文字末尾加图片按钮，点击按钮打开折叠文字，设置文字显示指定行数TextApp,textview结尾图片折叠文字
文字末尾加图片按钮，点击按钮打开折叠文字，设置文字显示指定行数TextApp,textview结尾图片折叠文字， 实现效果 把长文字 折叠成1行或者指定行显示，末尾加... + 图片，点击图片展开全部文字显示或者折叠成1行（或者指定行）显示。
上代码：
1、MainActivity.java
package com.android.textapp;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.TextPaint;
import android.text.TextUtils;
import android.text.method.LinkMovementMethod;
import android.text.style.ClickableSpan;
import android.text.style.ImageSpan;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.View;
import android.view.ViewTreeObserver;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
public class MainActivity extends AppCompatActivity {
private String resourceStr;
private String shortStr;
private TextView textView;
// 默认显示2行
private int defaultLine = 2;
private boolean expored = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
intView();
}
private void intView() {
textView = findViewById(R.id.textView);
textView.getViewTreeObserver().addOnPreDrawListener(new MyOnPreDrawListener());
resourceStr = "国要要顺在要个有爱是你我，，可. 楷经？《要，》国要要顺在要个有爱是你我，，可. 楷经？《==要，》国要要顺在要个有爱是你我，，可. 楷经？《要，》国要要顺在要个有爱是你我，，可. 楷经？【《要，》国要要顺在要个有爱是你我，，可. 楷经？《要，》国要要顺在要个有爱是你我，，可. 楷经？】】《要，》国要要顺在要个有爱是你我，，可. 楷经？《要，》国要要顺在要个有爱是你我，，可. 、、楷经？《要，》国要要顺在要个有爱是你我，，可. 楷经？《要，》国要要顺在要个有爱是你我，，可.，楷经？《要，》国要要顺在要个有爱是你我，，可. 楷经？《要，》国要要顺在要个有爱是你我，，可. 楷经？《要，》" ;
textView.setText(resourceStr);
int num = getLineMaxNumber(getBaseContext(), textView);
if (resourceStr.length() > num * defaultLine) {
shortStr = subStringRows(getBaseContext(), textView, resourceStr , defaultLine);
} else {
shortStr = resourceStr;
}
}
public class MyOnPreDrawListener implements ViewTreeObserver.OnPreDrawListener {
@Override
public boolean onPreDraw() {
textView.getViewTreeObserver().removeOnPreDrawListener(this);
int line = textView.getLineCount();
Log.e("lines" , "lines= " + line);
// 多行文字折叠处理
if (line <= defaultLine) {
textView.setText(resourceStr);
} else {
setIcon(expored, new MyClickableSpan());
}
return true;
}
};
public class MyClickableSpan extends ClickableSpan {
@Override
public void onClick(@NonNull View widget) {
expored = !expored;
Log.e("MainActivity","textView图片点击------ widget.isSelected()= " + widget.isSelected() + " ,expored= " + expored);
setIcon(expored, this);
}
}
private void setIcon(boolean expored, MyClickableSpan myClickableSpan) {
setIcon(expored, myClickableSpan, true);
}
private void setIcon(boolean expored, ClickableSpan clickableSpan, boolean hasImage) {
int tvIconResId = 0;
if (hasImage) {
tvIconResId = expored ? R.mipmap.icon_arror_fold : R.mipmap.icon_arror_expand;
}
String inputStr;
if (expored) {
inputStr = resourceStr;
} else {
inputStr = shortStr;
}
textViewDrawableIcon(getBaseContext(), textView, inputStr.trim(), tvIconResId, clickableSpan);
}
/**
* 在textview末尾增加图片，并增加图片的点击事件监听
*/
private void textViewDrawableIcon(Context context, TextView tv, String input, int picResId,
ClickableSpan clickableSpan) {
if (context == null || tv == null) {
return;
}
SpannableString ss = new SpannableString(input + " ");
int len = ss.length();
//图片
Drawable d = ContextCompat.getDrawable(context, picResId);
d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
//构建ImageSpan
ImageSpan span = new ImageSpan(d, ImageSpan.ALIGN_BASELINE);
ss.setSpan(span, len - 1, len, Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
if (clickableSpan != null) {
ss.setSpan(clickableSpan, len - 1, len, Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
}
tv.setText(ss);
//需要设置这个才能点击
tv.setMovementMethod(LinkMovementMethod.getInstance());
//去掉高亮，不然点击时候背景会变高亮
tv.setHighlightColor(context.getResources().getColor(android.R.color.transparent));
}
/**
* 获取textview一行显示的文字数
*/
private int getLineMaxNumber(Context context, TextView textView) {
DisplayMetrics dm = context.getResources().getDisplayMetrics();
int widthScreen = dm.widthPixels;
int width = (widthScreen - dip2px( 28));
int num = Math.round(width / textView.getTextSize());
return num;
}
private int dip2px(int dxValue) {
float mScale = getResources().getDisplayMetrics().density;
return (int) (dxValue * mScale + 0.5f);
}
/**
* 截取textView显示的文字的指定行数，例如：截取前3行文字。
* @param line 要截取的行数
*/
private String subStringRows(Context context, TextView textView, String sourceStr, int line) {
if (context == null) {
return sourceStr;
}
if (TextUtils.isEmpty(sourceStr)) {
return "";
}
DisplayMetrics dm = context.getResources().getDisplayMetrics();
int screenwidth = dm.widthPixels;
// 28 是textview 距离屏幕两侧间距
int width = (screenwidth - dip2px( 28));
TextPaint paint = textView.getPaint();
int wordwidth = (int)paint.measureText("a",0,1);
int num = (int) (width/wordwidth);
sourceStr = sourceStr.substring(0, (num * line)/2-3) + "...";
return replaceAllSpecialCharacters(sourceStr);
}
private String replaceAllSpecialCharacters(String sourceStr) {
if (TextUtils.isEmpty(sourceStr)) {
return "";
}
sourceStr = sourceStr.replace("\\s","")
.replace("\n","")
.replace("\t","")
.replace("\r","");
return sourceStr;
}
}2、布局文件 activity_main2.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="14dp"
android:layout_marginTop="140dp"
android:layout_marginEnd="14dp"
android:text=""
android:textColor="#000000"
android:textSize="14sp" />
</LinearLayout>图片资源： 
源码下载地址；
（文字末尾加图片按钮，点击按钮打开折叠文字，设置文字显示指定行数TextApp-Android文档类资源-CSDN下载）