全局修改一些view的属性的简单办法，就是标题的方法
需要在super.onCreate(savedInstanceState)之前添加，因为一个activity只能设置一个，而系统在super方法里也调用了这个方法。。所以我们需要在系统设置之前。
override fun onCreate(savedInstanceState: Bundle?) {
LayoutInflaterCompat.setFactory2(layoutInflater,object :LayoutInflater.Factory2{
override fun onCreateView(parent: View?, name: String?, context: Context, attrs: AttributeSet): View? {
var view=delegate.createView(parent,name,context,attrs);//调用系统的方法
println("onCreateView56=====$name===========${view}")
LinearLayout(context,attrs)
return view
}
override fun onCreateView(name: String?, context: Context?, attrs: AttributeSet?): View? {
return null
}
})
super.onCreate(savedInstanceState)
}
获取id的办法,打印下获取到的id就是 @+十进制id，比如这样id===============@2131296538
(0 until attrs.attributeCount).forEach {
println("${name}=====$it==========${attrs.getAttributeName(it)}")
if(TextUtils.equals("id",attrs.getAttributeName(it))){
try {view.id
println("id===============${attrs.getAttributeValue(it)}")
if(TextUtils.equals(attrs.getAttributeValue(it),"@${android.R.id.message}")){
if(view!=null&& view is TextView){
view.setTextColor(Color.RED)
}
}
}catch (e:Exception){
e.printStackTrace()
}
}
}
然后先说下上边获取的view方法，最终是在这里AppCompatViewInflater类里
可以看到除了基本控件基本返回的view都是null
public 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 = new AppCompatTextView(context, attrs);
break;
case "ImageView":
view = new AppCompatImageView(context, attrs);
break;
case "Button":
view = new AppCompatButton(context, attrs);
break;
case "EditText":
view = new AppCompatEditText(context, attrs);
break;
case "Spinner":
view = new AppCompatSpinner(context, attrs);
break;
case "ImageButton":
view = new AppCompatImageButton(context, attrs);
break;
case "CheckBox":
view = new AppCompatCheckBox(context, attrs);
break;
case "RadioButton":
view = new AppCompatRadioButton(context, attrs);
break;
case "CheckedTextView":
view = new AppCompatCheckedTextView(context, attrs);
break;
case "AutoCompleteTextView":
view = new AppCompatAutoCompleteTextView(context, attrs);
break;
case "MultiAutoCompleteTextView":
view = new AppCompatMultiAutoCompleteTextView(context, attrs);
break;
case "RatingBar":
view = new AppCompatRatingBar(context, attrs);
break;
case "SeekBar":
view = new AppCompatSeekBar(context, attrs);
break;
}
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;
}
我们看下系统的用法，在AppCompatActivity类里
protected void onCreate(@Nullable Bundle savedInstanceState) {
final AppCompatDelegate delegate = getDelegate();
delegate.installViewFactory();
delegate.onCreate(savedInstanceState);
//
@NonNull
public AppCompatDelegate getDelegate() {
if (mDelegate == null) {
mDelegate = AppCompatDelegate.create(this, this);
}
return mDelegate;
}
// public abstract class AppCompatDelegate
public static AppCompatDelegate create(Activity activity, AppCompatCallback callback) {
return create(activity, activity.getWindow(), callback);
}
//
private static AppCompatDelegate create(Context context, Window window,
AppCompatCallback callback) {
if (Build.VERSION.SDK_INT >= 24) {
return new AppCompatDelegateImplN(context, window, callback);
} else if (Build.VERSION.SDK_INT >= 23) {
return new AppCompatDelegateImplV23(context, window, callback);
} else if (Build.VERSION.SDK_INT >= 14) {
return new AppCompatDelegateImplV14(context, window, callback);
} else if (Build.VERSION.SDK_INT >= 11) {
return new AppCompatDelegateImplV11(context, window, callback);
} else {
return new AppCompatDelegateImplV9(context, window, callback);
}
}
在AppCompatDelegateImplV9里实现了最开始的installViewFactory（）
另外在14里边实现了白天黑夜模式
class AppCompatDelegateImplV9 extends AppCompatDelegateImplBase
implements MenuBuilder.Callback, LayoutInflater.Factory2
//可以看到只能设置一个factory
public void installViewFactory() {
LayoutInflater layoutInflater = LayoutInflater.from(mContext);
if (layoutInflater.getFactory() == null) {
LayoutInflaterCompat.setFactory2(layoutInflater, this);
} else {
if (!(layoutInflater.getFactory2() instanceof AppCompatDelegateImplV9)) {
Log.i(TAG, "The Activity's LayoutInflater already has a Factory installed"
+ " so we can not install AppCompat's");
}
}
}
继续往下LayoutInflaterCompat
@RequiresApi(21)
static class LayoutInflaterCompatApi21Impl extends LayoutInflaterCompatBaseImpl {
@SuppressWarnings("deprecation")
@Override
public void setFactory(LayoutInflater inflater, LayoutInflaterFactory factory) {
inflater.setFactory2(factory != null ? new Factory2Wrapper(factory) : null);
}
@Override
public void setFactory2(LayoutInflater inflater, LayoutInflater.Factory2 factory) {
inflater.setFactory2(factory);
}
}
static final LayoutInflaterCompatBaseImpl IMPL;
static {
if (Build.VERSION.SDK_INT >= 21) {
IMPL = new LayoutInflaterCompatApi21Impl();
} else {
IMPL = new LayoutInflaterCompatBaseImpl();
}
}
public static void setFactory2(
@NonNull LayoutInflater inflater, @NonNull LayoutInflater.Factory2 factory) {
IMPL.setFactory2(inflater, factory);
}
//看下impl
static class LayoutInflaterCompatBaseImpl {
@SuppressWarnings("deprecation")
public void setFactory(LayoutInflater inflater, LayoutInflaterFactory factory) {
final LayoutInflater.Factory2 factory2 = factory != null
? new Factory2Wrapper(factory) : null;
setFactory2(inflater, factory2);
}
public void setFactory2(LayoutInflater inflater, LayoutInflater.Factory2 factory) {
inflater.setFactory2(factory);
final LayoutInflater.Factory f = inflater.getFactory();
if (f instanceof LayoutInflater.Factory2) {
// The merged factory is now set to getFactory(), but not getFactory2() (pre-v21).
// We will now try and force set the merged factory to mFactory2
forceSetFactory2(inflater, (LayoutInflater.Factory2) f);//通过反射把factory赋值给LayoutInflater。
} else {
// Else, we will force set the original wrapped Factory2
forceSetFactory2(inflater, factory);
}
}
@SuppressWarnings("deprecation")
public LayoutInflaterFactory getFactory(LayoutInflater inflater) {
LayoutInflater.Factory factory = inflater.getFactory();
if (factory instanceof Factory2Wrapper) {
return ((Factory2Wrapper) factory).mDelegateFactory;
}
return null;
}
}
我们知道我们的布局文件加载就是靠LayoutInflater的，现在看下它的加载
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) + ")");
}
final XmlResourceParser parser = res.getLayout(resource);
try {
return inflate(parser, root, attachToRoot);
} finally {
parser.close();
}
}
//继续看下inflate方法，删掉一些代码，看下核心代码就行
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;
View result = root;
try {
// 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!");
}
final String name = parser.getName();
//处理merge标签的
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");
}
//处理子控件的
rInflate(parser, root, inflaterContext, attrs, false);
} else {
// Temp is the root view that was found in the xml 处理普通布局的
final View temp = createViewFromTag(root, name, inflaterContext, attrs);
ViewGroup.LayoutParams params = null;
if (root != null) {
// Create layout params that match root, if supplied
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);
}
}
// Inflate all children under temp against its context.
rInflateChildren(parser, temp, attrs, true);
// 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) {
} catch (Exception e) {
} finally {
}
return result;
}
}
下边分别说明下上边几个方法
对于merge布局走了这里，就是循环读取标签解析出对应的控件。
/**
* Recursive method used to descend down the xml hierarchy and instantiate
* views, instantiate their children, and then call onFinishInflate().
* <p>
* <strong>Note:</strong> Default visibility so the BridgeInflater can
* override it.
*/
void rInflate(XmlPullParser parser, View parent, Context context,
AttributeSet attrs, boolean finishInflate) throws XmlPullParserException, IOException {
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;
}
final String name = parser.getName();
if (TAG_REQUEST_FOCUS.equals(name)) {
pendingRequestFocus = true;
consumeChildElements(parser);
} else if (TAG_TAG.equals(name)) {
parseViewTag(parser, parent, attrs);
} else if (TAG_INCLUDE.equals(name)) {
if (parser.getDepth() == 0) {
throw new InflateException("<include /> cannot be the root element");
}
parseInclude(parser, context, parent, attrs);
} else if (TAG_MERGE.equals(name)) {
throw new InflateException("<merge /> must be the root element");
} else {
final View view = createViewFromTag(parent, name, context, attrs); //view的最后获取都是在这里的
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
结论是先调用我们设置的factory的方法获取view，如果为空再调用系统原生的。
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();
}
if (name.equals(TAG_1995)) {
// Let's party like it's 1995!
return new BlinkLayout(context, attrs);
}
try {
View view;//可以看到先调用我们设置的factory的方法获取view
if (mFactory2 != null) {
view = mFactory2.onCreateView(parent, name, context, attrs);
} else if (mFactory != null) {
view = mFactory.onCreateView(name, context, attrs);
} else {
view = null;
}
//mPrivateFactory 也是个factory
if (view == null && mPrivateFactory != null) {
view = mPrivateFactory.onCreateView(parent, name, context, attrs);
}
if (view == null) {//如果我们factory的回调方法里返回的view是空的，那么这里处理
final Object lastContext = mConstructorArgs[0];
mConstructorArgs[0] = context;
try {
if (-1 == name.indexOf('.')) {//这里2个就是系统创建view的过程了，不研究
view = onCreateView(parent, name, attrs);
} else {
view = createView(name, null, attrs);
}
} finally {
mConstructorArgs[0] = lastContext;
}
}
return view;
} catch (InflateException e) {
} catch (ClassNotFoundException e) {
} catch (Exception e) {
}
}
在AppCompatDelegateImplV9 createView方法
可以看到调用了AppCompatViewInflater里的createView方法也就是对原始的控件，都改成了AppcompatXXXX的东西。
public View createView(View parent, final String name, @NonNull Context context,
@NonNull AttributeSet attrs) {
if (mAppCompatViewInflater == null) {
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);
}
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 */
);
}
最后稍微总结下：
AppCompatDelegate从v9开始就实现了Factory2，也就是它也是个factory。然后它通过反射赋值给了Layouinflator。 Layouinflator加载布局的过程我们也分析了，里边就有用到factory，先通过factory获取view【就是在这里完成了对原始view的修改】，获取 为空的话再用最原始的方法生成view。
看下v9下， mFactory2.onCreateView() 其实最终还是掉的createView方法，这个方法又跑到AppCompatViewInflater里的createView方法里的，这是最终修改view的地方。
public final View onCreateView(View parent, String name, Context context, AttributeSet attrs) {
// First let the Activity's Factory try and inflate the view
final View view = callActivityOnCreateView(parent, name, context, attrs);
if (view != null) {
return view;
}
// If the Factory didn't handle it, let our createView() method try
return createView(parent, name, context, attrs);
}
