1 /*
2  * Copyright (C) 2016 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.setupwizardlib.span;
18 
19 import android.content.Context;
20 import android.content.ContextWrapper;
21 import android.graphics.Typeface;
22 import android.os.Build;
23 import androidx.annotation.Nullable;
24 import android.text.Selection;
25 import android.text.Spannable;
26 import android.text.TextPaint;
27 import android.text.style.ClickableSpan;
28 import android.util.Log;
29 import android.view.View;
30 import android.widget.TextView;
31 
32 /**
33  * A clickable span that will listen for click events and send it back to the context. To use this
34  * class, implement {@link OnLinkClickListener} in your TextView, or use {@link
35  * com.android.setupwizardlib.view.RichTextView#setOnClickListener(View.OnClickListener)}.
36  *
37  * <p>Note on accessibility: For TalkBack to be able to traverse and interact with the links, you
38  * should use {@code LinkAccessibilityHelper} in your {@code TextView} subclass. Optionally you can
39  * also use {@code RichTextView}, which includes link support.
40  */
41 public class LinkSpan extends ClickableSpan {
42 
43   /*
44    * Implementation note: When the orientation changes, TextView retains a reference to this span
45    * instead of writing it to a parcel (ClickableSpan is not Parcelable). If this class has any
46    * reference to the containing Activity (i.e. the activity context, or any views in the
47    * activity), it will cause memory leak.
48    */
49 
50   /* static section */
51 
52   private static final String TAG = "LinkSpan";
53 
54   private static final Typeface TYPEFACE_MEDIUM =
55       Typeface.create("sans-serif-medium", Typeface.NORMAL);
56 
57   /** @deprecated Use {@link OnLinkClickListener} */
58   @Deprecated
59   public interface OnClickListener {
onClick(LinkSpan span)60     void onClick(LinkSpan span);
61   }
62 
63   /**
64    * Listener that is invoked when a link span is clicked. If the containing view of this span
65    * implements this interface, this will be invoked when the link is clicked.
66    */
67   public interface OnLinkClickListener {
68 
69     /**
70      * Called when a link has been clicked.
71      *
72      * @param span The span that was clicked.
73      * @return True if the click was handled, stopping further propagation of the click event.
74      */
onLinkClick(LinkSpan span)75     boolean onLinkClick(LinkSpan span);
76   }
77 
78   /* non-static section */
79 
80   private final String id;
81 
LinkSpan(String id)82   public LinkSpan(String id) {
83     this.id = id;
84   }
85 
86   @Override
onClick(View view)87   public void onClick(View view) {
88     if (dispatchClick(view)) {
89       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
90         // Prevent the touch event from bubbling up to the parent views.
91         view.cancelPendingInputEvents();
92       }
93     } else {
94       Log.w(TAG, "Dropping click event. No listener attached.");
95     }
96     if (view instanceof TextView) {
97       // Remove the highlight effect when the click happens by clearing the selection
98       CharSequence text = ((TextView) view).getText();
99       if (text instanceof Spannable) {
100         Selection.setSelection((Spannable) text, 0);
101       }
102     }
103   }
104 
dispatchClick(View view)105   private boolean dispatchClick(View view) {
106     boolean handled = false;
107     if (view instanceof OnLinkClickListener) {
108       handled = ((OnLinkClickListener) view).onLinkClick(this);
109     }
110     if (!handled) {
111       final OnClickListener listener = getLegacyListenerFromContext(view.getContext());
112       if (listener != null) {
113         listener.onClick(this);
114         handled = true;
115       }
116     }
117     return handled;
118   }
119 
120   /** @deprecated Deprecated together with {@link OnClickListener} */
121   @Nullable
122   @Deprecated
getLegacyListenerFromContext(@ullable Context context)123   private OnClickListener getLegacyListenerFromContext(@Nullable Context context) {
124     while (true) {
125       if (context instanceof OnClickListener) {
126         return (OnClickListener) context;
127       } else if (context instanceof ContextWrapper) {
128         // Unwrap any context wrapper, in base the base context implements onClickListener.
129         // ContextWrappers cannot have circular base contexts, so at some point this will
130         // reach the one of the other cases and return.
131         context = ((ContextWrapper) context).getBaseContext();
132       } else {
133         return null;
134       }
135     }
136   }
137 
138   @Override
updateDrawState(TextPaint drawState)139   public void updateDrawState(TextPaint drawState) {
140     super.updateDrawState(drawState);
141     drawState.setUnderlineText(false);
142     drawState.setTypeface(TYPEFACE_MEDIUM);
143   }
144 
getId()145   public String getId() {
146     return id;
147   }
148 }
149