[真实有效]自定义可展开收起TextView，展开收起按钮紧跟文本内容

ExpandTextView.class
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Build;
import android.text.Layout;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.StaticLayout;
import android.text.method.LinkMovementMethod;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;

import com.yimiao100.sale.yimiaomanager.R;


@SuppressLint("AppCompatCustomView")
public class ExpandTextView extends TextView {

    private String originText;// 原始内容文本
    private int initWidth = 0;// TextView可展示宽度
    private int mMaxLines = 3;// TextView最大行数
    private SpannableString SPAN_CLOSE = null;// 收起的文案(颜色处理)
    private SpannableString SPAN_EXPAND = null;// 展开的文案(颜色处理)
    private String TEXT_EXPAND = "  展开描述问题>";
    private String TEXT_CLOSE = "  <收起";

    public ExpandTextView(Context context) {
        super(context);
        initCloseEnd();
    }

    public ExpandTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initCloseEnd();
    }

    public ExpandTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initCloseEnd();
    }

    /**
     * 设置TextView可显示的最大行数
     * @param maxLines 最大行数
     */
    @Override
    public void setMaxLines(int maxLines) {
        this.mMaxLines = maxLines;
        super.setMaxLines(maxLines);
    }

    /**
     * 初始化TextView的可展示宽度
     * @param width
     */
    public void initWidth(int width){
        initWidth = width;
    }

    /**
     * 收起的文案(颜色处理)初始化
     */
    private void initCloseEnd(){
        String content = TEXT_EXPAND;
        SPAN_CLOSE = new SpannableString(content);
        ButtonSpan span = new ButtonSpan(getContext(), new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                ExpandTextView.super.setMaxLines(Integer.MAX_VALUE);
                setExpandText(originText);
            }
        }, R.color.colorAccent);
        SPAN_CLOSE.setSpan(span, 0, content.length(), Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
    }

    /**
     * 展开的文案(颜色处理)初始化
     */
    private void initExpandEnd(){
        String content = TEXT_CLOSE;
        SPAN_EXPAND = new SpannableString(content);
        ButtonSpan span = new ButtonSpan(getContext(), new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                ExpandTextView.super.setMaxLines(mMaxLines);
                setCloseText(originText);
            }
        }, R.color.colorAccent);
        SPAN_EXPAND.setSpan(span, 0, content.length(), Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
    }

    public void setCloseText(CharSequence text) {

        if(SPAN_CLOSE == null){
            initCloseEnd();
        }
        boolean appendShowAll = false;// true 不需要展开收起功能， false 需要展开收起功能
        originText = text.toString();

        // SDK >= 16 可以直接从xml属性获取最大行数
        int maxLines = 0;
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
            maxLines = getMaxLines();
        } else{
            maxLines = mMaxLines;
        }
        String workingText = new StringBuilder(originText).toString();
        if (maxLines != -1) {
            Layout layout = createWorkingLayout(workingText);
            if (layout.getLineCount() > maxLines) {
                //获取一行显示字符个数，然后截取字符串数
                workingText = originText.substring(0, layout.getLineEnd(maxLines - 1)).trim();// 收起状态原始文本截取展示的部分
                String showText = originText.substring(0, layout.getLineEnd(maxLines - 1)).trim() + "..." + SPAN_CLOSE;
                Layout layout2 = createWorkingLayout(showText);
                // 对workingText进行-1截取，直到展示行数==最大行数，并且添加 SPAN_CLOSE 后刚好占满最后一行
                while (layout2.getLineCount() > maxLines) {
                    int lastSpace = workingText.length()-1;
                    if (lastSpace == -1) {
                        break;
                    }
                    workingText = workingText.substring(0, lastSpace);
                    layout2 = createWorkingLayout(workingText + "..." + SPAN_CLOSE);
                }
                appendShowAll = true;
                workingText = workingText + "...";
            }
        }

        setText(workingText);
        if (appendShowAll) {
            // 必须使用append，不能在上面使用+连接，否则spannable会无效
            append(SPAN_CLOSE);
            setMovementMethod(LinkMovementMethod.getInstance());
        }
    }

    public void setExpandText(String text) {
        if(SPAN_EXPAND == null){
            initExpandEnd();
        }
        Layout layout1 = createWorkingLayout(text);
        Layout layout2 = createWorkingLayout(text + TEXT_CLOSE);
        // 展示全部原始内容时 如果 TEXT_CLOSE 需要换行才能显示完整，则直接将TEXT_CLOSE展示在下一行
        if(layout2.getLineCount() > layout1.getLineCount()){
            setText(originText + "\n");
        }else{
            setText(originText);
        }
        append(SPAN_EXPAND);
        setMovementMethod(LinkMovementMethod.getInstance());
    }

    //返回textview的显示区域的layout，该textview的layout并不会显示出来，只是用其宽度来比较要显示的文字是否过长
    private Layout createWorkingLayout(String workingText) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            return new StaticLayout(workingText, getPaint(), initWidth - getPaddingLeft() - getPaddingRight(),
                    Layout.Alignment.ALIGN_NORMAL, getLineSpacingMultiplier(), getLineSpacingExtra(), false);
        } else{
            return new StaticLayout(workingText, getPaint(), initWidth - getPaddingLeft() - getPaddingRight(),
                    Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
        }
    }

}

ButtonSpan.class

import android.content.Context;
import android.text.TextPaint;
import android.text.style.ClickableSpan;
import android.view.View;

import com.yimiao100.sale.yimiaomanager.R;

/**
 * Created by Michel on 2018/7/24.
 */
public class ButtonSpan extends ClickableSpan {
    View.OnClickListener onClickListener;
    private Context context;
    private int colorId;

    public ButtonSpan(Context context, View.OnClickListener onClickListener) {
        this(context, onClickListener, R.color.colorAccent);
    }

    public ButtonSpan(Context context, View.OnClickListener onClickListener, int colorId){
        this.onClickListener = onClickListener;
        this.context = context;
        this.colorId = colorId;
    }


    public void updateDrawState(TextPaint ds) {
        ds.setColor(context.getResources().getColor(colorId));
        ds.setUnderlineText(false);
    }


    public void onClick(View widget) {
        if (onClickListener != null) {
            onClickListener.onClick(widget);
        }
    }

}

ScreenUtils class

import android.content.Context;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.WindowManager;

/**
 * Created by chenjie on 18-7-26.
 */

public class ScreenUtils {
    private ScreenUtils()
    {
        /* cannot be instantiated */
        throw new UnsupportedOperationException("cannot be instantiated");
    }
    /**
     * 获得屏幕宽度
     *
     * @param context
     * @return
     */
    public static int getScreenWidth(Context context)
    {
        WindowManager wm = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics outMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(outMetrics);
        return outMetrics.widthPixels;
    }

    /**
     * dp转px
     *
     * @param context
     * @param dpVal
     * @return
     */
    public static int dp2px(Context context, float dpVal) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
                dpVal, context.getResources().getDisplayMetrics());
    }
}

使用

• list = new ArrayList<String>();
  for (int i = 1; i < 10; i++)
  {
      list.add("aaaaaaqqqqqqqqqqqqqqqqqqqqqqqqqqqaaaaeeeeeeeeeeeeeeeeeeeeeeeeeaaaa" +
              "aaaaaaaqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqaaaaaa，" +
              "aaaaaqqqqqqqqqqqqqqqqqqqqaaaaaaaaaaaaaa" +
              "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" +
              "aaaaaaaaaaaaaaaaaaaaaaaaa");
  
  }

  int whidth = ScreenUtils.getScreenWidth(getActivity()) - ScreenUtils.dp2px(getActivity(),16*2);
     holder.text_expand.initWidth(whidth);
     holder.text_expand.setMaxLines(3);
     holder.text_expand.setCloseText(list.get(position));