<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
  <TextView
    android:id="@+id/content"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="16sp"
    android:maxLines="3"
    android:ellipsize="end"/>
  <TextView
    android:id="@+id/hide_show"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/btn_showmore"
    android:textColor="@color/colorBlue"
    android:textSize="16sp"
    android:text="顯示更多"
    android:padding="0dp"
    />
</LinearLayout>

//新建java類繼承自LinearLayout
public class ShowMoreTextView extends LinearLayout {
//  用來標(biāo)記是否為展開狀態(tài)
  private int hideOrShow = 0;
  private TextView textView;
  private TextView button;

  public ShowMoreTextView(Context context) {
    super(context);
  }

  public ShowMoreTextView(Context context, AttributeSet attrs) {
    super(context, attrs);
//    實(shí)例化layoutInflater對(duì)象，獲取到布局填充服務(wù)
    LayoutInflater layoutInflater = (LayoutInflater)context.
        getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//    填充自定義的布局xml文件
    layoutInflater.inflate(R.layout.showmore,this);
    textView = (TextView)findViewById(R.id.content);
    button=(TextView) findViewById(R.id.hide_show);
    button.setText("顯示更多");
//    隱藏或顯示
    hideOrShow();
  }
//  創(chuàng)建setContent方法為TextView填充內(nèi)容
  public void setContent(String content) {
    textView.setText(content);
  }

  public void hideOrShow() {
    button.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
      //由hideOrShow的值確定按鈕和textview的狀態(tài)
        if (hideOrShow == 0) {
          button.setText("收起");
          textView.setMaxLines(100);
          hideOrShow = 2;
        }else if(hideOrShow==2){
          button.setText("顯示更多");
          textView.setMaxLines(3);
          hideOrShow = 1;
        }else if(hideOrShow==1){
          button.setText("收起");
          textView.setMaxLines(100);
          hideOrShow=2;
        }
      }
    });
  }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:paddingBottom="@dimen/activity_vertical_margin"
  android:paddingLeft="@dimen/activity_horizontal_margin"
  android:paddingRight="@dimen/activity_horizontal_margin"
  android:paddingTop="@dimen/activity_vertical_margin"
  tools:context="com.commy.activity.TestActivity">

  <com.yunfeng.laojiahenan.view.ShowMoreTextView
    android:id="@+id/showmore"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"/>
</RelativeLayout>

public class TestActivity extends AppCompatActivity {
  private ShowMoreTextView showMoreTextView;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_test);
    showMoreTextView=(ShowMoreTextView)findViewById(R.id.showmore);
    showMoreTextView.setContent("
      There is so much life
      I've left to live
      And this fire's burning still
      When I watch you look at me 
      I think I could find a way
      To stand for every dream
      And forsake this solid ground
      And give up this fear within
      Of what would happen if they end you
      I'm in love with you
    ");
  }
}