1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package androidx.appcompat.app;
18 
19 import android.content.Context;
20 import android.content.ContextWrapper;
21 import android.content.res.TypedArray;
22 import android.os.Build;
23 import android.util.AttributeSet;
24 import android.util.Log;
25 import android.view.InflateException;
26 import android.view.View;
27 
28 import androidx.annotation.NonNull;
29 import androidx.annotation.Nullable;
30 import androidx.appcompat.R;
31 import androidx.appcompat.view.ContextThemeWrapper;
32 import androidx.appcompat.widget.AppCompatAutoCompleteTextView;
33 import androidx.appcompat.widget.AppCompatButton;
34 import androidx.appcompat.widget.AppCompatCheckBox;
35 import androidx.appcompat.widget.AppCompatCheckedTextView;
36 import androidx.appcompat.widget.AppCompatEditText;
37 import androidx.appcompat.widget.AppCompatImageButton;
38 import androidx.appcompat.widget.AppCompatImageView;
39 import androidx.appcompat.widget.AppCompatMultiAutoCompleteTextView;
40 import androidx.appcompat.widget.AppCompatRadioButton;
41 import androidx.appcompat.widget.AppCompatRatingBar;
42 import androidx.appcompat.widget.AppCompatSeekBar;
43 import androidx.appcompat.widget.AppCompatSpinner;
44 import androidx.appcompat.widget.AppCompatTextView;
45 import androidx.appcompat.widget.TintContextWrapper;
46 import androidx.collection.ArrayMap;
47 import androidx.core.view.ViewCompat;
48 
49 import java.lang.reflect.Constructor;
50 import java.lang.reflect.InvocationTargetException;
51 import java.lang.reflect.Method;
52 import java.util.Map;
53 
54 /**
55  * This class is responsible for manually inflating our tinted widgets.
56  * <p>This class two main responsibilities: the first is to 'inject' our tinted views in place of
57  * the framework versions in layout inflation; the second is backport the {@code android:theme}
58  * functionality for any inflated widgets. This include theme inheritance from its parent.
59  */
60 public class AppCompatViewInflater {
61 
62     private static final Class<?>[] sConstructorSignature = new Class[]{
63             Context.class, AttributeSet.class};
64     private static final int[] sOnClickAttrs = new int[]{android.R.attr.onClick};
65 
66     private static final String[] sClassPrefixList = {
67             "android.widget.",
68             "android.view.",
69             "android.webkit."
70     };
71 
72     private static final String LOG_TAG = "AppCompatViewInflater";
73 
74     private static final Map<String, Constructor<? extends View>> sConstructorMap
75             = new ArrayMap<>();
76 
77     private final Object[] mConstructorArgs = new Object[2];
78 
createView(View parent, final String name, @NonNull Context context, @NonNull AttributeSet attrs, boolean inheritContext, boolean readAndroidTheme, boolean readAppTheme, boolean wrapContext)79     final View createView(View parent, final String name, @NonNull Context context,
80             @NonNull AttributeSet attrs, boolean inheritContext,
81             boolean readAndroidTheme, boolean readAppTheme, boolean wrapContext) {
82         final Context originalContext = context;
83 
84         // We can emulate Lollipop's android:theme attribute propagating down the view hierarchy
85         // by using the parent's context
86         if (inheritContext && parent != null) {
87             context = parent.getContext();
88         }
89         if (readAndroidTheme || readAppTheme) {
90             // We then apply the theme on the context, if specified
91             context = themifyContext(context, attrs, readAndroidTheme, readAppTheme);
92         }
93         if (wrapContext) {
94             context = TintContextWrapper.wrap(context);
95         }
96 
97         View view = null;
98 
99         // We need to 'inject' our tint aware Views in place of the standard framework versions
100         switch (name) {
101             case "TextView":
102                 view = createTextView(context, attrs);
103                 verifyNotNull(view, name);
104                 break;
105             case "ImageView":
106                 view = createImageView(context, attrs);
107                 verifyNotNull(view, name);
108                 break;
109             case "Button":
110                 view = createButton(context, attrs);
111                 verifyNotNull(view, name);
112                 break;
113             case "EditText":
114                 view = createEditText(context, attrs);
115                 verifyNotNull(view, name);
116                 break;
117             case "Spinner":
118                 view = createSpinner(context, attrs);
119                 verifyNotNull(view, name);
120                 break;
121             case "ImageButton":
122                 view = createImageButton(context, attrs);
123                 verifyNotNull(view, name);
124                 break;
125             case "CheckBox":
126                 view = createCheckBox(context, attrs);
127                 verifyNotNull(view, name);
128                 break;
129             case "RadioButton":
130                 view = createRadioButton(context, attrs);
131                 verifyNotNull(view, name);
132                 break;
133             case "CheckedTextView":
134                 view = createCheckedTextView(context, attrs);
135                 verifyNotNull(view, name);
136                 break;
137             case "AutoCompleteTextView":
138                 view = createAutoCompleteTextView(context, attrs);
139                 verifyNotNull(view, name);
140                 break;
141             case "MultiAutoCompleteTextView":
142                 view = createMultiAutoCompleteTextView(context, attrs);
143                 verifyNotNull(view, name);
144                 break;
145             case "RatingBar":
146                 view = createRatingBar(context, attrs);
147                 verifyNotNull(view, name);
148                 break;
149             case "SeekBar":
150                 view = createSeekBar(context, attrs);
151                 verifyNotNull(view, name);
152                 break;
153             default:
154                 // The fallback that allows extending class to take over view inflation
155                 // for other tags. Note that we don't check that the result is not-null.
156                 // That allows the custom inflater path to fall back on the default one
157                 // later in this method.
158                 view = createView(context, name, attrs);
159         }
160 
161         if (view == null && originalContext != context) {
162             // If the original context does not equal our themed context, then we need to manually
163             // inflate it using the name so that android:theme takes effect.
164             view = createViewFromTag(context, name, attrs);
165         }
166 
167         if (view != null) {
168             // If we have created a view, check its android:onClick
169             checkOnClickListener(view, attrs);
170         }
171 
172         return view;
173     }
174 
175     @NonNull
createTextView(Context context, AttributeSet attrs)176     protected AppCompatTextView createTextView(Context context, AttributeSet attrs) {
177         return new AppCompatTextView(context, attrs);
178     }
179 
180     @NonNull
createImageView(Context context, AttributeSet attrs)181     protected AppCompatImageView createImageView(Context context, AttributeSet attrs) {
182         return new AppCompatImageView(context, attrs);
183     }
184 
185     @NonNull
createButton(Context context, AttributeSet attrs)186     protected AppCompatButton createButton(Context context, AttributeSet attrs) {
187         return new AppCompatButton(context, attrs);
188     }
189 
190     @NonNull
createEditText(Context context, AttributeSet attrs)191     protected AppCompatEditText createEditText(Context context, AttributeSet attrs) {
192         return new AppCompatEditText(context, attrs);
193     }
194 
195     @NonNull
createSpinner(Context context, AttributeSet attrs)196     protected AppCompatSpinner createSpinner(Context context, AttributeSet attrs) {
197         return new AppCompatSpinner(context, attrs);
198     }
199 
200     @NonNull
createImageButton(Context context, AttributeSet attrs)201     protected AppCompatImageButton createImageButton(Context context, AttributeSet attrs) {
202         return new AppCompatImageButton(context, attrs);
203     }
204 
205     @NonNull
createCheckBox(Context context, AttributeSet attrs)206     protected AppCompatCheckBox createCheckBox(Context context, AttributeSet attrs) {
207         return new AppCompatCheckBox(context, attrs);
208     }
209 
210     @NonNull
createRadioButton(Context context, AttributeSet attrs)211     protected AppCompatRadioButton createRadioButton(Context context, AttributeSet attrs) {
212         return new AppCompatRadioButton(context, attrs);
213     }
214 
215     @NonNull
createCheckedTextView(Context context, AttributeSet attrs)216     protected AppCompatCheckedTextView createCheckedTextView(Context context, AttributeSet attrs) {
217         return new AppCompatCheckedTextView(context, attrs);
218     }
219 
220     @NonNull
createAutoCompleteTextView(Context context, AttributeSet attrs)221     protected AppCompatAutoCompleteTextView createAutoCompleteTextView(Context context,
222             AttributeSet attrs) {
223         return new AppCompatAutoCompleteTextView(context, attrs);
224     }
225 
226     @NonNull
createMultiAutoCompleteTextView(Context context, AttributeSet attrs)227     protected AppCompatMultiAutoCompleteTextView createMultiAutoCompleteTextView(Context context,
228             AttributeSet attrs) {
229         return new AppCompatMultiAutoCompleteTextView(context, attrs);
230     }
231 
232     @NonNull
createRatingBar(Context context, AttributeSet attrs)233     protected AppCompatRatingBar createRatingBar(Context context, AttributeSet attrs) {
234         return new AppCompatRatingBar(context, attrs);
235     }
236 
237     @NonNull
createSeekBar(Context context, AttributeSet attrs)238     protected AppCompatSeekBar createSeekBar(Context context, AttributeSet attrs) {
239         return new AppCompatSeekBar(context, attrs);
240     }
241 
verifyNotNull(View view, String name)242     private void verifyNotNull(View view, String name) {
243         if (view == null) {
244             throw new IllegalStateException(this.getClass().getName()
245                     + " asked to inflate view for <" + name + ">, but returned null");
246         }
247     }
248 
249     @Nullable
createView(Context context, String name, AttributeSet attrs)250     protected View createView(Context context, String name, AttributeSet attrs) {
251         return null;
252     }
253 
createViewFromTag(Context context, String name, AttributeSet attrs)254     private View createViewFromTag(Context context, String name, AttributeSet attrs) {
255         if (name.equals("view")) {
256             name = attrs.getAttributeValue(null, "class");
257         }
258 
259         try {
260             mConstructorArgs[0] = context;
261             mConstructorArgs[1] = attrs;
262 
263             if (-1 == name.indexOf('.')) {
264                 for (int i = 0; i < sClassPrefixList.length; i++) {
265                     final View view = createViewByPrefix(context, name, sClassPrefixList[i]);
266                     if (view != null) {
267                         return view;
268                     }
269                 }
270                 return null;
271             } else {
272                 return createViewByPrefix(context, name, null);
273             }
274         } catch (Exception e) {
275             // We do not want to catch these, lets return null and let the actual LayoutInflater
276             // try
277             return null;
278         } finally {
279             // Don't retain references on context.
280             mConstructorArgs[0] = null;
281             mConstructorArgs[1] = null;
282         }
283     }
284 
285     /**
286      * android:onClick doesn't handle views with a ContextWrapper context. This method
287      * backports new framework functionality to traverse the Context wrappers to find a
288      * suitable target.
289      */
checkOnClickListener(View view, AttributeSet attrs)290     private void checkOnClickListener(View view, AttributeSet attrs) {
291         final Context context = view.getContext();
292 
293         if (!(context instanceof ContextWrapper) ||
294                 (Build.VERSION.SDK_INT >= 15 && !ViewCompat.hasOnClickListeners(view))) {
295             // Skip our compat functionality if: the Context isn't a ContextWrapper, or
296             // the view doesn't have an OnClickListener (we can only rely on this on API 15+ so
297             // always use our compat code on older devices)
298             return;
299         }
300 
301         final TypedArray a = context.obtainStyledAttributes(attrs, sOnClickAttrs);
302         final String handlerName = a.getString(0);
303         if (handlerName != null) {
304             view.setOnClickListener(new DeclaredOnClickListener(view, handlerName));
305         }
306         a.recycle();
307     }
308 
createViewByPrefix(Context context, String name, String prefix)309     private View createViewByPrefix(Context context, String name, String prefix)
310             throws ClassNotFoundException, InflateException {
311         Constructor<? extends View> constructor = sConstructorMap.get(name);
312 
313         try {
314             if (constructor == null) {
315                 // Class not found in the cache, see if it's real, and try to add it
316                 Class<? extends View> clazz = context.getClassLoader().loadClass(
317                         prefix != null ? (prefix + name) : name).asSubclass(View.class);
318 
319                 constructor = clazz.getConstructor(sConstructorSignature);
320                 sConstructorMap.put(name, constructor);
321             }
322             constructor.setAccessible(true);
323             return constructor.newInstance(mConstructorArgs);
324         } catch (Exception e) {
325             // We do not want to catch these, lets return null and let the actual LayoutInflater
326             // try
327             return null;
328         }
329     }
330 
331     /**
332      * Allows us to emulate the {@code android:theme} attribute for devices before L.
333      */
themifyContext(Context context, AttributeSet attrs, boolean useAndroidTheme, boolean useAppTheme)334     private static Context themifyContext(Context context, AttributeSet attrs,
335             boolean useAndroidTheme, boolean useAppTheme) {
336         final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.View, 0, 0);
337         int themeId = 0;
338         if (useAndroidTheme) {
339             // First try reading android:theme if enabled
340             themeId = a.getResourceId(R.styleable.View_android_theme, 0);
341         }
342         if (useAppTheme && themeId == 0) {
343             // ...if that didn't work, try reading app:theme (for legacy reasons) if enabled
344             themeId = a.getResourceId(R.styleable.View_theme, 0);
345 
346             if (themeId != 0) {
347                 Log.i(LOG_TAG, "app:theme is now deprecated. "
348                         + "Please move to using android:theme instead.");
349             }
350         }
351         a.recycle();
352 
353         if (themeId != 0 && (!(context instanceof ContextThemeWrapper)
354                 || ((ContextThemeWrapper) context).getThemeResId() != themeId)) {
355             // If the context isn't a ContextThemeWrapper, or it is but does not have
356             // the same theme as we need, wrap it in a new wrapper
357             context = new ContextThemeWrapper(context, themeId);
358         }
359         return context;
360     }
361 
362     /**
363      * An implementation of OnClickListener that attempts to lazily load a
364      * named click handling method from a parent or ancestor context.
365      */
366     private static class DeclaredOnClickListener implements View.OnClickListener {
367         private final View mHostView;
368         private final String mMethodName;
369 
370         private Method mResolvedMethod;
371         private Context mResolvedContext;
372 
DeclaredOnClickListener(@onNull View hostView, @NonNull String methodName)373         public DeclaredOnClickListener(@NonNull View hostView, @NonNull String methodName) {
374             mHostView = hostView;
375             mMethodName = methodName;
376         }
377 
378         @Override
onClick(@onNull View v)379         public void onClick(@NonNull View v) {
380             if (mResolvedMethod == null) {
381                 resolveMethod(mHostView.getContext(), mMethodName);
382             }
383 
384             try {
385                 mResolvedMethod.invoke(mResolvedContext, v);
386             } catch (IllegalAccessException e) {
387                 throw new IllegalStateException(
388                         "Could not execute non-public method for android:onClick", e);
389             } catch (InvocationTargetException e) {
390                 throw new IllegalStateException(
391                         "Could not execute method for android:onClick", e);
392             }
393         }
394 
395         @NonNull
resolveMethod(@ullable Context context, @NonNull String name)396         private void resolveMethod(@Nullable Context context, @NonNull String name) {
397             while (context != null) {
398                 try {
399                     if (!context.isRestricted()) {
400                         final Method method = context.getClass().getMethod(mMethodName, View.class);
401                         if (method != null) {
402                             mResolvedMethod = method;
403                             mResolvedContext = context;
404                             return;
405                         }
406                     }
407                 } catch (NoSuchMethodException e) {
408                     // Failed to find method, keep searching up the hierarchy.
409                 }
410 
411                 if (context instanceof ContextWrapper) {
412                     context = ((ContextWrapper) context).getBaseContext();
413                 } else {
414                     // Can't search up the hierarchy, null out and fail.
415                     context = null;
416                 }
417             }
418 
419             final int id = mHostView.getId();
420             final String idText = id == View.NO_ID ? "" : " with id '"
421                     + mHostView.getContext().getResources().getResourceEntryName(id) + "'";
422             throw new IllegalStateException("Could not find method " + mMethodName
423                     + "(View) in a parent or ancestor Context for android:onClick "
424                     + "attribute defined on view " + mHostView.getClass() + idText);
425         }
426     }
427 }
428