Home | History | Annotate | Download | only in view 
      1 /*
      2  * Copyright (C) 2011 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 android.view;
     18 
     19 import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
     20 
     21 import org.xmlpull.v1.XmlPullParser;
     22 import org.xmlpull.v1.XmlPullParserException;
     23 
     24 import android.content.Context;
     25 import android.content.res.TypedArray;
     26 import android.content.res.XmlResourceParser;
     27 import android.util.AttributeSet;
     28 import android.util.TypedValue;
     29 import android.util.Xml;
     30 
     31 import java.io.IOException;
     32 
     33 /**
     34  * Delegate used to provide new implementation of a select few methods of {@link LayoutInflater}
     35  *
     36  * Through the layoutlib_create tool, the original  methods of LayoutInflater have been replaced
     37  * by calls to methods of the same name in this delegate class.
     38  *
     39  */
     40 public class LayoutInflater_Delegate {
     41     private static final String TAG_MERGE = "merge";
     42 
     43     private static final String ATTR_LAYOUT = "layout";
     44 
     45     private static final int[] ATTRS_THEME = new int[] {
     46             com.android.internal.R.attr.theme };
     47 
     48     public static boolean sIsInInclude = false;
     49 
     50     /**
     51      * Recursive method used to descend down the xml hierarchy and instantiate
     52      * views, instantiate their children, and then call onFinishInflate().
     53      *
     54      * This implementation just records the merge status before calling the default implementation.
     55      */
     56     @LayoutlibDelegate
     57     /* package */ static void rInflate(LayoutInflater thisInflater, XmlPullParser parser,
     58             View parent, Context context, AttributeSet attrs, boolean finishInflate)
     59             throws XmlPullParserException, IOException {
     60 
     61         if (finishInflate == false) {
     62             // this is a merge rInflate!
     63             if (thisInflater instanceof BridgeInflater) {
     64                 ((BridgeInflater) thisInflater).setIsInMerge(true);
     65             }
     66         }
     67 
     68         // ---- START DEFAULT IMPLEMENTATION.
     69 
     70         thisInflater.rInflate_Original(parser, parent, context, attrs, finishInflate);
     71 
     72         // ---- END DEFAULT IMPLEMENTATION.
     73 
     74         if (finishInflate == false) {
     75             // this is a merge rInflate!
     76             if (thisInflater instanceof BridgeInflater) {
     77                 ((BridgeInflater) thisInflater).setIsInMerge(false);
     78             }
     79         }
     80     }
     81 
     82     @LayoutlibDelegate
     83     public static void parseInclude(LayoutInflater thisInflater, XmlPullParser parser,
     84             Context context, View parent, AttributeSet attrs)
     85             throws XmlPullParserException, IOException {
     86         int type;
     87 
     88         if (parent instanceof ViewGroup) {
     89             // Apply a theme wrapper, if requested. This is sort of a weird
     90             // edge case, since developers think the <include> overwrites
     91             // values in the AttributeSet of the included View. So, if the
     92             // included View has a theme attribute, we'll need to ignore it.
     93             final TypedArray ta = context.obtainStyledAttributes(attrs, ATTRS_THEME);
     94             final int themeResId = ta.getResourceId(0, 0);
     95             final boolean hasThemeOverride = themeResId != 0;
     96             if (hasThemeOverride) {
     97                 context = new ContextThemeWrapper(context, themeResId);
     98             }
     99             ta.recycle();
    100 
    101             // If the layout is pointing to a theme attribute, we have to
    102             // massage the value to get a resource identifier out of it.
    103             int layout = attrs.getAttributeResourceValue(null, ATTR_LAYOUT, 0);
    104             if (layout == 0) {
    105                 final String value = attrs.getAttributeValue(null, ATTR_LAYOUT);
    106                 if (value == null || value.length() <= 0) {
    107                     throw new InflateException("You must specify a layout in the"
    108                             + " include tag: <include layout=\"@layout/layoutID\" />");
    109                 }
    110 
    111                 // Attempt to resolve the "?attr/name" string to an identifier.
    112                 layout = context.getResources().getIdentifier(value.substring(1), null, null);
    113             }
    114 
    115             // The layout might be referencing a theme attribute.
    116             // ---- START CHANGES
    117             if (layout != 0) {
    118                 final TypedValue tempValue = new TypedValue();
    119                 if (context.getTheme().resolveAttribute(layout, tempValue, true)) {
    120                     layout = tempValue.resourceId;
    121                 }
    122             }
    123             // ---- END CHANGES
    124 
    125             if (layout == 0) {
    126                 final String value = attrs.getAttributeValue(null, ATTR_LAYOUT);
    127                 if (value == null) {
    128                     throw new InflateException("You must specifiy a layout in the"
    129                             + " include tag: <include layout=\"@layout/layoutID\" />");
    130                 } else {
    131                     throw new InflateException("You must specifiy a valid layout "
    132                             + "reference. The layout ID " + value + " is not valid.");
    133                 }
    134             } else {
    135                 final XmlResourceParser childParser =
    136                     thisInflater.getContext().getResources().getLayout(layout);
    137 
    138                 try {
    139                     final AttributeSet childAttrs = Xml.asAttributeSet(childParser);
    140 
    141                     while ((type = childParser.next()) != XmlPullParser.START_TAG &&
    142                             type != XmlPullParser.END_DOCUMENT) {
    143                         // Empty.
    144                     }
    145 
    146                     if (type != XmlPullParser.START_TAG) {
    147                         throw new InflateException(childParser.getPositionDescription() +
    148                                 ": No start tag found!");
    149                     }
    150 
    151                     final String childName = childParser.getName();
    152 
    153                     if (TAG_MERGE.equals(childName)) {
    154                         // Inflate all children.
    155                         thisInflater.rInflate(childParser, parent, context, childAttrs, false);
    156                     } else {
    157                         final View view = thisInflater.createViewFromTag(parent, childName,
    158                                 context, childAttrs, hasThemeOverride);
    159                         final ViewGroup group = (ViewGroup) parent;
    160 
    161                         final TypedArray a = context.obtainStyledAttributes(
    162                                 attrs, com.android.internal.R.styleable.Include);
    163                         final int id = a.getResourceId(
    164                                 com.android.internal.R.styleable.Include_id, View.NO_ID);
    165                         final int visibility = a.getInt(
    166                                 com.android.internal.R.styleable.Include_visibility, -1);
    167                         a.recycle();
    168 
    169                         // We try to load the layout params set in the <include /> tag. If
    170                         // they don't exist, we will rely on the layout params set in the
    171                         // included XML file.
    172                         // During a layoutparams generation, a runtime exception is thrown
    173                         // if either layout_width or layout_height is missing. We catch
    174                         // this exception and set localParams accordingly: true means we
    175                         // successfully loaded layout params from the <include /> tag,
    176                         // false means we need to rely on the included layout params.
    177                         ViewGroup.LayoutParams params = null;
    178                         try {
    179                             // ---- START CHANGES
    180                             sIsInInclude = true;
    181                             // ---- END CHANGES
    182 
    183                             params = group.generateLayoutParams(attrs);
    184                         } catch (RuntimeException ignored) {
    185                             // Ignore, just fail over to child attrs.
    186                         } finally {
    187                             // ---- START CHANGES
    188                             sIsInInclude = false;
    189                             // ---- END CHANGES
    190                         }
    191                         if (params == null) {
    192                             params = group.generateLayoutParams(childAttrs);
    193                         }
    194                         view.setLayoutParams(params);
    195 
    196                         // Inflate all children.
    197                         thisInflater.rInflateChildren(childParser, view, childAttrs, true);
    198 
    199                         if (id != View.NO_ID) {
    200                             view.setId(id);
    201                         }
    202 
    203                         switch (visibility) {
    204                             case 0:
    205                                 view.setVisibility(View.VISIBLE);
    206                                 break;
    207                             case 1:
    208                                 view.setVisibility(View.INVISIBLE);
    209                                 break;
    210                             case 2:
    211                                 view.setVisibility(View.GONE);
    212                                 break;
    213                         }
    214 
    215                         group.addView(view);
    216                     }
    217                 } finally {
    218                     childParser.close();
    219                 }
    220             }
    221         } else {
    222             throw new InflateException("<include /> can only be used inside of a ViewGroup");
    223         }
    224 
    225         LayoutInflater.consumeChildElements(parser);
    226     }
    227 }
    228