Android 應用中TextView垂直滾動

項目中歡迎詞多的時候需要實現上下滾動，了解到在android中TextView可以輕松實現橫向跑馬燈效果，但是對垂直滾動沒有直接的支持方法，于是百度上谷歌，谷歌上百度，最終還是沒有發現一個拿來即用的demo，呵呵，于是自己研究了下，寫了一個可以實現TextView垂直滾動的 demo，由于項目需要，在這里我使用的是AbsoluteLayout布局，左右鍵切換時更改滾動內容，希望此demo能給有同樣需求的童鞋們帶來幫助！

---寫在前面

textscroll.xml配置：

    <?xml version="1.0" encoding="utf-8"?>  
    <AbsoluteLayout 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/tScroll"  
            android:layout_width="fill_parent"  
            android:layout_height="wrap_content"  
            android:maxLines="5"  
            android:scrollbars="none"  
            android:singleLine="false"  
            android:textColor="#FF0000" >  
        </TextView>  

    </AbsoluteLayout>  

    package sue.test;  

    import java.util.ArrayList;  
    import java.util.List;  

    import com.amttgroup.element.Container;  
    import com.amttgroup.element.RootLayout;  
    import com.amttgroup.element.Text;  
    import com.amttgroup.utils.G;  

    import android.app.Activity;  
    import android.graphics.Color;  
    import android.os.Bundle;  
    import android.os.Handler;  
    import android.util.Log;  
    import android.view.Gravity;  
    import android.view.KeyEvent;  
    import android.widget.AbsoluteLayout;  
    import android.widget.TextView;  

    public class TextScrollActivity extends Activity {  
        TextView tv;  
        String L = "TextScrollActivity";  
        List<String> welcomeWords = new ArrayList<String>();  
        int curIndex = 0;  

        @Override  
        protected void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  

            welcomeWords  
                    .add("        您的下榻使我們倍感榮幸。我謹代表北京飯店全體員工向您表示誠摯的歡迎。始建于1900年的北京飯店是一座歷史悠久的豪華飯店。擁有豪華典雅的客房；口味獨特的佳肴；會議會展設施及娛樂健身設施。我們將竭誠為您提供滿意而舒適的服務。希望您在北京飯店下榻愉快。\n 您的下榻使我們倍感榮幸。我謹代表北京飯店全體員工向您表示誠摯的歡迎。始建于1900年的北京飯店是一座歷史悠久的豪華飯店。擁有豪華典雅的客房；口味獨特的佳肴；會議會展設施及娛樂健身設施。我們將竭誠為您提供滿意而舒適的服務。希望您在北京飯店下榻愉快。");  
            welcomeWords  
                    .add("  It is an honor for you to stay at the Beijing Hotel. On behalf of the staff at the Beijing Hotel, I sincerely welcome you.Built in 1900, Beijing Hotel is a luxury hotel with a long history. We have elegant guestrooms, exquisite cuisine, convenient facilities and entertainment facilities. It is our pleasure to offer you the best services.Have a nice stay!");  

            setContentView(R.layout.textscroll);  

            tv = (TextView) findViewById(R.id.tScroll);  

            /** 
             * 動態設置坐標及寬和高，也可以忽略，在配置文件中設置 
             */  
            AbsoluteLayout.LayoutParams lp = (AbsoluteLayout.LayoutParams) tv  
                    .getLayoutParams();  
            lp.x = 300;  
            lp.y = 300;  
            lp.width = 500;  
            lp.height = 170;  

            tv.setTextSize(16);  
            tv.setTextColor(Color.WHITE);  
            tv.setGravity(Gravity.LEFT);  

            tv.setText(welcomeWords.get(curIndex));  

            h.postDelayed(r, 3000);  
        }  

        Handler h = new Handler();   
        int i = 0;  
        Runnable r = new Runnable() {  

            @Override  
            public void run() {  
                int height = tv.getHeight();  
                int scrollY = tv.getScrollY();  
                int lineHeight = tv.getLineHeight();  
                int lineCount = tv.getLineCount();//總行數  
                /** 
                 * textView不可見內容的高度，可以理解為偏移位移 
                 */  
                int maxY = (tv.getLineCount() * tv.getLineHeight()  
                        + tv.getPaddingTop() + tv.getPaddingBottom())  
                        - tv.getHeight();  

                Log.e("=maxY=", maxY+"");  
                Log.e("=height=", height+"");  
                Log.e("=lineCount=", tv.getLineCount()+"");  

                double viewCount = Math.floor(height / lineHeight);//可見區域最大顯示多少行  
                if (lineCount > viewCount) {//總行數大于可見區域顯示的行數時則滾動  

                    if (scrollY >= maxY) {  
                        tv.scrollBy(0, -maxY);  
                    } else {  
                        tv.scrollBy(0, lineHeight);  
                    }  
                    h.postDelayed(this, 3000);  
                }  

            }  

        };  

        public boolean onKeyDown(int keyCode, KeyEvent event) {  

            switch (keyCode) {  
            case KeyEvent.KEYCODE_DPAD_UP:  

                break;  
            case KeyEvent.KEYCODE_DPAD_DOWN:  

                break;  
            case KeyEvent.KEYCODE_DPAD_RIGHT:  

                handle();  
                break;  
            case KeyEvent.KEYCODE_DPAD_LEFT:  

                handle();  
                break;  
            case KeyEvent.KEYCODE_DPAD_CENTER:  
                handle();  
                break;  
            case KeyEvent.KEYCODE_ENTER:  
                handle();  
                break;  
            case KeyEvent.KEYCODE_BACK:  
                finish();  

                break;  
            default:  

            }  
            return super.onKeyDown(keyCode, event);  
        }  

        public void handle() {  

            h.removeCallbacks(r);  



            curIndex = (curIndex + 1) % 2;  

            tv.setText(welcomeWords.get(curIndex));  

            h.postDelayed(r, 3000);  

        }  

        @Override  
        public void onDestroy() {  
            super.onDestroy();  
            h.removeCallbacks(r);  
        }  

    }