /> can be used only with a valid "
+ "ViewGroup root and attachToRoot=true");
}
//
rInflate(parser, root, inflaterContext, attrs, false);
} else {
// Temp is the root view that was found in the xml
final View temp = createViewFromTag(root, name, inflaterContext, attrs);
ViewGroup.LayoutParams params = null;
if (root != null) {
if (DEBUG) {
System.out.println("Creating params from root: " +
root);
}
// Create layout params that match root, if supplied
// new LayoutParams(getContext(), attrs)
params = root.generateLayoutParams(attrs);
if (!attachToRoot) {
// Set the layout params for temp if we are not
// attaching. (If we are, we use addView, below)
temp.setLayoutParams(params);
}
}
if (DEBUG) {
System.out.println("-----> start inflating children");
}
//遞歸解析 xml 布局中的子 View
// Inflate all children under temp against its context.
rInflateChildren(parser, temp, attrs, true);
if (DEBUG) {
System.out.println("-----> done inflating children");
}
// We are supposed to attach all the views we found (int temp)
// to root. Do that now.
if (root != null && attachToRoot) {
root.addView(temp, params);
}
// Decide whether to return the root that was passed in or the
// top view found in xml.
if (root == null || !attachToRoot) {
result = temp;
}
}
} catch (XmlPullParserException e) {
final InflateException ie = new InflateException(e.getMessage(), e);
ie.setStackTrace(EMPTY_STACK_TRACE);
throw ie;
} catch (Exception e) {
final InflateException ie = new InflateException(
getParserStateDescription(inflaterContext, attrs)
+ ": " + e.getMessage(), e);
ie.setStackTrace(EMPTY_STACK_TRACE);
throw ie;
} finally {
// Don't retain static reference on context.
mConstructorArgs[0] = lastContext;
mConstructorArgs[1] = null;
Trace.traceEnd(Trace.TRACE_TAG_VIEW);
}
//
return result;
}
}
- root == null || attachToRoot == false 傳回 xml 解析出的 temp 視圖
- root != null && attachToRoot == true 傳回傳入的 root 視圖，進行了 root.addView(temp, params) ，addView 方法裡進行了 temp .setLayoutParams(params)
- root != null && attachToRoot == false 時 xml 解析出的 temp 視圖 ，此時需要 temp .setLayoutParams(params)
由此可以得出當 root 為空時，xml 最外層布局的屬性會失效，因為壓根沒有設定參數嘛！
tryInflatePrecompiled
- Android 10 Api 29 新增特征，暫不深究
- 采用預編譯方式減少 xml 解析時間
private @Nullable
View tryInflatePrecompiled(@LayoutRes int resource, Resources res, @Nullable ViewGroup root,
boolean attachToRoot) {
if (!mUseCompiledView) {
//不使用預編譯，直接傳回 null
return null;
}
Trace.traceBegin(Trace.TRACE_TAG_VIEW, "inflate (precompiled)");
// Try to inflate using a precompiled layout.
//包名，如 com.louisgeek.xxx
String pkg = res.getResourcePackageName(resource);
//layout名稱，如 activity_main
String layout = res.getResourceEntryName(resource);
//通過反射建立對應的 View
try {
Class clazz = Class.forName("" + pkg + ".CompiledView", false, mPrecompiledClassLoader);
Method inflater = clazz.getMethod(layout, Context.class, int.class);
View view = (View) inflater.invoke(null, mContext, resource);
if (view != null && root != null) {
//解析屬性資訊設定到上面生成的 view 上
// We were able to use the precompiled inflater, but now we need to do some work to
// attach the view to the root correctly.
XmlResourceParser parser = res.getLayout(resource);
try {
AttributeSet attrs = Xml.asAttributeSet(parser);
advanceToRootNode(parser);
ViewGroup.LayoutParams params = root.generateLayoutParams(attrs);
//是否添加到 root，以及設定布局參數
if (attachToRoot) {
root.addView(view, params);
} else {
view.setLayoutParams(params);
}
} finally {
parser.close();
}
}
return view;
} catch (Throwable e) {
if (DEBUG) {
Log.e(TAG, "Failed to use precompiled view", e);
}
} finally {
Trace.traceEnd(Trace.TRACE_TAG_VIEW);
}
return null;
}
- mUseCompiledView = true 的情況，現僅供内部測試使用
protected LayoutInflater(Context context) { mContext = context; //無參方法預設 mUseCompiledView = false initPrecompiledViews(); } protected LayoutInflater(LayoutInflater original, Context newContext) { mContext = newContext; mFactory = original.mFactory; mFactory2 = original.mFactory2; mPrivateFactory = original.mPrivateFactory; setFilter(original.mFilter); //無參方法預設 mUseCompiledView = false initPrecompiledViews(); } /** * @hide for use by CTS tests */ @TestApi public void setPrecompiledLayoutsEnabledForTesting(boolean enablePrecompiledLayouts) { initPrecompiledViews(enablePrecompiledLayouts); } //無參方法預設 mUseCompiledView = false private void initPrecompiledViews() { // Precompiled layouts are not supported in this release. boolean enabled = false; initPrecompiledViews(enabled); } private void initPrecompiledViews(boolean enablePrecompiledViews) { mUseCompiledView = enablePrecompiledViews; if (!mUseCompiledView) { mPrecompiledClassLoader = null; return; } // Make sure the application allows code generation ApplicationInfo appInfo = mContext.getApplicationInfo(); if (appInfo.isEmbeddedDexUsed() || appInfo.isPrivilegedApp()) { mUseCompiledView = false; return; } // Try to load the precompiled layout file. try { mPrecompiledClassLoader = mContext.getClassLoader(); String dexFile = mContext.getCodeCacheDir() + COMPILED_VIEW_DEX_FILE_NAME; if (new File(dexFile).exists()) { mPrecompiledClassLoader = new PathClassLoader(dexFile, mPrecompiledClassLoader); } else { // If the precompiled layout file doesn't exist, then disable precompiled // layouts. mUseCompiledView = false; } } catch (Throwable e) { if (DEBUG) { Log.e(TAG, "Failed to initialized precompiled views layouts", e); } mUseCompiledView = false; } if (!mUseCompiledView) { mPrecompiledClassLoader = null; } }
XmlResourceParser
XmlBlock$Parser 、BridgeXmlBlockParser 實作了 XmlResourceParser 接口
- Resources#getLayout
@NonNull
public XmlResourceParser getLayout(@LayoutRes int id) throws NotFoundException {
return loadXmlResourceParser(id, "layout");
}
@NonNull
XmlResourceParser loadXmlResourceParser(@AnyRes int id, @NonNull String type)
throws NotFoundException {
//擷取臨時 TypedValue，内部有緩存機制
final TypedValue value = obtainTempTypedValue();
try {
final ResourcesImpl impl = mResourcesImpl;
impl.getValue(id, value, true);
if (value.type == TypedValue.TYPE_STRING) {
//
return loadXmlResourceParser(value.string.toString(), id,
value.assetCookie, type);
}
throw new NotFoundException("Resource ID #0x" + Integer.toHexString(id)
+ " type #0x" + Integer.toHexString(value.type) + " is not valid");
} finally {
releaseTempTypedValue(value);
}
}
@NonNull
XmlResourceParser loadXmlResourceParser(String file, int id, int assetCookie,
String type) throws NotFoundException {
return mResourcesImpl.loadXmlResourceParser(file, id, assetCookie, type);
}
- 使用 XmlPullParser 周遊 xml 檔案内的所有節點
AttributeSet
- Xml#asAttributeSet
public static AttributeSet asAttributeSet(XmlPullParser parser) {
//parser is XmlPullParser
//parser is XmlResourceParser
//XmlBlock$Parser implements XmlResourceParser
return (parser instanceof AttributeSet)
? (AttributeSet) parser
: new XmlPullAttributes(parser);
}
advanceToRootNode
- 通過 parser.next() 移動
private void advanceToRootNode(XmlPullParser parser)
throws InflateException, IOException, XmlPullParserException {
// Look for the root node.
int type;
while ((type = parser.next()) != XmlPullParser.START_TAG &&
type != XmlPullParser.END_DOCUMENT) {
// Empty
}
if (type != XmlPullParser.START_TAG) {
throw new InflateException(parser.getPositionDescription()
+ ": No start tag found!");
}
}
rInflate
- XmlPullParser.START_DOCUMENT 文檔開始标記，代表未讀取任何内容
- XmlPullParser.END_DOCUMENT 文檔結束标記
- XmlPullParser.START_TAG 開始标簽
- XmlPullParser.END_TAG 結束标簽
- XmlPullParser.TEXT 文本
void rInflate(XmlPullParser parser, View parent, Context context,
AttributeSet attrs, boolean finishInflate) throws XmlPullParserException, IOException {
//xml 的深度
final int depth = parser.getDepth();
int type;
boolean pendingRequestFocus = false;
while (
(
(type = parser.next()) != XmlPullParser.END_TAG
|| parser.getDepth() > depth
)
&& type != XmlPullParser.END_DOCUMENT
) {
if (type != XmlPullParser.START_TAG) {
continue;
}
//如 TextView
final String name = parser.getName();
if (TAG_REQUEST_FOCUS.equals(name)) {
//判斷 <requestFocus />
pendingRequestFocus = true;
consumeChildElements(parser);
} else if (TAG_TAG.equals(name)) {
//判斷 <tag />
parseViewTag(parser, parent, attrs);
} else if (TAG_INCLUDE.equals(name)) {
//判斷 <include />
if (parser.getDepth() == 0) {
throw new InflateException("<include /> cannot be the root element");
}
parseInclude(parser, context, parent, attrs);
} else if (TAG_MERGE.equals(name)) {
//判斷 <merge />
throw new InflateException("<merge /> must be the root element");
} else {
final View view = createViewFromTag(parent, name, context, attrs);
final ViewGroup viewGroup = (ViewGroup) parent;
final ViewGroup.LayoutParams params = viewGroup.generateLayoutParams(attrs);
//
rInflateChildren(parser, view, attrs, true);
viewGroup.addView(view, params);
}
}
if (pendingRequestFocus) {
parent.restoreDefaultFocus();
}
if (finishInflate) {
parent.onFinishInflate();
}
}
createViewFromTag
private View createViewFromTag(View parent, String name, Context context, AttributeSet attrs) {
return createViewFromTag(parent, name, context, attrs, false);
}
View createViewFromTag(View parent, String name, Context context, AttributeSet attrs,
boolean ignoreThemeAttr) {
if (name.equals("view")) {
name = attrs.getAttributeValue(null, "class");
}
// Apply a theme wrapper, if allowed and one is specified.
if (!ignoreThemeAttr) {
final TypedArray ta = context.obtainStyledAttributes(attrs, ATTRS_THEME);
final int themeResId = ta.getResourceId(0, 0);
if (themeResId != 0) {
context = new ContextThemeWrapper(context, themeResId);
}
ta.recycle();
}
try {
//通過 LayoutInflater$Factory2、LayoutInflater$Factory 執行 onCreateView 方法
View view = tryCreateView(parent, name, context, attrs);
if (view == null) {
final Object lastContext = mConstructorArgs[0];
mConstructorArgs[0] = context;
try {
if (-1 == name.indexOf('.')) {
view = onCreateView(context, parent, name, attrs);
} else {
view = createView(context, name, null, attrs);
}
} finally {
mConstructorArgs[0] = lastContext;
}
}
return view;
} catch (InflateException e) {
throw e;
} catch (ClassNotFoundException e) {
final InflateException ie = new InflateException(
getParserStateDescription(context, attrs)
+ ": Error inflating class " + name, e);
ie.setStackTrace(EMPTY_STACK_TRACE);
throw ie;
} catch (Exception e) {
final InflateException ie = new InflateException(
getParserStateDescription(context, attrs)
+ ": Error inflating class " + name, e);
ie.setStackTrace(EMPTY_STACK_TRACE);
throw ie;
}
}
- LayoutInflater#tryCreateView
@Nullable public final View tryCreateView(@Nullable View parent, @NonNull String name, @NonNull Context context, @NonNull AttributeSet attrs) { if (name.equals(TAG_1995)) { // Let's party like it's 1995! return new BlinkLayout(context, attrs); } View view; if (mFactory2 != null) { view = mFactory2.onCreateView(parent, name, context, attrs); } else if (mFactory != null) { view = mFactory.onCreateView(name, context, attrs); } else { view = null; } if (view == null && mPrivateFactory != null) { view = mPrivateFactory.onCreateView(parent, name, context, attrs); } return view; } - LayoutInflater#onCreateView
@Nullable public View onCreateView(@NonNull Context viewContext, @Nullable View parent, @NonNull String name, @Nullable AttributeSet attrs) throws ClassNotFoundException { return onCreateView(parent, name, attrs); } protected View onCreateView(View parent, String name, AttributeSet attrs) throws ClassNotFoundException { return onCreateView(name, attrs); } protected View onCreateView(String name, AttributeSet attrs) throws ClassNotFoundException { return createView(name, "android.view.", attrs); } - LayoutInflater#createView
public final View createView(String name, String prefix, AttributeSet attrs) throws ClassNotFoundException, InflateException { Context context = (Context) mConstructorArgs[0]; if (context == null) { context = mContext; } return createView(context, name, prefix, attrs); } @Nullable public final View createView(@NonNull Context viewContext, @NonNull String name, @Nullable String prefix, @Nullable AttributeSet attrs) throws ClassNotFoundException, InflateException { Objects.requireNonNull(viewContext); Objects.requireNonNull(name); Constructor<? extends View> constructor = sConstructorMap.get(name); if (constructor != null && !verifyClassLoader(constructor)) { constructor = null; sConstructorMap.remove(name); } Class<? extends View> clazz = null; try { Trace.traceBegin(Trace.TRACE_TAG_VIEW, name); if (constructor == null) { // Class not found in the cache, see if it's real, and try to add it clazz = Class.forName(prefix != null ? (prefix + name) : name, false, mContext.getClassLoader()).asSubclass(View.class); if (mFilter != null && clazz != null) { boolean allowed = mFilter.onLoadClass(clazz); if (!allowed) { failNotAllowed(name, prefix, viewContext, attrs); } } constructor = clazz.getConstructor(mConstructorSignature); constructor.setAccessible(true); sConstructorMap.put(name, constructor); } else { // If we have a filter, apply it to cached constructor if (mFilter != null) { // Have we seen this name before? Boolean allowedState = mFilterMap.get(name); if (allowedState == null) { // New class -- remember whether it is allowed clazz = Class.forName(prefix != null ? (prefix + name) : name, false, mContext.getClassLoader()).asSubclass(View.class); boolean allowed = clazz != null && mFilter.onLoadClass(clazz); mFilterMap.put(name, allowed); if (!allowed) { failNotAllowed(name, prefix, viewContext, attrs); } } else if (allowedState.equals(Boolean.FALSE)) { failNotAllowed(name, prefix, viewContext, attrs); } } } Object lastContext = mConstructorArgs[0]; mConstructorArgs[0] = viewContext; Object[] args = mConstructorArgs; args[1] = attrs; try { final View view = constructor.newInstance(args); if (view instanceof ViewStub) { // Use the same context when inflating ViewStub later. final ViewStub viewStub = (ViewStub) view; viewStub.setLayoutInflater(cloneInContext((Context) args[0])); } return view; } finally { mConstructorArgs[0] = lastContext; } } catch (NoSuchMethodException e) { final InflateException ie = new InflateException( getParserStateDescription(viewContext, attrs) + ": Error inflating class " + (prefix != null ? (prefix + name) : name), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } catch (ClassCastException e) { // If loaded class is not a View subclass final InflateException ie = new InflateException( getParserStateDescription(viewContext, attrs) + ": Class is not a View " + (prefix != null ? (prefix + name) : name), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } catch (ClassNotFoundException e) { // If loadClass fails, we should propagate the exception. throw e; } catch (Exception e) { final InflateException ie = new InflateException( getParserStateDescription(viewContext, attrs) + ": Error inflating class " + (clazz == null ? "<unknown>" : clazz.getName()), e); ie.setStackTrace(EMPTY_STACK_TRACE); throw ie; } finally { Trace.traceEnd(Trace.TRACE_TAG_VIEW); } }
rInflateChildren
final void rInflateChildren(XmlPullParser parser, View parent, AttributeSet attrs,
boolean finishInflate) throws XmlPullParserException, IOException {
rInflate(parser, parent, parent.getContext(), attrs, finishInflate);
}
View.inflate 注意事項
- root == null 成立，那麼 attachToRoot = false
- root != null 成立，那麼 attachToRoot = true
是以不适合在清單的 Adapter 裡使用，因為它會自己添加 child view ，做不到 root !=null 同時 attachToRoot = false 的情況
是以也不合适在 Fragment#onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) 方法裡使用，因為 FragmentManager 裡會進行執行一次 container.addView
AppCompatDelegateImpl#onCreateView
@Override
public final View onCreateView(View parent, String name, Context context, AttributeSet attrs) {
return createView(parent, name, context, attrs);
}
@Override
public View createView(View parent, final String name, @NonNull Context context,
@NonNull AttributeSet attrs) {
if (mAppCompatViewInflater == null) {
TypedArray a = mContext.obtainStyledAttributes(R.styleable.AppCompatTheme);
String viewInflaterClassName =
a.getString(R.styleable.AppCompatTheme_viewInflaterClass);
if (viewInflaterClassName == null) {
// Set to null (the default in all AppCompat themes). Create the base inflater
// (no reflection)
mAppCompatViewInflater = new AppCompatViewInflater();
} else {
try {
Class<?> viewInflaterClass = Class.forName(viewInflaterClassName);
mAppCompatViewInflater =
(AppCompatViewInflater) viewInflaterClass.getDeclaredConstructor()
.newInstance();
} catch (Throwable t) {
Log.i(TAG, "Failed to instantiate custom view inflater "
+ viewInflaterClassName + ". Falling back to default.", t);
mAppCompatViewInflater = new AppCompatViewInflater();
}
}
}
boolean inheritContext = false;
if (IS_PRE_LOLLIPOP) {
inheritContext = (attrs instanceof XmlPullParser)
// If we have a XmlPullParser, we can detect where we are in the layout
? ((XmlPullParser) attrs).getDepth() > 1
// Otherwise we have to use the old heuristic
: shouldInheritContext((ViewParent) parent);
}
//createView
return mAppCompatViewInflater.createView(parent, name, context, attrs, inheritContext,
IS_PRE_LOLLIPOP, /* Only read android:theme pre-L (L+ handles this anyway) */
true, /* Read read app:theme as a fallback at all times for legacy reasons */
VectorEnabledTintResources.shouldBeUsed() /* Only tint wrap the context if enabled */
);
}
AppCompatViewInflater#createView
final View createView(View parent, final String name, @NonNull Context context,
@NonNull AttributeSet attrs, boolean inheritContext,
boolean readAndroidTheme, boolean readAppTheme, boolean wrapContext) {
final Context originalContext = context;
// We can emulate Lollipop's android:theme attribute propagating down the view hierarchy
// by using the parent's context
if (inheritContext && parent != null) {
context = parent.getContext();
}
if (readAndroidTheme || readAppTheme) {
// We then apply the theme on the context, if specified
context = themifyContext(context, attrs, readAndroidTheme, readAppTheme);
}
if (wrapContext) {
context = TintContextWrapper.wrap(context);
}
View view = null;
// We need to 'inject' our tint aware Views in place of the standard framework versions
switch (name) {
case "TextView":
view = createTextView(context, attrs);
verifyNotNull(view, name);
break;
case "ImageView":
view = createImageView(context, attrs);
verifyNotNull(view, name);
break;
case "Button":
view = createButton(context, attrs);
verifyNotNull(view, name);
break;
case "EditText":
view = createEditText(context, attrs);
verifyNotNull(view, name);
break;
case "Spinner":
view = createSpinner(context, attrs);
verifyNotNull(view, name);
break;
case "ImageButton":
view = createImageButton(context, attrs);
verifyNotNull(view, name);
break;
case "CheckBox":
view = createCheckBox(context, attrs);
verifyNotNull(view, name);
break;
case "RadioButton":
view = createRadioButton(context, attrs);
verifyNotNull(view, name);
break;
case "CheckedTextView":
view = createCheckedTextView(context, attrs);
verifyNotNull(view, name);
break;
case "AutoCompleteTextView":
view = createAutoCompleteTextView(context, attrs);
verifyNotNull(view, name);
break;
case "MultiAutoCompleteTextView":
view = createMultiAutoCompleteTextView(context, attrs);
verifyNotNull(view, name);
break;
case "RatingBar":
view = createRatingBar(context, attrs);
verifyNotNull(view, name);
break;
case "SeekBar":
view = createSeekBar(context, attrs);
verifyNotNull(view, name);
break;
case "ToggleButton":
view = createToggleButton(context, attrs);
verifyNotNull(view, name);
break;
default:
// The fallback that allows extending class to take over view inflation
// for other tags. Note that we don't check that the result is not-null.
// That allows the custom inflater path to fall back on the default one
// later in this method.
view = createView(context, name, attrs);
}
if (view == null && originalContext != context) {
// If the original context does not equal our themed context, then we need to manually
// inflate it using the name so that android:theme takes effect.
view = createViewFromTag(context, name, attrs);
}
if (view != null) {
// If we have created a view, check its android:onClick
checkOnClickListener(view, attrs);
}
return view;
}
- 解析 xml ，判斷 view 類型，執行個體化指定控件對象
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