样式EditText内容'即时'？

Question

我正在使用Android中的富文本编辑器.基本上它有粗体,斜体和链接按钮,它们与EditText相关联,以改变内容的样式.如果您首先选择要设置样式的文本,然后使用此方法选择按钮,我可以使用它:http://developer.android.com/guide/appendix/faq/commontasks.html#selectingtext.

我要做的是让它像富文本编辑器一样工作,你可以使用按钮作为切换来根据需要设置文本样式,然后再次单击切换以停止使用样式.所以如果我想输入' 注意这个!'以粗体显示,我会点击'B'按钮,然后开始输入文字,我输入的所有内容都是粗体,直到我再次点击'B'按钮.

关于如何解决这个问题的任何想法？我希望我已经足够清楚了:)

Answer 1

对于那些感兴趣的人,我通过在按下ToggleButton时保存光标位置(下面的'styleStart'变量)来实现这一点,然后当用户键入更多字符时,我实际上用removeSpan()删除匹配的StyleSpan,然后重新使用保存的原始光标位置+当前键入的字符长度,使用setSpan()将其添加回来.

您还需要跟踪用户是否更改光标位置,以便不设置您不想要的文本样式.这是TextWatcher代码:

final EditText contentEdit = (EditText) findViewById(R.id.content);
        contentEdit.addTextChangedListener(new TextWatcher() { 
            public void afterTextChanged(Editable s) { 
                //add style as the user types if a toggle button is enabled
                ToggleButton boldButton = (ToggleButton) findViewById(R.id.bold);
                ToggleButton emButton = (ToggleButton) findViewById(R.id.em);
                ToggleButton bquoteButton = (ToggleButton) findViewById(R.id.bquote);
                ToggleButton underlineButton = (ToggleButton) findViewById(R.id.underline);
                ToggleButton strikeButton = (ToggleButton) findViewById(R.id.strike);
                int position = Selection.getSelectionStart(contentEdit.getText());
                if (position < 0){
                    position = 0;
                }

                if (position > 0){

                    if (styleStart > position || position > (cursorLoc + 1)){
                        //user changed cursor location, reset
                        styleStart = position - 1;
                    }

                    cursorLoc = position;

                    if (boldButton.isChecked()){  
                        StyleSpan[] ss = s.getSpans(styleStart, position, StyleSpan.class);

                        for (int i = 0; i < ss.length; i++) {
                            if (ss[i].getStyle() == android.graphics.Typeface.BOLD){
                                s.removeSpan(ss[i]);
                            }
                        }
                        s.setSpan(new StyleSpan(android.graphics.Typeface.BOLD), styleStart, position, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                    }
                    if (emButton.isChecked()){
                        StyleSpan[] ss = s.getSpans(styleStart, position, StyleSpan.class);

                        boolean exists = false;
                        for (int i = 0; i < ss.length; i++) {
                            if (ss[i].getStyle() == android.graphics.Typeface.ITALIC){
                                s.removeSpan(ss[i]);
                            }
                        }
                        s.setSpan(new StyleSpan(android.graphics.Typeface.ITALIC), styleStart, position, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                    }
                    if (bquoteButton.isChecked()){

                        QuoteSpan[] ss = s.getSpans(styleStart, position, QuoteSpan.class);

                        for (int i = 0; i < ss.length; i++) {
                                s.removeSpan(ss[i]);
                        }
                        s.setSpan(new QuoteSpan(), styleStart, position, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                    }
                    if (underlineButton.isChecked()){
                        UnderlineSpan[] ss = s.getSpans(styleStart, position, UnderlineSpan.class);

                        for (int i = 0; i < ss.length; i++) {
                                s.removeSpan(ss[i]);
                        }
                        s.setSpan(new UnderlineSpan(), styleStart, position, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                    }
                    if (strikeButton.isChecked()){
                        StrikethroughSpan[] ss = s.getSpans(styleStart, position, StrikethroughSpan.class);

                        for (int i = 0; i < ss.length; i++) {
                                s.removeSpan(ss[i]);
                        }
                        s.setSpan(new StrikethroughSpan(), styleStart, position, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                    }
                }
            } 
            public void beforeTextChanged(CharSequence s, int start, int count, int after) { 
                    //unused
            } 
            public void onTextChanged(CharSequence s, int start, int before, int count) { 
                        //unused
                } 
});

这是ToggleButton点击操作之一:

final ToggleButton boldButton = (ToggleButton) findViewById(R.id.bold);   

            boldButton.setOnClickListener(new Button.OnClickListener() {
                public void onClick(View v) {

                    EditText contentText = (EditText) findViewById(R.id.content);

                    int selectionStart = contentText.getSelectionStart();

                    styleStart = selectionStart;

                    int selectionEnd = contentText.getSelectionEnd();

                    if (selectionStart > selectionEnd){
                        int temp = selectionEnd;
                        selectionEnd = selectionStart;
                        selectionStart = temp;
                    }


                    if (selectionEnd > selectionStart)
                    {
                        Spannable str = contentText.getText();
                        StyleSpan[] ss = str.getSpans(selectionStart, selectionEnd, StyleSpan.class);

                        boolean exists = false;
                        for (int i = 0; i < ss.length; i++) {
                            if (ss[i].getStyle() == android.graphics.Typeface.BOLD){
                                str.removeSpan(ss[i]);
                                exists = true;
                            }
                        }

                        if (!exists){
                            str.setSpan(new StyleSpan(android.graphics.Typeface.BOLD), selectionStart, selectionEnd, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
                        }

                        boldButton.setChecked(false);
                    }
                }
        });

可能有一个更好的解决方案,如果你有一个,很高兴听到它!

Answer 2

您可以在使用a TextWatcher和addTextChangedListener()方法键入的每个字符后更新样式.

好的,这只是裸骨的示例代码.

int mStart = -1;

// Bold onClickListener
public void onClick(View view)
{
    if(mStart == -1) mStart = mEditText.getText().length();
    else mStart = -1;
}

// TextWatcher
onTextChanged(CharSequence s, int start, int before, int count)
{
    if(mStart > 0)
    {
        int end = mEditText.getText().length();
        mEditText.getText().setSpan(new StyleSpan(android.graphics.Typeface.BOLD), mStart, end - mStart, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    }
}