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 android.graphics.drawable;
18 
19 import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
20 
21 import android.graphics.Path;
22 import android.graphics.drawable.GradientDrawable.GradientState;
23 
24 import java.lang.reflect.Field;
25 
26 /**
27  * Delegate implementing the native methods of {@link GradientDrawable}
28  *
29  * Through the layoutlib_create tool, the original native methods of GradientDrawable have been
30  * replaced by calls to methods of the same name in this delegate class.
31  */
32 public class GradientDrawable_Delegate {
33 
34     /**
35      * The ring can be built either by drawing full circles, or by drawing arcs in case the
36      * circle isn't complete. LayoutLib cannot handle drawing full circles (requires path
37      * subtraction). So, if we need to draw full circles, we switch to drawing 99% circle.
38      */
39     @LayoutlibDelegate
buildRing(GradientDrawable thisDrawable, GradientState st)40     /*package*/ static Path buildRing(GradientDrawable thisDrawable, GradientState st) {
41         boolean useLevel = st.mUseLevelForShape;
42         int level = thisDrawable.getLevel();
43         // 10000 is the max level. See android.graphics.drawable.Drawable#getLevel()
44         float sweep = useLevel ? (360.0f * level / 10000.0f) : 360f;
45         Field mLevel = null;
46         if (sweep >= 360 || sweep <= -360) {
47             st.mUseLevelForShape = true;
48             // Use reflection to set the value of the field to prevent setting the drawable to
49             // dirty again.
50             try {
51                 mLevel = Drawable.class.getDeclaredField("mLevel");
52                 mLevel.setAccessible(true);
53                 mLevel.setInt(thisDrawable, 9999);  // set to one less than max.
54             } catch (NoSuchFieldException e) {
55                 // The field has been removed in a recent framework change. Fall back to old
56                 // buggy behaviour.
57             } catch (IllegalAccessException e) {
58                 // We've already set the field to be accessible.
59                 assert false;
60             }
61         }
62         Path path = thisDrawable.buildRing_Original(st);
63         st.mUseLevelForShape = useLevel;
64         if (mLevel != null) {
65             try {
66                 mLevel.setInt(thisDrawable, level);
67             } catch (IllegalAccessException e) {
68                 assert false;
69             }
70         }
71         return path;
72     }
73 }
74