自定義TextView仿微信朋友圈文字資訊，展開全文功能
程式碼及註釋如下：
首先寫一個xml檔案 showmore.xml：

<?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 {
//    用來標記是否為展開狀態
    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);
//        例項化layoutInflater物件，獲取到佈局填充服務
        LayoutInflater layoutInflater = (LayoutInflater)context.
                getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//        填充自定義的佈局xml檔案
        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();
    }
//    建立setContent方法為TextView填充內容
    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
                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;
                }
            }
        });
    }
}

接下來就可以引用了，與普通的控制元件一樣 activity_test.xml：

<?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>

測試類：

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
        ");
    }
}