1 /*
2  * Copyright (C) 2015 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 com.android.layoutlib.bridge.android.support;
18 
19 import com.android.ide.common.rendering.api.LayoutLog;
20 import com.android.ide.common.rendering.api.LayoutlibCallback;
21 import com.android.layoutlib.bridge.Bridge;
22 import com.android.layoutlib.bridge.android.BridgeContext;
23 import com.android.layoutlib.bridge.android.RenderParamsFlags;
24 import com.android.layoutlib.bridge.util.ReflectionUtils.ReflectionException;
25 
26 import android.annotation.NonNull;
27 import android.annotation.Nullable;
28 import android.content.Context;
29 import android.view.View;
30 
31 import static com.android.layoutlib.bridge.util.ReflectionUtils.getCause;
32 import static com.android.layoutlib.bridge.util.ReflectionUtils.getMethod;
33 import static com.android.layoutlib.bridge.util.ReflectionUtils.invoke;
34 
35 /**
36  * Utility class for working with android.support.v7.widget.RecyclerView
37  */
38 public class RecyclerViewUtil {
39 
40     private static final String RV_PKG_PREFIX = "android.support.v7.widget.";
41     public static final String CN_RECYCLER_VIEW = RV_PKG_PREFIX + "RecyclerView";
42     private static final String CN_LAYOUT_MANAGER = CN_RECYCLER_VIEW + "$LayoutManager";
43     private static final String CN_ADAPTER = CN_RECYCLER_VIEW + "$Adapter";
44 
45     // LinearLayoutManager related constants.
46     private static final String CN_LINEAR_LAYOUT_MANAGER = RV_PKG_PREFIX + "LinearLayoutManager";
47     private static final Class<?>[] LLM_CONSTRUCTOR_SIGNATURE = new Class<?>[]{Context.class};
48 
49     /**
50      * Tries to create an Adapter ({@code android.support.v7.widget.RecyclerView.Adapter} and a
51      * LayoutManager {@code RecyclerView.LayoutManager} and assign these to the {@code RecyclerView}
52      * that is passed.
53      * <p/>
54      * Any exceptions thrown during the process are logged in {@link Bridge#getLog()}
55      */
setAdapter(@onNull View recyclerView, @NonNull BridgeContext context, @NonNull LayoutlibCallback layoutlibCallback, int adapterLayout)56     public static void setAdapter(@NonNull View recyclerView, @NonNull BridgeContext context,
57             @NonNull LayoutlibCallback layoutlibCallback, int adapterLayout) {
58         try {
59             setLayoutManager(recyclerView, context, layoutlibCallback);
60             Object adapter = createAdapter(layoutlibCallback);
61             if (adapter != null) {
62                 setProperty(recyclerView, CN_ADAPTER, adapter, "setAdapter");
63                 setProperty(adapter, int.class, adapterLayout, "setLayoutId");
64             }
65         } catch (ReflectionException e) {
66             Throwable cause = getCause(e);
67             Bridge.getLog().error(LayoutLog.TAG_BROKEN,
68                     "Error occurred while trying to setup RecyclerView.", cause, null);
69         }
70     }
71 
setLayoutManager(@onNull View recyclerView, @NonNull BridgeContext context, @NonNull LayoutlibCallback callback)72     private static void setLayoutManager(@NonNull View recyclerView, @NonNull BridgeContext context,
73             @NonNull LayoutlibCallback callback) throws ReflectionException {
74         if (getLayoutManager(recyclerView) == null) {
75             // Only set the layout manager if not already set by the recycler view.
76             Object layoutManager = createLayoutManager(context, callback);
77             if (layoutManager != null) {
78                 setProperty(recyclerView, CN_LAYOUT_MANAGER, layoutManager, "setLayoutManager");
79             }
80         }
81     }
82 
83     /** Creates a LinearLayoutManager using the provided context. */
84     @Nullable
createLayoutManager(@onNull Context context, @NonNull LayoutlibCallback callback)85     private static Object createLayoutManager(@NonNull Context context,
86             @NonNull LayoutlibCallback callback)
87             throws ReflectionException {
88         try {
89             return callback.loadView(CN_LINEAR_LAYOUT_MANAGER, LLM_CONSTRUCTOR_SIGNATURE,
90                     new Object[]{context});
91         } catch (Exception e) {
92             throw new ReflectionException(e);
93         }
94     }
95 
96     @Nullable
getLayoutManager(View recyclerView)97     private static Object getLayoutManager(View recyclerView) throws ReflectionException {
98         return invoke(getMethod(recyclerView.getClass(), "getLayoutManager"), recyclerView);
99     }
100 
101     @Nullable
createAdapter(@onNull LayoutlibCallback layoutlibCallback)102     private static Object createAdapter(@NonNull LayoutlibCallback layoutlibCallback)
103             throws ReflectionException {
104         Boolean ideSupport =
105                 layoutlibCallback.getFlag(RenderParamsFlags.FLAG_KEY_RECYCLER_VIEW_SUPPORT);
106         if (ideSupport != Boolean.TRUE) {
107             return null;
108         }
109         try {
110             return layoutlibCallback.loadClass(CN_ADAPTER, new Class[0], new Object[0]);
111         } catch (Exception e) {
112             throw new ReflectionException(e);
113         }
114     }
115 
setProperty(@onNull Object object, @NonNull String propertyClassName, @NonNull Object propertyValue, @NonNull String propertySetter)116     private static void setProperty(@NonNull Object object, @NonNull String propertyClassName,
117       @NonNull Object propertyValue, @NonNull String propertySetter)
118             throws ReflectionException {
119         Class<?> propertyClass = getClassInstance(propertyValue, propertyClassName);
120         setProperty(object, propertyClass, propertyValue, propertySetter);
121     }
122 
setProperty(@onNull Object object, @NonNull Class<?> propertyClass, @Nullable Object propertyValue, @NonNull String propertySetter)123     private static void setProperty(@NonNull Object object, @NonNull Class<?> propertyClass,
124             @Nullable Object propertyValue, @NonNull String propertySetter)
125             throws ReflectionException {
126         invoke(getMethod(object.getClass(), propertySetter, propertyClass), object, propertyValue);
127     }
128 
129     /**
130      * Looks through the class hierarchy of {@code object} at runtime and returns the class matching
131      * the name {@code className}.
132      * <p/>
133      * This is used when we cannot use Class.forName() since the class we want was loaded from a
134      * different ClassLoader.
135      */
136     @NonNull
getClassInstance(@onNull Object object, @NonNull String className)137     private static Class<?> getClassInstance(@NonNull Object object, @NonNull String className) {
138         Class<?> superClass = object.getClass();
139         while (superClass != null) {
140             if (className.equals(superClass.getName())) {
141                 return superClass;
142             }
143             superClass = superClass.getSuperclass();
144         }
145         throw new RuntimeException("invalid object/classname combination.");
146     }
147 }
148