基於Android開發支持表情的實現詳解

最近項目需要支持表情，表情的添加和解析實現基本上是參照Android自身的SmileyParser，具體就不多講了，直接貼上代碼：
代碼如下：

public class SmileyParser {
private static SmileyParser sInstance = null;

private Context mContext = null;
private Pattern mPattern = null;
private HashMap<String, Integer> mSmileyTextToId = null;
private final String[] mSmileyArrays =
{"/西瓜","89","/便便","59","/太陽","74","/偷笑","20","/傲慢","23","/再見","39","/凋謝","64","/發呆","3","/發怒","11","/閃電","54","/可愛","21","/豬頭","46","/咖啡","60","/哈欠","104","/鄙視","105","/委屈","106","/快哭了","107","/陰險","108","/親親","109","/嚇","110","/可憐","111","/菜刀","112","/啤酒","113","/籃球","114","/乒乓","115","/示愛","116","/瓢蟲","117","/抱拳","118","/勾引","119","/拳頭","120","/差勁","121","/愛你","122","/NO","123","/OK","124","/轉圈","125","/磕頭","126","/回頭","127","/跳繩","128","/揮手","129","/激動","130","/街舞","131","/獻吻","132","/左太極","133","/右太極","134","/吐","19","/蛋糕","53","/呲牙","13","/咒罵","31","/足球","57","/噓","33","/困","25","/大兵","29","/大哭","9","/強","76","/奮鬥","30","/擁抱","49","/害羞","6","/尷尬","10","/右哼哼","103","/慪火","86","/勝利","79","/得意","4","/驚訝","14","/心碎","67","/驚恐","26","/微笑","0","/憨笑","28","/抓狂","18","/折磨","35","/發抖","41","/握手","78","/飛吻","85","/鼓掌","99","/撇嘴","1","/敲打","38","/暈","34","/月亮","75","/流汗","27","/流淚","5","/糗大了","100","/愛心","66","/左哼哼","102","/玫瑰","63","/疑問","32","/白眼","22","/睡","8","/冷汗","96","/示愛","65","/弱","77","/跳跳","43","/色","2","/炸彈","55","/壞笑","101","/衰","36","/刀","56","/調皮","12","/摳鼻","98","/酷","16","/禮物","69","/閉嘴","7","/難過","15","/饑餓","24","/飯","61","/骷髏","37","/愛情","42"};
private int[] mSmileyIds = null;
private String[] mSmileyTexts = null;
public static SmileyParser getInstance() {
if (sInstance == null) {
sInstance = new SmileyParser(GameDataMgr.getInstance().getActivity());

}

return sInstance;
}
private SmileyParser(Context context) {
// TODO Auto-generated constructor stub
mContext = context;
initSmileyIds();
mPattern = buildPattern();
mSmileyTextToId = buildSmileyRes();
}

private void initSmileyIds(){
mSmileyIds = new int[mSmileyArrays.length / 2];
mSmileyTexts = new String[mSmileyArrays.length /2];
for (int i = 0; i < mSmileyArrays.length / 2; i++) {
mSmileyTexts[i] = mSmileyArrays[i*2];
mSmileyIds[i] = Integer.parseInt(mSmileyArrays[i*2 + 1]);
}
}

public int[] getSmileyIDs(){
return mSmileyIds;
}

public int getSmileyResourceId(int smileyId){
String idString = "face_" + Integer.toString(smileyId);

int id = getResId(idString, mContext, R.drawable.class);

return id;
}

public static int getResId(String variableName, Context context, Class<?> c) {

   try {
       Field idField = c.getDeclaredField(variableName);
       return idField.getInt(idField);
   } catch (Exception e) {
       e.printStackTrace();
       return -1;
   }
}

public String[] getSmileyTexts(){
return mSmileyTexts;
}

Drawable getSmileyDrawable(int id){
Drawable drawable = null;
drawable = mContext.getResources().getDrawable(getSmileyResourceId(id));

return drawable;

}

/**
* 建立String - Id的對應關系
*/
private HashMap<String, Integer> buildSmileyRes(){

HashMap<String, Integer> smileyTextToId = new HashMap<String, Integer>(mSmileyIds.length);
for(int i = 0;i < mSmileyIds.length;++i){
smileyTextToId.put(mSmileyTexts[i], mSmileyIds[i]);
}

return smileyTextToId;
}

/**
* 建立匹配用的正則表達式
* @return
*/
private Pattern buildPattern(){
StringBuilder builder = new StringBuilder(mSmileyTexts.length * 3);
builder.append('(');
for (String  s:  mSmileyTexts) {
builder.append(Pattern.quote(s));
builder.append('|');
}

builder.replace(builder.length() - 1, builder.length(), ")");

return Pattern.compile(builder.toString());
}

/**
* 把文字轉換為圖片
* @param text
* @return
*/
public Spannable addSmileySpans(CharSequence text){
SpannableStringBuilder spBuilder = new SpannableStringBuilder(text);

Matcher matcher = mPattern.matcher(text);

while (matcher.find()) {
int id = mSmileyTextToId.get(matcher.group());
matcher.start(),matcher.end(),Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
spBuilder.setSpan(new ImageSpan(mContext,getSmileyResourceId(id),ImageSpan.ALIGN_BASELINE),  matcher.start(),matcher.end(),Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

}

return spBuilder;
}
}

實現過程中遇到個小問題：往TextView中添加表情時，當文本既有表情也有文字時，顯示是正常的，但是當文本中只有表情時，發現表情顯示會偏上，而且上面有一部分被截斷。

TextView布局如下：
代碼如下：

<TextView

android:id="@+id/comment_item_content"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dp"

android:layout_marginBottom="10dp"

android:textSize="16sp"

android:textColor="#333333"

/>

解決方法：這裡的問題應該是TextView在判斷行距的時候是根據字體來判斷的，但是當文本是表情的時候這個判斷有些問題，導致行距過小，所以顯示表情的時候就截斷了，解決方法是設置一下TextView的最小高度，同時要指定文本向下對齊。另外在創建ImagePan的時候如果指定ImageSpan.ALIGN_BOTTOM對齊方式一般是不會出現這個問題的，但是這種方式下表情顯示會偏下。

修改後TextView布局如下：
代碼如下：

<TextView

android:id="@+id/comment_item_content"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dp"

android:layout_marginBottom="10dp"

android:textSize="16sp"

android:textColor="#333333"

android:minHeight="25dp"

android:gravity="bottom"

/>