文本展示多行隐藏及显示全部

还是简单干脆 废话不多说直接上代码

       package com.smy.textviewdemo;

        import android.annotation.SuppressLint;
        import android.content.Context;
        import android.graphics.Color;
        import android.text.Layout;
        import android.text.SpannableString;
        import android.text.Spanned;
        import android.text.StaticLayout;
        import android.text.TextPaint;
        import android.text.style.ForegroundColorSpan;
        import android.view.View;
        import android.widget.TextView;

        public class MyMoreText implements View.OnClickListener {
            private SpannableString eclipseString;    //收起的文字
            private SpannableString notEclipseString; //展开的文字
            private TextView textView;
 
    private static class MoreTextHolder {
        @SuppressLint("StaticFieldLeak")
        private static final MyMoreText INSTANCE = new MyMoreText();
    }
 
    public static MyMoreText getInstance() {
        return MyMoreText.MoreTextHolder.INSTANCE;
    }
 
    public void getLastIndexForLimit(TextView tv, int maxLine, String content) {
        this.textView = tv;
        //获取TextView的画笔对象
        TextPaint paint = textView.getPaint();
        //每行文本的布局宽度
        int width = MyApplication.getInstance().getResources().getDisplayMetrics().widthPixels - dip2px(MyApplication.getInstance(), 40);
        //实例化StaticLayout 传入相应参数
        StaticLayout staticLayout = new StaticLayout(content, paint, width, Layout.Alignment.ALIGN_NORMAL, 1, 0, false);
        //判断content是行数是否超过最大限制行数3行
        if (staticLayout.getLineCount() > maxLine) {
            //定义展开后的文本内容
            String string1 = content + "    收起";
            notEclipseString = new SpannableString(string1);
            //给收起两个字设成蓝色
            notEclipseString.setSpan(new ForegroundColorSpan(Color.parseColor("#0079e2")), string1.length() - 2, string1.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            //获取到第三行最后一个文字的下标
            int index = staticLayout.getLineStart(maxLine) - 1;
            //定义收起后的文本内容
            String substring = content.substring(0, index - 4) + "..." + "查看全部";
            eclipseString = new SpannableString(substring);
            //给查看全部设成蓝色
            eclipseString.setSpan(new ForegroundColorSpan(Color.parseColor("#0079e2")), substring.length() - 4, substring.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            //设置收起后的文本内容
            tv.setText(eclipseString);
            tv.setOnClickListener(this);
            //将textView设成选中状态 true用来表示文本未展示完全的状态,false表示完全展示状态，用于点击时的判断
            tv.setSelected(true);
        } else {
            //没有超过 直接设置文本
            tv.setText(content);
            tv.setOnClickListener(null);
        }
    }
 
    /**
     * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
     */
    private static int dip2px(Context mContext, float dpValue) {
        final float scale = mContext.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
 
    @Override
    public void onClick(View view) {
        if (view.isSelected()) {
            //如果是收起的状态
            textView.setText(notEclipseString);
            textView.setSelected(false);
        } else {
            //如果是展开的状态
            textView.setText(eclipseString);
            textView.setSelected(true);
        }
    }
    }

其次要自定义一个application
      package com.smy.textviewdemo;

      import android.app.Application;
      import android.content.Context;

    public class MyApplication extends Application {
        private static MyApplication instance;
 
    public static MyApplication getInstance() {
        return instance;
    }
 
    public static Context mAppContext = null;
 
    @Override
    public void onCreate() {
        super.onCreate();
        instance = this;
    }
    }

mainactivity 代码

        package com.smy.textviewdemo;

        import android.os.Bundle;
        import android.support.v7.app.AppCompatActivity;
        import android.widget.TextView;

        public class MainActivity extends AppCompatActivity {

    /**
     * Hello World!
     */
    private TextView mTv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }

    private void initView() {
        mTv = (TextView) findViewById(R.id.tv);
        //目标textView，显示内容的行数，textView具体内容
        MyMoreText.getInstance().getLastIndexForLimit(mTv, 2, "123122222222222222222222222222222333333333333333333333333333333333333333333333333333333333333333333333333333333333333qwewaeahduiasdhdddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddduwihdihdsjkfhldsafjhasdifajkfhlkasdhfauiewfl");

          }
      }

xml代码

        <?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"
          android:gravity="top"
          tools:context=".MainActivity">
        
    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:gravity="center"
        android:text="@string/app_name"/>

      </LinearLayout>

直接贴代码就能使用 拿走