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 android.support.v7.widget;
18 
19 import android.annotation.TargetApi;
20 import android.content.Context;
21 import android.os.Build;
22 import android.support.annotation.AttrRes;
23 import android.support.annotation.NonNull;
24 import android.support.annotation.Nullable;
25 import android.support.annotation.StyleRes;
26 import android.support.v4.widget.PopupWindowCompat;
27 import android.support.v7.appcompat.R;
28 import android.util.AttributeSet;
29 import android.util.Log;
30 import android.view.View;
31 import android.view.ViewTreeObserver.OnScrollChangedListener;
32 import android.widget.PopupWindow;
33 
34 import java.lang.ref.WeakReference;
35 import java.lang.reflect.Field;
36 
37 class AppCompatPopupWindow extends PopupWindow {
38 
39     private static final String TAG = "AppCompatPopupWindow";
40     private static final boolean COMPAT_OVERLAP_ANCHOR = Build.VERSION.SDK_INT < 21;
41 
42     private boolean mOverlapAnchor;
43 
44     public AppCompatPopupWindow(@NonNull Context context, @Nullable AttributeSet attrs,
45             @AttrRes int defStyleAttr) {
46         super(context, attrs, defStyleAttr);
47         init(context, attrs, defStyleAttr, 0);
48     }
49 
50     @TargetApi(11)
51     public AppCompatPopupWindow(@NonNull Context context, @Nullable AttributeSet attrs,
52             @AttrRes int defStyleAttr, @StyleRes int defStyleRes) {
53         super(context, attrs, defStyleAttr, defStyleRes);
54         init(context, attrs, defStyleAttr, defStyleRes);
55     }
56 
57     private void init(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
58         TintTypedArray a = TintTypedArray.obtainStyledAttributes(context, attrs,
59                 R.styleable.PopupWindow, defStyleAttr, defStyleRes);
60         if (a.hasValue(R.styleable.PopupWindow_overlapAnchor)) {
61             setSupportOverlapAnchor(a.getBoolean(R.styleable.PopupWindow_overlapAnchor, false));
62         }
63         // We re-set this for tinting purposes
64         setBackgroundDrawable(a.getDrawable(R.styleable.PopupWindow_android_popupBackground));
65 
66         final int sdk = Build.VERSION.SDK_INT;
67         if (defStyleRes != 0 && sdk < 11) {
68             // If we have a defStyleRes, but we're on < API 11, we need to manually set attributes
69             // from the style
70             if (sdk >= 9) {
71                 // android:popupAnimationStyle was added in API 9
72                 if (a.hasValue(R.styleable.PopupWindow_android_popupAnimationStyle)) {
73                     setAnimationStyle(a.getResourceId(
74                             R.styleable.PopupWindow_android_popupAnimationStyle, -1));
75                 }
76             }
77         }
78 
79         a.recycle();
80 
81         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
82             // For devices pre-ICS, we need to wrap the internal OnScrollChangedListener
83             // due to NPEs.
84             wrapOnScrollChangedListener(this);
85         }
86     }
87 
88     @Override
89     public void showAsDropDown(View anchor, int xoff, int yoff) {
90         if (COMPAT_OVERLAP_ANCHOR && mOverlapAnchor) {
91             // If we're pre-L, emulate overlapAnchor by modifying the yOff
92             yoff -= anchor.getHeight();
93         }
94         super.showAsDropDown(anchor, xoff, yoff);
95     }
96 
97     @TargetApi(Build.VERSION_CODES.KITKAT)
98     @Override
99     public void showAsDropDown(View anchor, int xoff, int yoff, int gravity) {
100         if (COMPAT_OVERLAP_ANCHOR && mOverlapAnchor) {
101             // If we're pre-L, emulate overlapAnchor by modifying the yOff
102             yoff -= anchor.getHeight();
103         }
104         super.showAsDropDown(anchor, xoff, yoff, gravity);
105     }
106 
107     @Override
108     public void update(View anchor, int xoff, int yoff, int width, int height) {
109         if (COMPAT_OVERLAP_ANCHOR && mOverlapAnchor) {
110             // If we're pre-L, emulate overlapAnchor by modifying the yOff
111             yoff -= anchor.getHeight();
112         }
113         super.update(anchor, xoff, yoff, width, height);
114     }
115 
116     private static void wrapOnScrollChangedListener(final PopupWindow popup) {
117         try {
118             final Field fieldAnchor = PopupWindow.class.getDeclaredField("mAnchor");
119             fieldAnchor.setAccessible(true);
120 
121             final Field fieldListener = PopupWindow.class
122                     .getDeclaredField("mOnScrollChangedListener");
123             fieldListener.setAccessible(true);
124 
125             final OnScrollChangedListener originalListener =
126                     (OnScrollChangedListener) fieldListener.get(popup);
127 
128             // Now set a new listener, wrapping the original and only proxying the call when
129             // we have an anchor view.
130             fieldListener.set(popup, new OnScrollChangedListener() {
131                 @Override
132                 public void onScrollChanged() {
133                     try {
134                         WeakReference<View> mAnchor = (WeakReference<View>) fieldAnchor.get(popup);
135                         if (mAnchor == null || mAnchor.get() == null) {
136                             return;
137                         } else {
138                             originalListener.onScrollChanged();
139                         }
140                     } catch (IllegalAccessException e) {
141                         // Oh well...
142                     }
143                 }
144             });
145         } catch (Exception e) {
146             Log.d(TAG, "Exception while installing workaround OnScrollChangedListener", e);
147         }
148     }
149 
150     /**
151      * @hide
152      */
153     public void setSupportOverlapAnchor(boolean overlapAnchor) {
154         if (COMPAT_OVERLAP_ANCHOR) {
155             mOverlapAnchor = overlapAnchor;
156         } else {
157             PopupWindowCompat.setOverlapAnchor(this, overlapAnchor);
158         }
159     }
160 
161     /**
162      * @hide
163      */
164     public boolean getSupportOverlapAnchor() {
165         if (COMPAT_OVERLAP_ANCHOR) {
166             return mOverlapAnchor;
167         } else {
168             return PopupWindowCompat.getOverlapAnchor(this);
169         }
170     }
171 
172 }
173