点击可展开的TextView

自定义TextView

package com.sun.mytext;

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;

/**
 * @author Sigal
 * on 2018/12/18
 * note: 可展开的TextView
 */
@SuppressLint("AppCompatCustomView")
public class ExpandTextView extends TextView {
    // 原始内容文本
    private String originText;
    // TextView可展示宽度
    private int initWidth = 0;
    // TextView最大行数
    private int mMaxLines = 3;
    // 收起的文案(颜色处理)
    private SpannableString SPAN_CLOSE = null;
    // 展开的文案(颜色处理)
    private SpannableString SPAN_EXPAND = null;
    private String TEXT_EXPAND = "  查看更多>";
    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);
        }
    }
}

自定义ClickableSpan

package com.sun.mytext;

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

/**
 * @author Sigal
 * on 2018/12/18
 * note:
 */
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.textColor);
    }

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

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

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

}

PxUtils 和 ScreenUtils

package com.sun.mytext;

import android.content.Context;

/**
 * @author Sigal
 * on 2018/12/18
 * note: px与dp、sp的转换
 */
public class PxUtils {
    /**
     * 将px转换为与之相等的dp
     */
    public static int px2dp(Context context, float pxValue) {
        final float scale =  context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }

    /**
     * 将dp转换为与之相等的px
     */
    public static int dp2px(Context context, float dipValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dipValue * scale + 0.5f);
    }

    /**
     * 将px转换为sp
     */
    public static int px2sp(Context context, float pxValue) {
        final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
        return (int) (pxValue / fontScale + 0.5f);
    }

    /**
     * 将sp转换为px
     */
    public static int sp2px(Context context, float spValue) {
        final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
        return (int) (spValue * fontScale + 0.5f);
    }

}

package com.sun.mytext;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.WindowManager;

/**
 * @author Sigal
 * on 2018/12/18
 * note:
 */
public class ScreenUtils {
    private ScreenUtils()
    {
        /* cannot be instantiated */
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /**
     * 获得屏幕高度
     * @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;
    }

    /**
     * 获得屏幕宽度
     * @param context
     * @return
     */
    public static int getScreenHeight(Context context)
    {
        WindowManager wm = (WindowManager) context
                .getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics outMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(outMetrics);
        return outMetrics.heightPixels;
    }

    /**
     * 获得状态栏的高度
     * @param context
     * @return
     */
    public static int getStatusHeight(Context context)
    {

        int statusHeight = -1;
        try
        {
            Class<?> clazz = Class.forName("com.android.internal.R$dimen");
            Object object = clazz.newInstance();
            int height = Integer.parseInt(clazz.getField("status_bar_height")
                    .get(object).toString());
            statusHeight = context.getResources().getDimensionPixelSize(height);
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return statusHeight;
    }

    /**
     * 获取当前屏幕截图，包含状态栏
     * @param activity
     * @return
     */
    public static Bitmap snapShotWithStatusBar(Activity activity)
    {
        View view = activity.getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();
        Bitmap bmp = view.getDrawingCache();
        int width = getScreenWidth(activity);
        int height = getScreenHeight(activity);
        Bitmap bp = null;
        bp = Bitmap.createBitmap(bmp, 0, 0, width, height);
        view.destroyDrawingCache();
        return bp;

    }

    /**
     * 获取当前屏幕截图，不包含状态栏
     * @param activity
     * @return
     */
    public static Bitmap snapShotWithoutStatusBar(Activity activity) {
        View view = activity.getWindow().getDecorView();
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache();
        Bitmap bmp = view.getDrawingCache();
        Rect frame = new Rect();
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
        int statusBarHeight = frame.top;

        int width = getScreenWidth(activity);
        int height = getScreenHeight(activity);
        Bitmap bp = null;
        bp = Bitmap.createBitmap(bmp, 0, statusBarHeight, width, height
                - statusBarHeight);
        view.destroyDrawingCache();
        return bp;
    }
}

代码引用

package com.sun.mytext;

import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
/**
 * @author Sigal
 * on 2018/12/18
 * note:
 */
public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 设置TextView可展示的宽度 ( 父控件宽度 - 左右margin - 左右padding）
        int whidth = ScreenUtils.getScreenWidth(this) - PxUtils.dp2px(this, 16 * 2);
        ExpandTextView mContentExpandTextView = findViewById(R.id.etv);
        mContentExpandTextView.initWidth(whidth);
        // 设置最大行数(如果SDK >= 16 也可以直接在xml里设置)
        mContentExpandTextView.setMaxLines(3);
        String content = "披绣闼，俯雕甍，山原旷其盈视，川泽纡其骇瞩。闾阎扑地，钟鸣鼎食之家；" +
                "舸舰弥津，青雀黄龙之舳。云销雨霁，彩彻区明。落霞与孤鹜齐飞，秋水共长天一色。渔舟唱晚，响穷彭蠡之滨；雁阵惊寒，声断衡阳之浦。\n" +
                "\n" +
                "遥襟甫畅，逸兴遄飞。爽籁发而清风生，纤歌凝而白云遏。睢园绿竹，气凌彭泽之樽；" +
                "邺水朱华，光照临川之笔。四美具，二难并。穷睇眄于中天，极娱游于暇日。天高地迥，" +
                "觉宇宙之无穷；兴尽悲来，识盈虚之有数。望长安于日下，目吴会于云间。地势极而南溟深，天柱高而北辰远。关山难越，" +
                "谁悲失路之人？萍水相逢，尽是他乡之客。怀帝阍而不见，奉宣室以何年？\n" +
                "\n" +
                "嗟乎！时运不齐，命途多舛。冯唐易老，李广难封。屈贾谊于长沙，非无圣主；窜梁鸿于海曲，岂乏明时？所赖君子见机，达人知命。" +
                "老当益壮，宁移白首之心？穷且益坚，不坠青云之志。酌贪泉而觉爽，处涸辙以犹欢。北海虽赊，扶摇可接；东隅已逝，桑榆非晚。" +
                "孟尝高洁，空余报国之情；阮籍猖狂，岂效穷途之哭！";
        mContentExpandTextView.setCloseText(content);
    }
}

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.sun.mytext.ExpandTextView
        android:id="@+id/etv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

 

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