Android 之TextView文本折叠查看显示更多效果

1. 自定义CollapsibleTextView继承LinearLayout

 /**
 *          
 * Created by Administrator on 2016/3/22.
 */
 
public class CollapsibleTextView extends LinearLayout implements OnClickListener {

    /** default text show max lines */
    private static final int DEFAULT_MAX_LINE_COUNT = 2;

    private static final int COLLAPSIBLE_STATE_NONE = 0;
    private static final int COLLAPSIBLE_STATE_SHRINKUP = 1;
    private static final int COLLAPSIBLE_STATE_SPREAD = 2;

    private TextView desc;
    private TextView descOp;

    private String shrinkup;
    private String spread;
    private int mState;
    private boolean flag;

    public CollapsibleTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
 //        两种定义形式
//        shrinkup = context.getString(R.string.desc_shrinkup);
//        spread = context.getString(R.string.desc_spread);
        shrinkup="收起";
        spread="查看更多";
        View view = inflate(context, R.layout.collapsible_textview, this);
        view.setPadding(0, -1, 0, 0);
        desc = (TextView) view.findViewById(R.id.desc_tv);
        descOp = (TextView) view.findViewById(R.id.desc_op_tv);
        descOp.setOnClickListener(this);
    }

    public CollapsibleTextView(Context context) {
        this(context, null);
    }
/**
 1. 
 2. 对外提供暴漏的方法，为文本提供数据
 3. @param charSequence  文本内容是什么
 4. @param bufferType
 */
    public final void setDesc(CharSequence charSequence, BufferType bufferType) {
        desc.setText(charSequence, bufferType);
        mState = COLLAPSIBLE_STATE_SPREAD;
        requestLayout();
    }

    @Override
    public void onClick(View v) {
        flag = false;
        requestLayout();
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);
        if (!flag) {
            flag = true;
            if (desc.getLineCount() <= DEFAULT_MAX_LINE_COUNT) {
                mState = COLLAPSIBLE_STATE_NONE;
                descOp.setVisibility(View.GONE);
                desc.setMaxLines(DEFAULT_MAX_LINE_COUNT + 1);
            } else {
                post(new InnerRunnable());
            }
        }
    }

    class InnerRunnable implements Runnable {
        @Override
        public void run() {
            if (mState == COLLAPSIBLE_STATE_SPREAD) {
                desc.setMaxLines(DEFAULT_MAX_LINE_COUNT);
                descOp.setVisibility(View.VISIBLE);
                descOp.setText(spread);
                mState = COLLAPSIBLE_STATE_SHRINKUP;
            } else if (mState == COLLAPSIBLE_STATE_SHRINKUP) {
                desc.setMaxLines(Integer.MAX_VALUE);
                descOp.setVisibility(View.VISIBLE);
                descOp.setText(shrinkup);
                mState = COLLAPSIBLE_STATE_SPREAD;
            }
        }
    }
}

2. collapsible_textview.xml定义

<?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/desc_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="4.0dip"
        android:gravity="center_vertical"
        android:textColor="#ff000000"
        android:textSize="14.0dip" />
    
<!--可以灵活的将收藏的按钮至右 至左 居中  -->
    <TextView
        android:id="@+id/desc_op_tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="4.0dip"
        android:gravity="right"
        
        android:singleLine="true"
        android:textColor="#ff576b95"
        android:textSize="14.0dip"
        android:visibility="gone" />

</LinearLayout>

3.使用：

public class Main extends Activity {

    String s = "但发斯蒂芬的佛教啊哦啊二等奖发了恐惧似懂非懂，爱递交奇怪阿尔发票奥支付到上世纪的阿斯顿发送到撒旦法大的事发的爱的色放的阿斯顿发阿斯顿发阿萨德发的多发点";

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

        CollapsibleTextView tv = (CollapsibleTextView) findViewById(R.id.desc_collapse_tv);
        tv.setDesc(s, BufferType.NORMAL);
        
        
        
    }

}

效果图：