Android自定义TextView仿微信朋友圈文字展开全文功能

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//新建java类继承自LinearLayout
public class ShowMoreTextView extends LinearLayout {
//  用来标记是否为展开状态
  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);
//    实例化layoutInflater对象，获取到布局填充服务
    LayoutInflater layoutInflater = (LayoutInflater)context.
        getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//    填充自定义的布局xml文件
    layoutInflater.inflate(R.layout.showmore,this);
    textView = (TextView)findViewById(R.id.content);
    button=(TextView) findViewById(R.id.hide_show);
    button.setText("显示更多");
//    隐藏或显示
    hideOrShow();
  }
//  创建setContent方法为TextView填充内容
  public void setContent(String content) {
    textView.setText(content);
  }

  public void hideOrShow() {
    button.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
      //由hideOrShow的值确定按钮和textview的状态
        if (hideOrShow == 0) {
          button.setText("收起");
          textView.setMaxLines(100);
          hideOrShow = 2;
        }else if(hideOrShow==2){
          button.setText("显示更多");
          textView.setMaxLines(3);
          hideOrShow = 1;
        }else if(hideOrShow==1){
          button.setText("收起");
          textView.setMaxLines(100);
          hideOrShow=2;
        }
      }
    });
  }
}

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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
    ");
  }
}