可折叠的TextView

1、可折叠的TextView，做学习保留,引用：

https://github.com/hymanme/ExpandTextView

public class ExpandTextView extends LinearLayout implements View.OnClickListener {
    public static final String TAG = "ExpandTextView";


    public static final int DEFAULT_TITLE_TEXT_COLOR = 0X8A000000;
    public static final int DEFAULT_CONTENT_TEXT_COLOR = 0XDE000000;
    public static final int DEFAULT_HINT_TEXT_COLOR = 0XDE000000;
    public static final int DEFAULT_MIN_LINES = 4;
    public static final int DEFAULT_TITLE_TEXT_SIZE = 16;
    public static final int DEFAULT_CONTENT_TEXT_SIZE = 14;
    public static final int DEFAULT_HINT_TEXT_SIZE = 12;
    public static final int DEFAULT_ANIMATION_DURATION = 600;

    private Context mContext;
    //标题
    private String title;
    //内容文字
    private String content;
    //展开后显示的文字
    private String foldHint;
    //折叠起来后显示的文字
    private String expandHint;
    //标题文字颜色
    private int titleTextColor;
    //内容文字颜色
    private int contentTextColor;
    //查看更多文字颜色
    private int hintTextColor;
    //查看更多前面显示的小图标
    private Drawable indicateImage;
    //内容区域最少显示几行文字
    private int minVisibleLines;
    //标题字体大小
    private float titleTextSize;
    //内容字体大小
    private float contentTextSize;
    //提示字体大小
    private float hintTextSize;
    //展开和折叠动画持续时间
    private int animationDuration;

    private TextView mTitleView;
    private TextView mContentView;
    private TextView mHintView;
    private ImageView mIndicateImage;
    private RelativeLayout mShowMore;
    private TextView copy;

    private OnReadMoreClickListener mListener;

    //      是否已经展开
    private boolean flag;

    public ExpandTextView(Context context) {
        this(context, null);
    }

    public ExpandTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public ExpandTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.mContext = context;
        setOrientation(VERTICAL);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ExpandTextView);
        title = a.getString(R.styleable.ExpandTextView_titleText);
        content = a.getString(R.styleable.ExpandTextView_contentText);
        foldHint = a.getString(R.styleable.ExpandTextView_foldHint);
        expandHint = a.getString(R.styleable.ExpandTextView_expandHint);
        titleTextColor = a.getColor(R.styleable.ExpandTextView_textTitleColor, DEFAULT_TITLE_TEXT_COLOR);
        contentTextColor = a.getColor(R.styleable.ExpandTextView_textContentColor, DEFAULT_CONTENT_TEXT_COLOR);
        hintTextColor = a.getColor(R.styleable.ExpandTextView_textHintColor, DEFAULT_HINT_TEXT_COLOR);
        indicateImage = a.getDrawable(R.styleable.ExpandTextView_indicateImage);
        minVisibleLines = a.getInt(R.styleable.ExpandTextView_minVisibleLines, DEFAULT_MIN_LINES);
        titleTextSize = a.getDimension(R.styleable.ExpandTextView_titleTextSize, sp2px(mContext, DEFAULT_TITLE_TEXT_SIZE));
        contentTextSize = a.getDimension(R.styleable.ExpandTextView_contentTextSize, sp2px(mContext, DEFAULT_CONTENT_TEXT_SIZE));
        hintTextSize = a.getDimension(R.styleable.ExpandTextView_hintTextSize, sp2px(mContext, DEFAULT_HINT_TEXT_SIZE));
        animationDuration = a.getInt(R.styleable.ExpandTextView_animationDuration, DEFAULT_ANIMATION_DURATION);

        a.recycle();
        init();
    }

    /**
     * 初始化
     */
    private void init() {
        View.inflate(mContext, R.layout.expand_text_view, this);
        mTitleView = (TextView) findViewById(R.id.tv_title);
        mContentView = (TextView) findViewById(R.id.tv_content);
        mHintView = (TextView) findViewById(R.id.tv_more_hint);
        mIndicateImage = (ImageView) findViewById(R.id.iv_arrow_more);
        mShowMore = (RelativeLayout) findViewById(R.id.rl_show_more);

        mTitleView.setText(title);
        mTitleView.setTextSize(TypedValue.COMPLEX_UNIT_PX, titleTextSize);
        mTitleView.setTextColor(titleTextColor);

        mContentView.setText(content);
        mContentView.setTextSize(TypedValue.COMPLEX_UNIT_PX, contentTextSize);
        mContentView.setTextColor(contentTextColor);

        mHintView.setText(expandHint);
        mHintView.setTextSize(TypedValue.COMPLEX_UNIT_PX, hintTextSize);
        mHintView.setTextColor(hintTextColor);

        if (indicateImage == null) {
            indicateImage = getResources().getDrawable(R.drawable.ic_arrow_down_light_round);
        }
        mIndicateImage.setImageDrawable(indicateImage);
        mShowMore.setOnClickListener(this);
        ViewGroup.LayoutParams layoutParams = mContentView.getLayoutParams();
        layoutParams.height = getMinMeasureHeight();
        mContentView.setLayoutParams(layoutParams);
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
        mTitleView.setText(title);
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
        mContentView.setText(content);
    }

    public String getFoldHint() {
        return foldHint;
    }

    public void setFoldHint(String foldHint) {
        this.foldHint = foldHint;
    }

    public String getExpandHint() {
        return expandHint;
    }

    public void setExpandHint(String expandHint) {
        this.expandHint = expandHint;
    }

    public int getTitleTextColor() {
        return titleTextColor;
    }

    public void setTitleTextColor(@ColorInt int titleTextColor) {
        this.titleTextColor = titleTextColor;
        mTitleView.setTextColor(titleTextColor);
    }

    public int getContentTextColor() {
        return contentTextColor;
    }

    public void setContentTextColor(@ColorInt int contentTextColor) {
        this.contentTextColor = contentTextColor;
        mContentView.setTextColor(contentTextColor);
    }

    public int getHintTextColor() {
        return hintTextColor;
    }

    public void setHintTextColor(@ColorInt int hintTextColor) {
        this.hintTextColor = hintTextColor;
        mHintView.setTextColor(hintTextColor);
    }

    public Drawable getIndicateImage() {
        return indicateImage;
    }

    public void setIndicateImage(@DrawableRes Drawable indicateImage) {
        this.indicateImage = indicateImage;
        mIndicateImage.setImageDrawable(indicateImage);
    }

    public void setIndicateImage(@DrawableRes int indicateImageRes) {
        this.indicateImage = getResources().getDrawable(indicateImageRes);
        mIndicateImage.setImageDrawable(this.indicateImage);
    }

    public int getMinVisibleLines() {
        return minVisibleLines;
    }

    public void setMinVisibleLines(int minVisibleLines) {
        this.minVisibleLines = minVisibleLines;
        copy = null;
        ViewGroup.LayoutParams layoutParams = mContentView.getLayoutParams();
        layoutParams.height = getMinMeasureHeight();
        mContentView.setLayoutParams(layoutParams);
    }

    public float getTitleTextSize() {
        return titleTextSize;
    }

    /**
     * 设置字体大小
     *
     * @param titleTextSize sp为单位
     */
    public void setTitleTextSize(float titleTextSize) {
        this.titleTextSize = sp2px(mContext, titleTextSize);
        mTitleView.setTextSize(titleTextSize);
    }

    public float getContentTextSize() {
        return contentTextSize;
    }

    /**
     * 设置字体大小
     *
     * @param contentTextSize sp为单位
     */
    public void setContentTextSize(float contentTextSize) {
        this.contentTextSize = sp2px(mContext, contentTextSize);
        mContentView.setTextSize(contentTextSize);
        copy = null;
        ViewGroup.LayoutParams layoutParams = mContentView.getLayoutParams();
        layoutParams.height = getMinMeasureHeight();
        mContentView.setLayoutParams(layoutParams);
    }

    public float getHintTextSize() {
        return hintTextSize;
    }

    /**
     * 设置字体大小
     *
     * @param hintTextSize sp为单位
     */
    public void setHintTextSize(float hintTextSize) {
        this.hintTextSize = sp2px(mContext, hintTextSize);
        mHintView.setTextSize(hintTextSize);
    }

    public View getTitleView() {
        return mTitleView;
    }

    public int getAnimationDuration() {
        return animationDuration;
    }

    public void setAnimationDuration(int animationDuration) {
        this.animationDuration = animationDuration;
    }

    public OnReadMoreClickListener getReadMoreListener() {
        return mListener;
    }

    public void setOnReadMoreListener(OnReadMoreClickListener mListener) {
        this.mListener = mListener;
    }

    @Override
    public void onClick(View view) {
        if (view.getId() == R.id.rl_show_more) {
            expand();
        }
    }

    /**
     * 获取TextView最大高度
     *
     * @return int 最大测量高度
     */
    public int getMaxMeasureHeight() {
        int width = mContentView.getMeasuredWidth();
        int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
        int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(3000, View.MeasureSpec.AT_MOST);
        mContentView.measure(widthMeasureSpec, heightMeasureSpec);
        return mContentView.getMeasuredHeight();
    }

    /**
     * 获取TextView最小高度
     *
     * @return int 最小测量高度
     */
    public int getMinMeasureHeight() {
        if (copy == null) {
            copy = new TextView(mContext);
            copy.setTextSize(TypedValue.COMPLEX_UNIT_PX, contentTextSize);
            copy.setLineSpacing(dp2px(mContext, 6), 1.0f);
            copy.setLines(minVisibleLines);
        }
        int width = mContentView.getMeasuredWidth();
        int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
        int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(1000, View.MeasureSpec.AT_MOST);
        copy.setLayoutParams(mContentView.getLayoutParams());
        copy.measure(widthMeasureSpec, heightMeasureSpec);
        return copy.getMeasuredHeight();
    }

    /**
     * 折叠和展开
     */
    private void expand() {
        int startHeight;
        int targetHeight;
        if (!flag) {
            flag = true;
            startHeight = getMinMeasureHeight();
            targetHeight = getMaxMeasureHeight();
            if (targetHeight < startHeight) {
                targetHeight = startHeight;
            }
            mHintView.setText(foldHint);
            ObjectAnimator.ofFloat(mIndicateImage, "rotation", 0, 180).start();
            if (mListener != null) {
                mListener.onExpand();
            }
        } else {
            flag = false;
            startHeight = getMaxMeasureHeight();
            targetHeight = getMinMeasureHeight();
            if (startHeight < targetHeight) {
                startHeight = targetHeight;
            }
            mHintView.setText(expandHint);
            ObjectAnimator.ofFloat(mIndicateImage, "rotation", -180, 0).start();
            if (mListener != null) {
                mListener.onFold();
            }
        }
        if (animationDuration < 0) {
            animationDuration = DEFAULT_ANIMATION_DURATION;
        }
        final ViewGroup.LayoutParams layoutParams = mContentView.getLayoutParams();
        ValueAnimator animator = ValueAnimator.ofInt(startHeight, targetHeight);
        animator.setDuration(animationDuration);
        animator.setInterpolator(new AccelerateDecelerateInterpolator());
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                layoutParams.height = (int) animation.getAnimatedValue();
                mContentView.setLayoutParams(layoutParams);
            }
        });
        animator.start();
    }


    public interface OnReadMoreClickListener {
        //点击了展开
        void onExpand();

        //点击了折叠
        void onFold();
    }


    public static int dp2px(Context context, float dpVal) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                dpVal, context.getResources().getDisplayMetrics());
    }


    public static int sp2px(Context context, float spVal) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,
                spVal, context.getResources().getDisplayMetrics());
    }

    public static float px2dp(Context context, float pxVal) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (pxVal / scale);
    }

    public static float px2sp(Context context, float pxVal) {
        return (pxVal / context.getResources().getDisplayMetrics().scaledDensity);
    }

}

attrs.xml
<resources>
    <declare-styleable name="ExpandTextView">
        <attr name="titleText" format="reference|string" />
        <attr name="contentText" format="reference|string" />
        <attr name="foldHint" format="reference|string" />
        <attr name="expandHint" format="reference|string" />
        <attr name="textTitleColor" format="reference|color" />
        <attr name="textContentColor" format="reference|color" />
        <attr name="textHintColor" format="reference|color" />
        <attr name="indicateImage" format="reference" />
        <attr name="minVisibleLines" format="integer" />
        <attr name="titleTextSize" format="dimension" />
        <attr name="contentTextSize" format="dimension" />
        <attr name="hintTextSize" format="dimension" />
        <attr name="animationDuration" format="integer" />
    </declare-styleable>
</resources>

2、使用方法

etv.setContent("在这里输入textview需要显示的内容");
//        etv.setHintTextColor(Color.parseColor("#913242"));
        etv.setAnimationDuration(10000);
//        etv.setIndicateImage(R.drawable.aaa);
        etv.setOnReadMoreListener(new ExpandTextView.OnReadMoreClickListener() {
            @Override
            public void onExpand() {
                Toast.makeText(EnterActivity.this, "expand", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onFold() {
                Toast.makeText(EnterActivity.this, "fold", Toast.LENGTH_SHORT).show();
            }
        });

3、第二种，可设置展开全文的位置。

引用:
https://github.com/zly394/CollapsedTextView


public class CollapsedTextView extends AppCompatTextView implements View.OnClickListener {
    /**
     * 末尾省略号
     */
    private static final String ELLIPSE = "...";
    /**
     * 默认的折叠行数
     */
    public static final int COLLAPSED_LINES = 4;
    /**
     * 折叠时的默认文本
     */
    private static final String EXPANDED_TEXT = "展开全文";
    /**
     * 展开时的默认文本
     */
    private static final String COLLAPSED_TEXT = "收起全文";
    /**
     * 在文本末尾
     */
    public static final int END = 0;
    /**
     * 在文本下方
     */
    public static final int BOTTOM = 1;

    /**
     * 提示文字展示的位置
     */
    @IntDef({END, BOTTOM})
    @Retention(RetentionPolicy.SOURCE)
    public @interface TipsGravityMode {
    }

    /**
     * 折叠的行数
     */
    private int mCollapsedLines;
    /**
     * 折叠时的文本
     */
    private String mExpandedText;
    /**
     * 展开时的文本
     */
    private String mCollapsedText;
    /**
     * 折叠时的图片资源
     */
    private Drawable mExpandedDrawable;
    /**
     * 展开时的图片资源
     */
    private Drawable mCollapsedDrawable;
    /**
     * 原始的文本
     */
    private CharSequence mOriginalText;
    /**
     * TextView中文字可显示的宽度
     */
    private int mShowWidth;
    /**
     * 是否是展开的
     */
    private boolean mIsExpanded;
    /**
     * 提示文字位置
     */
    private int mTipsGravity;
    /**
     * 提示文字颜色
     */
    private int mTipsColor;
    /**
     * 提示文字是否显示下划线
     */
    private boolean mTipsUnderline;
    /**
     * 提示是否可点击
     */
    private boolean mTipsClickable;
    /**
     * 提示文本的点击事件
     */
    private ExpandedClickableSpan mClickableSpan = new ExpandedClickableSpan();
    /**
     * TextView的点击事件监听
     */
    private OnClickListener mListener;
    /**
     * 是否响应TextView的点击事件
     */
    private boolean mIsResponseListener = true;

    public CollapsedTextView(Context context) {
        this(context, null);
    }

    public CollapsedTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CollapsedTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs);
        // 使点击有效
        setMovementMethod(LinkMovementMethod.getInstance());
    }

    /**
     * 初始化属性
     */
    private void init(Context context, AttributeSet attrs) {
        if (attrs != null) {
            TypedArray typed = context.obtainStyledAttributes(attrs, R.styleable.CollapsedTextView);
            mCollapsedLines = typed.getInt(R.styleable.CollapsedTextView_collapsedLines, COLLAPSED_LINES);
            setExpandedText(typed.getString(R.styleable.CollapsedTextView_expandedText));
            setCollapsedText(typed.getString(R.styleable.CollapsedTextView_collapsedText));
            setExpandedDrawable(typed.getDrawable(R.styleable.CollapsedTextView_expandedDrawable));
            setCollapsedDrawable(typed.getDrawable(R.styleable.CollapsedTextView_collapsedDrawable));
            mTipsGravity = typed.getInt(R.styleable.CollapsedTextView_tipsGravity, END);
            mTipsColor = typed.getColor(R.styleable.CollapsedTextView_tipsColor, 0);
            mTipsUnderline = typed.getBoolean(R.styleable.CollapsedTextView_tipsUnderline, false);
            mTipsClickable = typed.getBoolean(R.styleable.CollapsedTextView_tipsClickable, true);
            typed.recycle();
        }
    }

    /**
     * 设置折叠行数
     *
     * @param collapsedLines 折叠行数
     */
    public void setCollapsedLines(@IntRange(from = 0) int collapsedLines) {
        this.mCollapsedLines = collapsedLines;
    }

    /**
     * 设置折叠时的提示文本
     *
     * @param expandedText 提示文本
     */
    public void setExpandedText(String expandedText) {
        this.mExpandedText = TextUtils.isEmpty(expandedText) ? EXPANDED_TEXT : expandedText;
    }

    /**
     * 设置展开时的提示文本
     *
     * @param collapsedText 提示文本
     */
    public void setCollapsedText(String collapsedText) {
        this.mCollapsedText = TextUtils.isEmpty(collapsedText) ? COLLAPSED_TEXT : collapsedText;
    }

    /**
     * 设置折叠时的提示图片
     *
     * @param resId 图片资源
     */
    public void setExpandedDrawableRes(@DrawableRes int resId) {
        setExpandedDrawable(ContextCompat.getDrawable(getContext(), resId));
    }

    /**
     * 设置折叠时的提示图片
     *
     * @param expandedDrawable 图片
     */
    public void setExpandedDrawable(Drawable expandedDrawable) {
        if (expandedDrawable != null) {
            this.mExpandedDrawable = expandedDrawable;
            this.mExpandedDrawable.setBounds(0, 0, mExpandedDrawable.getIntrinsicWidth(), mExpandedDrawable.getIntrinsicHeight());
        }
    }

    /**
     * 设置展开时的提示图片
     *
     * @param resId 图片资源
     */
    public void setCollapsedDrawableRes(@DrawableRes int resId) {
        setCollapsedDrawable(ContextCompat.getDrawable(getContext(), resId));
    }

    /**
     * 设置展开时的提示图片
     *
     * @param collapsedDrawable 图片
     */
    public void setCollapsedDrawable(Drawable collapsedDrawable) {
        if (collapsedDrawable != null) {
            this.mCollapsedDrawable = collapsedDrawable;
            this.mCollapsedDrawable.setBounds(0, 0, mCollapsedDrawable.getIntrinsicWidth(), mCollapsedDrawable.getIntrinsicHeight());
        }
    }

    /**
     * 设置提示的位置
     *
     * @param tipsGravity END 表示在文字末尾，BOTTOM 表示在文字下方
     */
    public void setTipsGravity(@TipsGravityMode int tipsGravity) {
        this.mTipsGravity = tipsGravity;
    }

    /**
     * 设置文字提示的颜色
     *
     * @param tipsColor 颜色
     */
    public void setTipsColor(@ColorInt int tipsColor) {
        this.mTipsColor = tipsColor;
    }

    /**
     * 设置提示文字是否有下划线
     *
     * @param tipsUnderline true 表示有下划线
     */
    public void setTipsUnderline(boolean tipsUnderline) {
        this.mTipsUnderline = tipsUnderline;
    }

    /**
     * 设置提示文字是否可点击
     *
     * @param tipsClickable true 表示可点击
     */
    public void setTipsClickable(boolean tipsClickable) {
        this.mTipsClickable = tipsClickable;
    }

    @Override
    public void setText(final CharSequence text, final BufferType type) {
        // 如果text为空或mCollapsedLines为0则直接显示
        if (TextUtils.isEmpty(text) || mCollapsedLines == 0) {
            super.setText(text, type);
        } else if (mIsExpanded) {
            // 保存原始文本，去掉文本末尾的空字符
            this.mOriginalText = trimFrom(text);
            formatExpandedText(type);
        } else {
            // 获取TextView中文字显示的宽度，需要在layout之后才能获取到，避免重复获取
            if (mShowWidth == 0) {
                getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                    @Override
                    public void onGlobalLayout() {
                        getViewTreeObserver().removeOnGlobalLayoutListener(this);
                        mShowWidth = getWidth() - getPaddingLeft() - getPaddingRight();
                        formatCollapsedText(type, text);
                    }
                });
            } else {
                formatCollapsedText(type, text);
            }
        }
    }

    /**
     * 格式化折叠时的文本
     *
     * @param type ref android.R.styleable#TextView_bufferType
     */
    private void formatCollapsedText(BufferType type, CharSequence text) {
        // 保存原始文本，去掉文本末尾的空字符
        this.mOriginalText = trimFrom(text);
        // 获取 layout，用于计算行数
        Layout layout = getLayout();
        // 调用 setText 用于重置 Layout
        if (layout == null || !layout.getText().equals(mOriginalText)) {
            super.setText(mOriginalText, type);
            layout = getLayout();
        }
        // 获取 paint，用于计算文字宽度
        TextPaint paint = getPaint();

        int line = layout.getLineCount();
        if (line <= mCollapsedLines) {
            super.setText(mOriginalText, type);
        } else {
            // 最后一行的开始字符位置
            int lastLineStart = layout.getLineStart(mCollapsedLines - 1);
            // 最后一行的结束字符位置
            int lastLineEnd = layout.getLineVisibleEnd(mCollapsedLines - 1);
            // 计算后缀的宽度
            int expandedTextWidth;
            if (mTipsGravity == END) {
                expandedTextWidth = (int) paint.measureText(ELLIPSE + " " + mExpandedText);
            } else {
                expandedTextWidth = (int) paint.measureText(ELLIPSE + " ");
            }
            // 最后一行的宽
            float lastLineWidth = layout.getLineWidth(mCollapsedLines - 1);
            // 如果大于屏幕宽度则需要减去部分字符
            if (lastLineWidth + expandedTextWidth > mShowWidth) {
                int cutCount = paint.breakText(mOriginalText, lastLineStart, lastLineEnd, false, expandedTextWidth, null);
                lastLineEnd -= cutCount;
            }
            // 因设置的文本可能是带有样式的文本，如SpannableStringBuilder，所以根据计算的字符数从原始文本中截取
            SpannableStringBuilder spannable = new SpannableStringBuilder();
            // 截取文本，还是因为原始文本的样式原因不能直接使用paragraphs中的文本
            CharSequence ellipsizeText = mOriginalText.subSequence(0, lastLineEnd);
            spannable.append(ellipsizeText);
            spannable.append(ELLIPSE);
            // 设置样式
            setSpan(spannable);
            super.setText(spannable, type);
        }
    }

    /**
     * 格式化展开式的文本，直接在后面拼接即可
     *
     * @param type
     */
    private void formatExpandedText(BufferType type) {
        SpannableStringBuilder spannable = new SpannableStringBuilder(mOriginalText);
        setSpan(spannable);
        super.setText(spannable, type);
    }

    /**
     * 设置提示的样式
     *
     * @param spannable 需修改样式的文本
     */
    private void setSpan(SpannableStringBuilder spannable) {
        Drawable drawable;
        // 根据提示文本需要展示的文字拼接不同的字符
        if (mTipsGravity == END) {
            spannable.append(" ");
        } else {
            spannable.append("\n");
        }
        int tipsLen;
        // 判断是展开还是收起
        if (mIsExpanded) {
            spannable.append(mCollapsedText);
            drawable = mCollapsedDrawable;
            tipsLen = mCollapsedText.length();
        } else {
            spannable.append(mExpandedText);
            drawable = mExpandedDrawable;
            tipsLen = mExpandedText.length();
        }
        // 设置点击事件
        spannable.setSpan(mClickableSpan, spannable.length() - tipsLen,
                spannable.length(), Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
        // 如果提示的图片资源不为空，则使用图片代替提示文本
        if (drawable != null) {
            spannable.setSpan(new ImageSpan(drawable, ImageSpan.ALIGN_BASELINE),
                    spannable.length() - tipsLen, spannable.length(), Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
            spannable.append(" ");
        }
    }

    @Override
    public void setOnClickListener(@Nullable OnClickListener l) {
        // 保存TextView的点击监听事件
        this.mListener = l;
        super.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (!mIsResponseListener) {
            // 如果不响应TextView的点击事件，将属性置为true
            mIsResponseListener = true;
        } else if (mListener != null) {
            // 如果响应TextView的点击事件且监听不为空，则响应点击事件
            mListener.onClick(v);
        }
    }

    /**
     * 提示的点击事件
     */
    private class ExpandedClickableSpan extends ClickableSpan {

        @Override
        public void onClick(View widget) {
            // 是否可点击
            if (mTipsClickable) {
                mIsResponseListener = false;
                mIsExpanded = !mIsExpanded;
                setText(mOriginalText);
            }
        }

        @Override
        public void updateDrawState(TextPaint ds) {
            // 设置提示文本的颜色和是否需要下划线
            ds.setColor(mTipsColor == 0 ? ds.linkColor : mTipsColor);
            ds.setUnderlineText(mTipsUnderline);
        }
    }


    /**
     * 去掉空白字符，这里只去掉了尾部的空白字符
     *
     * @param sequence 需处理的字符
     * @return 处理过的字符
     */
    public static CharSequence trimFrom(CharSequence sequence) {
        int len = sequence.length();
        int first = 0;
        int last;

//        for (first = 0; first < len; first++) {
//            if (!matches(sequence.charAt(first))) {
//                break;
//            }
//        }
        for (last = len - 1; last > first; last--) {
            if (!matches(sequence.charAt(last))) {
                break;
            }
        }

        return sequence.subSequence(first, last + 1);
    }

    private static boolean matches(char c) {
        switch (c) {
            case '\t':
            case '\n':
            case '\013':
            case '\f':
            case '\r':
            case ' ':
            case '\u0085':
            case '\u1680':
            case '\u2028':
            case '\u2029':
            case '\u205f':
            case '\u3000':
                return true;
            case '\u2007':
                return false;
            default:
                return c >= '\u2000' && c <= '\u200a';
        }
    }
}


 <declare-styleable name="CollapsedTextView">
        <attr name="collapsedLines" format="integer" />
        <attr name="expandedText" format="string" />
        <attr name="collapsedText" format="string" />
        <attr name="expandedDrawable" format="reference" />
        <attr name="collapsedDrawable" format="reference" />
        <attr name="tipsGravity">
            <flag name="end" value="0" />
            <flag name="bottom" value="1" />
        </attr>
        <attr name="tipsColor" format="reference|color" />
        <attr name="tipsUnderline" format="boolean" />
        <attr name="tipsClickable" format="boolean" />
    </declare-styleable>