让你的EditText删除表情比微信更高效--记一次android性能分析优化实战

    setOnKeyListener(new OnKeyListener() {
      @Override
      public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_DEL && event.getAction() == KeyEvent.ACTION_DOWN) {
          return onDeleteEvent();
        }
        return false;
      }
    });

  private boolean onDeleteEvent() {
    int selectionStart = getSelectionStart();
    int selectionEnd = getSelectionEnd();
    if (selectionEnd != selectionStart) {
      return false;
    }
    SpData[] spDatas = getSpDatas();
    for (SpData spData : spDatas) {
      if (selectionStart == spData.end) {
        Editable editable = getText();
        editable.delete(spData.start, spData.end);
        return true;
      }

    }
    return false;
  }

                if (spanned == null) {
                    spanEnd = paraEnd;
                    int spanLen = spanEnd - spanStart;
                    measured.addStyleRun(paint, spanLen, fm);
                } else {
                    spanEnd = spanned.nextSpanTransition(spanStart, paraEnd,
                            MetricAffectingSpan.class);
                    int spanLen = spanEnd - spanStart;
                    MetricAffectingSpan[] spans =
                            spanned.getSpans(spanStart, spanEnd, MetricAffectingSpan.class);
                    spans = TextUtils.removeEmptySpans(spans, spanned, MetricAffectingSpan.class);
                    measured.addStyleRun(paint, spans, spanLen, fm);
                }

  private boolean onDeleteEvent() {
    int selectionStart = getSelectionStart();
    int selectionEnd = getSelectionEnd();
    if (selectionEnd != selectionStart) {
      return false;
    }
    SpData[] spDatas = getSpDatas();
    for (int i = 0; i < spDatas.length; i++) {
      SpData spData = spDatas[i];
      if (selectionStart == spData.end) {
        Editable editable = getText();
        SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(editable);
        spannableStringBuilder.delete(spData.start, spData.end);
        GifTextUtil.setText(this, spannableStringBuilder);
        setSelection(spData.start);
        return true;
      }

    }
    return false;
  }

            case DO_SEND_KEY_EVENT: {
                InputConnection ic = getInputConnection();
                if (ic == null || !isActive()) {
                    Log.w(TAG, "sendKeyEvent on inactive InputConnection");
                    return;
                }
                ic.sendKeyEvent((KeyEvent)msg.obj);
                onUserAction();
                return;
            }

final class ImageEditableFactory extends Factory {

  private static final Object sInstanceLock = new Object();
  @GuardedBy("sInstanceLock")
  private static volatile Factory sInstance;
  @Nullable
  private static Class<?> sWatcherClass;

  @SuppressLint({"PrivateApi"})
  private ImageEditableFactory() {
    try {
      String className = "android.text.DynamicLayout$ChangeWatcher";
      sWatcherClass = this.getClass().getClassLoader().loadClass(className);
    } catch (Throwable var2) {
      ;
    }

  }

  public static Factory getInstance() {
    if (sInstance == null) {
      Object var0 = sInstanceLock;
      synchronized (sInstanceLock) {
        if (sInstance == null) {
          sInstance = new ImageEditableFactory();
        }
      }
    }

    return sInstance;
  }

  public Editable newEditable(@NonNull CharSequence source) {
    return (Editable) (sWatcherClass != null ? SpannableBuilder.create(sWatcherClass, source)
        : super.newEditable(source));
  }
}

private static class WatcherWrapper implements TextWatcher, SpanWatcher {

    private final Object mObject;
    private final AtomicInteger mBlockCalls = new AtomicInteger(0);

    WatcherWrapper(Object object) {
      this.mObject = object;
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
      ((TextWatcher) mObject).beforeTextChanged(s, start, count, after);
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
      ((TextWatcher) mObject).onTextChanged(s, start, before, count);
    }

    @Override
    public void afterTextChanged(Editable s) {
      ((TextWatcher) mObject).afterTextChanged(s);
    }

    @Override
    public void onSpanAdded(Spannable text, Object what, int start, int end) {
      if (mBlockCalls.get() > 0 && isImageSpan(what)) {
        return;
      }
      ((SpanWatcher) mObject).onSpanAdded(text, what, start, end);
    }

    @Override
    public void onSpanRemoved(Spannable text, Object what, int start, int end) {
      if (mBlockCalls.get() > 0 && isImageSpan(what)) {
        return;
      }
      ((SpanWatcher) mObject).onSpanRemoved(text, what, start, end);
    }

    @Override
    public void onSpanChanged(Spannable text, Object what, int ostart, int oend, int nstart,
        int nend) {
      if (mBlockCalls.get() > 0 && isImageSpan(what)) {
        return;
      }
      ((SpanWatcher) mObject).onSpanChanged(text, what, ostart, oend, nstart, nend);
    }

    final void blockCalls() {
      mBlockCalls.incrementAndGet();
    }

    final void unblockCalls() {
      mBlockCalls.decrementAndGet();
    }

    private boolean isImageSpan(final Object span) {
      return span instanceof ImageSpan;
    }
  }

setEditableFactory(ImageEditableFactory.getInstance());