轉載請註明來源！

一般列表裡文字太多的一個摺疊效果的空間，效果圖如下。

當文字超過設定的行數後就摺疊，小於設定行數不顯示展開按鈕。下面上程式碼。
先看佈局檔案：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background
 
="@color/color_white" >
    <TextView
        android:id="@+id/desc_tv"
        style="@style/font2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_vertical" />
    <TextView
        android:id="@+id/desc_op_tv"
        android:layout_width
 
="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/desc_tv"
        android:gravity="center_vertical"
        android:singleLine="true"
        android:text="@string/quan_wen"
        android:textColor="#5f897b"
        android:textSize="16sp"
        android:visibility
 
="gone" />
</RelativeLayout>

很簡單，上面的TextView顯示主要的文字內容，下面的就是摺疊的時候點選的。

下面是自定義。

package xxx;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.TextView.BufferType;
import xxx.R;
/**
 * 檢視全文控制元件
 */
public class CollapsibleTextView extends LinearLayout implements View.OnClickListener {
    private static final int COLLAPSIBLE_STATE_NONE = 0;// 不顯示
    private static final int COLLAPSIBLE_STATE_SHRINKUP = 1;// 顯示收起
    private static final int COLLAPSIBLE_STATE_SPREAD = 2;// 顯示全文
    private int mState = COLLAPSIBLE_STATE_SPREAD;
    private static final String COLLAPSIBLE_STATE_SHRINKUP_TEXT = "收起";
    private static final String COLLAPSIBLE_STATE_SPREAD_TEXT = "全文";
    private TextView mText;
    /**
     * @return Returns the mText.
     */
    public TextView getmText() {
        return mText;
    }
    public int getmState() {
        return mState;
    }
    public void setmState(int mState) {
        this.mState = mState;
    }
    private TextView mTextTip;
    private changeState changeStateCallBack;
    private boolean isNeedLayout;
    private int maxLineCount = 8;
    private final Handler handler = new Handler() {
        @Override
        public void dispatchMessage(Message msg) {
            if (mText.getLineCount() <= maxLineCount) {
                // 行數不足不做處理
                mState = COLLAPSIBLE_STATE_NONE;
                mText.setMaxLines(Integer.MAX_VALUE);
                mTextTip.setVisibility(View.GONE);
            }
            else {
                switch (mState) {
                case COLLAPSIBLE_STATE_SPREAD:
                    // 全文狀態
                    mText.setMaxLines(maxLineCount);
                    mTextTip.setVisibility(View.VISIBLE);
                    mTextTip.setText(COLLAPSIBLE_STATE_SPREAD_TEXT);
                    break;
                case COLLAPSIBLE_STATE_SHRINKUP:
                    // 收起狀態
                    mText.setMaxLines(Integer.MAX_VALUE);
                    mTextTip.setVisibility(View.VISIBLE);
                    mTextTip.setText(COLLAPSIBLE_STATE_SHRINKUP_TEXT);
                    break;
                default:
                    // 除非發生不可知狀態，一般不會執行到這個
                    mState = COLLAPSIBLE_STATE_NONE;
                    mText.setMaxLines(Integer.MAX_VALUE);
                    mTextTip.setVisibility(View.GONE);
                    break;
                }
            }
        }
    };
    public CollapsibleTextView(Context context) {
        this(context, null);
        initView();
    }
    public CollapsibleTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView();
    }
    @SuppressLint("NewApi")
    public CollapsibleTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initView();
    }
    private void initView() {
        View view = inflate(getContext(), R.layout.collapsible_textview, this);
        view.setPadding(0, -1, 0, 0);
        mText = (TextView) view.findViewById(R.id.desc_tv);
        mTextTip = (TextView) view.findViewById(R.id.desc_op_tv);
        mTextTip.setOnClickListener(this);
    }
    /**
     * 設定文字
     * 
     * @param charSequence
     * @param bufferType
     */
    public final void setText(CharSequence charSequence, BufferType bufferType) {
        isNeedLayout = true;
        mState = COLLAPSIBLE_STATE_SPREAD;
        mText.setText(charSequence, bufferType);
    }
    /**
     * 設定文字
     * 
     * @param charSequence
     */
    public final void setText(CharSequence charSequence) {
        isNeedLayout = true;
        mText.setText(charSequence);
    }
    @Override
    public void onClick(View v) {
        isNeedLayout = true;
        if (mState == COLLAPSIBLE_STATE_SPREAD) {
            // 如果是全文狀態，就改成收起狀態
            mState = COLLAPSIBLE_STATE_SHRINKUP;
            requestLayout();
        }
        else if (mState == COLLAPSIBLE_STATE_SHRINKUP) {
            // 如果是收起狀態，就改成全文狀態
            mState = COLLAPSIBLE_STATE_SPREAD;
            requestLayout();
        }
        if (null != changeStateCallBack) {
            changeStateCallBack.changeFlag(v);
        }
    }
    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        super.onLayout(changed, l, t, r, b);
        if (isNeedLayout) {
            isNeedLayout = false;
            handler.sendMessage(Message.obtain());
        }
    }
    public int getMaxLineCount() {
        return maxLineCount;
    }
    public void setMaxLineCount(int maxLineCount) {
        this.maxLineCount = maxLineCount;
    }
    public changeState getChangeStateCallBack() {
        return changeStateCallBack;
    }
    public void setChangeStateCallBack(changeState changeStateCallBack) {
        this.changeStateCallBack = changeStateCallBack;
    }
    public interface changeState {
        public void changeFlag(View v);
    }
}

點選展開後重新繪製根據狀態值觸發。

轉載請註明來源！