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