前言
相信大家應該都有所體會，對于一個社交性質的App,業務上少不了給一段文本加上@功能、話題功能，或者是評論上要高亮人名的需求。當然，Android為我們提供了ClickableSpan，用于解決TextView部分內容可點擊的問題，但卻附加了一堆的坑點：
這些默認的表現會使得添加 ClickableSpan 后會出現各種不符合預期的問題，因此我們需要對其進行封裝。
據個人使用經驗，封裝后應該能夠方便開發實現以下行為：
對于第三點，需要解釋下TextView是否消耗事件的影響
用一張圖來闡述下我們的目的。我們開發過程中，可能將點擊事件加在TextView上，也可能將點擊行為添加在TextView的父元素上，例如評論一般是點擊整個評論item就可以觸發回復。 如果我們把點擊事件加在TextView的父元素上，那么我們期待的是點擊TextView的綠色區域應該也要響應點擊事件，但現實總是殘酷的，如果TextView調用了setMovementMethod, 點擊綠色區域將不會有任何反應，因為時間被TextView消耗了，并不會傳遞到TextView的父元素上。
那我們來一步一步看如何實現這幾個問題。
首先我們定義一個接口 ITouchableSpan, 用于抽象press和點擊:
public interface ITouchableSpan { void setPressed(boolean pressed); void onClick(View widget);}然后建立一個 ClickableSpan的子類 QMUITouchableSpan 來擴充它的表現：
public abstract class QMUITouchableSpan extends ClickableSpan implements ITouchableSpan { private boolean mIsPressed; @ColorInt private int mNormalBackgroundColor; @ColorInt private int mPressedBackgroundColor; @ColorInt private int mNormalTextColor; @ColorInt private int mPressedTextColor; private boolean mIsNeedUnderline = false; public abstract void onSpanClick(View widget); @Override public final void onClick(View widget) { if (ViewCompat.isAttachedToWindow(widget)) { onSpanClick(widget); } } public QMUITouchableSpan(@ColorInt int normalTextColor, @ColorInt int pressedTextColor, @ColorInt int normalBackgroundColor, @ColorInt int pressedBackgroundColor) { mNormalTextColor = normalTextColor; mPressedTextColor = pressedTextColor; mNormalBackgroundColor = normalBackgroundColor; mPressedBackgroundColor = pressedBackgroundColor; } // .... get/set ... public void setPressed(boolean isSelected) { mIsPressed = isSelected; } public boolean isPressed() { return mIsPressed; } @Override public void updateDrawState(TextPaint ds) { // 通過updateDrawState來更新字體顏色和背景色 ds.setColor(mIsPressed ? mPressedTextColor : mNormalTextColor); ds.bgColor = mIsPressed ? mPressedBackgroundColor : mNormalBackgroundColor; ds.setUnderlineText(mIsNeedUnderline); }}然后我們要把press狀態和點擊行為傳遞給QMUITouchableSpan,這一層我們可以通過重載 LinkMovementMethod去解決：
public class QMUILinkTouchMovementMethod extends LinkMovementMethod { @Override public boolean onTouchEvent(TextView widget, Spannable buffer, MotionEvent event) { return sHelper.onTouchEvent(widget, buffer, event) || Touch.onTouchEvent(widget, buffer, event); } public static MovementMethod getInstance() { if (sInstance == null) sInstance = new QMUILinkTouchMovementMethod(); return sInstance; } private static QMUILinkTouchMovementMethod sInstance; private static QMUILinkTouchDecorHelper sHelper = new QMUILinkTouchDecorHelper();}對TextView使用 setMovementMethod 后，TextView的 onTouchEvent 中會調用到 LinkMovementMethod的onTouchEvent，并且會傳入Spannable,這是一個去處理Spannable數據的好hook點。 我們抽取一個 QMUILinkTouchDecorHelper 用于處理公共邏輯，因為LinkMovementMethod存在多個行為各異的子類。
public class QMUILinkTouchDecorHelper { private ITouchableSpan mPressedSpan; public boolean onTouchEvent(TextView textView, Spannable spannable, MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN) { mPressedSpan = getPressedSpan(textView, spannable, event); if (mPressedSpan != null) { mPressedSpan.setPressed(true); Selection.setSelection(spannable, spannable.getSpanStart(mPressedSpan), spannable.getSpanEnd(mPressedSpan)); } if (textView instanceof QMUISpanTouchFixTextView) { QMUISpanTouchFixTextView tv = (QMUISpanTouchFixTextView) textView; tv.setTouchSpanHint(mPressedSpan != null); } return mPressedSpan != null; } else if (event.getAction() == MotionEvent.ACTION_MOVE) { ITouchableSpan touchedSpan = getPressedSpan(textView, spannable, event); if (mPressedSpan != null && touchedSpan != mPressedSpan) { mPressedSpan.setPressed(false); mPressedSpan = null; Selection.removeSelection(spannable); } return mPressedSpan != null; } else if (event.getAction() == MotionEvent.ACTION_UP) { boolean touchSpanHint = false; if (mPressedSpan != null) { touchSpanHint = true; mPressedSpan.setPressed(false); mPressedSpan.onClick(textView); } mPressedSpan = null; Selection.removeSelection(spannable); return touchSpanHint; } else { if (mPressedSpan != null) { mPressedSpan.setPressed(false); } Selection.removeSelection(spannable); return false; } } public ITouchableSpan getPressedSpan(TextView textView, Spannable spannable, MotionEvent event) { int x = (int) event.getX(); int y = (int) event.getY(); x -= textView.getTotalPaddingLeft(); y -= textView.getTotalPaddingTop(); x += textView.getScrollX(); y += textView.getScrollY(); Layout layout = textView.getLayout(); int line = layout.getLineForVertical(y); int off = layout.getOffsetForHorizontal(line, x); ITouchableSpan[] link = spannable.getSpans(off, off, ITouchableSpan.class); ITouchableSpan touchedSpan = null; if (link.length > 0) { touchedSpan = link[0]; } return touchedSpan; }}上述的很多行為直接取自官方的LinkTouchMovementMethod，然后做了相應的修改。完成這些，我們才僅僅能做到我們想要的第一步而已。
接下來我們看如何處理TextView的click與press與 QMUITouchableSpan 沖突的問題。 這一步我們需要建立一個TextView的子類QMUISpanTouchFixTextView去處理相關細節。
第一步我們需要判斷是否是點擊到了QMUITouchableSpan, 這個判斷可以放在 QMUILinkTouchDecorHelper#onTouchEvent中完成， 在onTouchEvent中補充以下代碼：
public boolean onTouchEvent(TextView textView, Spannable spannable, MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN) { // ... if (textView instanceof QMUISpanTouchFixTextView) { QMUISpanTouchFixTextView tv = (QMUISpanTouchFixTextView) textView; tv.setTouchSpanHint(mPressedSpan != null); } return mPressedSpan != null; } else if (event.getAction() == MotionEvent.ACTION_MOVE) { // ... if (textView instanceof QMUISpanTouchFixTextView) { QMUISpanTouchFixTextView tv = (QMUISpanTouchFixTextView) textView; tv.setTouchSpanHint(mPressedSpan != null); } return mPressedSpan != null; } else if (event.getAction() == MotionEvent.ACTION_UP) { // ... Selection.removeSelection(spannable); if (textView instanceof QMUISpanTouchFixTextView) { QMUISpanTouchFixTextView tv = (QMUISpanTouchFixTextView) textView; tv.setTouchSpanHint(touchSpanHint); } return touchSpanHint; } else { // ... if (textView instanceof QMUISpanTouchFixTextView) { QMUISpanTouchFixTextView tv = (QMUISpanTouchFixTextView) textView; tv.setTouchSpanHint(false); } // ... return false; }}這個時候我們在 QMUISpanTouchFixTextView就可以通過是否點擊到QMUITouchableSpan來決定不同行為了，對于點擊是非常好處理的，代碼如下：
@Overridepublic boolean performClick() { if (!mTouchSpanHint) { return super.performClick(); } return false;}對于press行為，就會有點棘手，因為setPress在 onTouchEvent多次調用，而且在QMUILinkTouchDecorHelper#onTouchEvent前就會被調用到，所以不能簡單的用mTouchSpanHint這個變量來管理。來看看我給出的方案：
// 記錄每次真正傳入的press，每次更改mTouchSpanHint，需要再調用一次setPressed，確保press狀態正確// 第一步： 用一個變量記錄setPress傳入的值，這個是TextView真正的press值private boolean mIsPressedRecord = false;// 第二步，onTouchEvent在調用super前將mTouchSpanHint設為true，這會使得QMUILinkTouchDecorHelper#onTouchEvent的press行為失效，參考第三步@Overridepublic boolean onTouchEvent(MotionEvent event) { if (!(getText() instanceof Spannable)) { return super.onTouchEvent(event); } mTouchSpanHint = true; return super.onTouchEvent(event);}// 第三步： final掉setPressed，如果!mTouchSpanHint才調用super.setPressed，開一個onSetPressed給子類覆寫@Overridepublic final void setPressed(boolean pressed) { mIsPressedRecord = pressed; if (!mTouchSpanHint) { onSetPressed(pressed); }}protected void onSetPressed(boolean pressed) { super.setPressed(pressed);}// 第四步： 每次調用setTouchSpanHint是調用一次setPressed，并傳入mIsPressedRecord，確保press狀態的統一public void setTouchSpanHint(boolean touchSpanHint) { if (mTouchSpanHint != touchSpanHint) { mTouchSpanHint = touchSpanHint; setPressed(mIsPressedRecord); }}這幾個步驟相互耦合，靜下心好好理解下。這樣就順利的解決了第二個問題。那么我們來看看如何消除 MovementMethod造成TextView對事件的消耗行為。
調用 setMovementMethod為何會使得TextView必然消耗事件呢？我們可以看看源碼：
public final void setMovementMethod(MovementMethod movement) { if (mMovement != movement) { mMovement = movement; if (movement != null && !(mText instanceof Spannable)) { setText(mText); } fixFocusableAndClickableSettings(); // SelectionModifierCursorController depends on textCanBeSelected, which depends on // mMovement if (mEditor != null) mEditor.prepareCursorControllers(); }}private void fixFocusableAndClickableSettings() { if (mMovement != null || (mEditor != null && mEditor.mKeyListener != null)) { setFocusable(true); setClickable(true); setLongClickable(true); } else { setFocusable(false); setClickable(false); setLongClickable(false); }}原來設置MovementMethod后會把clickable,longClickable和focusable都設置為true,這樣必然TextView會消耗事件了。因此我們想到的解決方案就是：如果我們想不讓TextView消耗事件，那么我們就在 setMovementMethod之后再改一次clickable,longClickable和focusable。
public void setShouldConsumeEvent(boolean shouldConsumeEvent) { mShouldConsumeEvent = shouldConsumeEvent; setFocusable(shouldConsumeEvent); setClickable(shouldConsumeEvent); setLongClickable(shouldConsumeEvent);}public void setMovementMethodCompat(MovementMethod movement){ setMovementMethod(movement); if(!mShouldConsumeEvent){ setShouldConsumeEvent(false); }}僅僅這樣還不夠，我們還必須在 onTouchEvent里面返回false:
@Overridepublic boolean onTouchEvent(MotionEvent event) { if (!(getText() instanceof Spannable)) { return super.onTouchEvent(event); } mTouchSpanHint = true; // 調用super.onTouchEvent,會走到QMUILinkTouchMovementMethod // 會走到QMUILinkTouchMovementMethod#onTouchEvent會修改mTouchSpanHint boolean ret = super.onTouchEvent(event); if(!mShouldConsumeEvent){ return mTouchSpanHint; } return ret;}經過層層fix，我們終于可以給出一份不錯的封裝代碼提供給業務方使用了：
public class QMUISpanTouchFixTextView extends TextView { private boolean mTouchSpanHint; // 記錄每次真正傳入的press，每次更改mTouchSpanHint，需要再調用一次setPressed，確保press狀態正確 private boolean mIsPressedRecord = false; private boolean mShouldConsumeEvent = true; // TextView是否應該消耗事件 public QMUISpanTouchFixTextView(Context context) { this(context, null); } public QMUISpanTouchFixTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public QMUISpanTouchFixTextView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); setHighlightColor(Color.TRANSPARENT); setMovementMethod(QMUILinkTouchMovementMethod.getInstance()); } public void setShouldConsumeEvent(boolean shouldConsumeEvent) { mShouldConsumeEvent = shouldConsumeEvent; setFocusable(shouldConsumeEvent); setClickable(shouldConsumeEvent); setLongClickable(shouldConsumeEvent); } public void setMovementMethodCompat(MovementMethod movement){ setMovementMethod(movement); if(!mShouldConsumeEvent){ setShouldConsumeEvent(false); } } @Override public boolean onTouchEvent(MotionEvent event) { if (!(getText() instanceof Spannable)) { return super.onTouchEvent(event); } mTouchSpanHint = true; // 調用super.onTouchEvent,會走到QMUILinkTouchMovementMethod // 會走到QMUILinkTouchMovementMethod#onTouchEvent會修改mTouchSpanHint boolean ret = super.onTouchEvent(event); if(!mShouldConsumeEvent){ return mTouchSpanHint; } return ret; } public void setTouchSpanHint(boolean touchSpanHint) { if (mTouchSpanHint != touchSpanHint) { mTouchSpanHint = touchSpanHint; setPressed(mIsPressedRecord); } } @Override public boolean performClick() { if (!mTouchSpanHint && mShouldConsumeEvent) { return super.performClick(); } return false; } @Override public boolean performLongClick() { if (!mTouchSpanHint && mShouldConsumeEvent) { return super.performLongClick(); } return false; } @Override public final void setPressed(boolean pressed) { mIsPressedRecord = pressed; if (!mTouchSpanHint) { onSetPressed(pressed); } } protected void onSetPressed(boolean pressed) { super.setPressed(pressed); }}總結
以上就是這篇文章的全部內容了，希望本文的內容對給位Android開發者們能帶來一定的幫助，如果有疑問大家可以留言交流，謝謝大家對武林網的支持。
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