当我添加更多文本行时,如何使TextView自动滚动？

Question

所以,我有一个像这样的TextView:

<TextView
    android:layout_width="fill_parent"
    android:layout_height="140.7dp"
    android:id="@+id/terminalOutput"
    android:layout_marginBottom="0.0dp"
    android:scrollbars="vertical"
    android:scrollbarAlwaysDrawVerticalTrack="true"
    android:maxLines="8" />

我将它用作一种运行日志,显示给用户,以便他们可以监视大约需要3分钟的任务进度.但是,一旦我超过8行,文本就会消失.这对用户来说是不直观的,因为除了通过向下滚动手动轮询之外,他们无法知道它已经离开了屏幕.

我怎么能这样做,以便每次我添加一些文本到这个TextView我让它向下滚动尽可能低？

此外,这是在Xamarin Android,但我不认为这是相关的.在它和Java之间进行转换很容易

Answer 1

从您的代码中,有两个步骤:

步骤1

虽然您在Xamarin Android中编码,但是在xxxActivity.java中的Java中,对于terminalOutput调用必须是这样的

TextView outputText = (TextView) findViewById(R.id.terminalOutput);
outputText.setMovementMethod(new ScrollingMovementMethod());

方法setMovementMethod()通过参数ScrollingMovementMethod()是噱头.

第2步

在Java-Android的布局中,如上面的TextView声明的activity_xxx.xml中必须要添加这个

android:gravity="bottom"

当你像这样在outputText中添加新行时

outputText.append("\n"+"New text line.");

它会自动滚动到最后一行,这些都是你需要的魔力.

Answer 2

根据这里的答案,在Android中制作TextView Scrollable

您实际上不需要使用ScrollView.

只需设置

android:maxLines = "AN_INTEGER"

android:scrollbars =布局的xml文件中TextView的"垂直"属性.

然后使用:

yourTextView.setMovementMethod(new ScrollingMovementMethod());

在你的代码中.

那可行..

Answer 3

这些答案都不是我想要的,所以我想出了这个.

textView.append(log);

while (textView.canScrollVertically(1)) {
    textView.scrollBy(0, 10);
}

不要忘记在滚动之前设置移动方法

textView.setMovementMethod(new ScrollingMovementMethod());

Answer 4

有同样的问题.从这个和类似的讨论中尝试了几个决定,没有任何效果.解决这个问题:

edtConsoleText.setSelection(edtConsoleText.getText().length());

每一次之后.append().

Answer 5

您可以尝试2种解决方案:

1. 将TextView放在ScrollView中

   <ScrollView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content">
           <TextView
           android:id="@+id/TextView01"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="Your Text" >
       </TextView>
   </ScrollView>
   

2. 使用自定义滚动TextView(与传统TextView相同,但它可以滚动)

   import android.content.Context;
   import android.graphics.Rect;
   import android.text.TextPaint;
   import android.util.AttributeSet;
   import android.view.animation.LinearInterpolator;
   import android.widget.Scroller;
   import android.widget.TextView;
   
    public class ScrollTextView extends TextView {
   
   
       // scrolling feature
       private Scroller mSlr;
   
       // milliseconds for a round of scrolling
       private int mRndDuration = 250;
   
       // the X offset when paused
       private int mXPaused = 0;
   
       // whether it's being paused
       private boolean mPaused = true;
   
       /*
        * constructor
        */
       public ScrollTextView(Context context) {
           this(context, null);
           // customize the TextView
           setSingleLine();
           setEllipsize(null);
           setVisibility(INVISIBLE);
       }
   
       /*
        * constructor
        */
       public ScrollTextView(Context context, AttributeSet attrs) {
           this(context, attrs, android.R.attr.textViewStyle);
           // customize the TextView
           setSingleLine();
           setEllipsize(null);
           setVisibility(INVISIBLE);
       }
   
       /*
        * constructor
        */
       public ScrollTextView(Context context, AttributeSet attrs, int defStyle) {
           super(context, attrs, defStyle);
           // customize the TextView
           setSingleLine();
           setEllipsize(null);
           setVisibility(INVISIBLE);
       }
   
       /**
        * begin to scroll the text from the original position
        */
       public void startScroll() {
           // begin from the very right side
           mXPaused = -1 * getWidth();
           // assume it's paused
           mPaused = true;
           resumeScroll();
       }
   
       /**
        * resume the scroll from the pausing point
        */
       public void resumeScroll() {
   
           if (!mPaused)
               return;
   
           // Do not know why it would not scroll sometimes
           // if setHorizontallyScrolling is called in constructor.
           setHorizontallyScrolling(true);
   
           // use LinearInterpolator for steady scrolling
           mSlr = new Scroller(this.getContext(), new LinearInterpolator());
           setScroller(mSlr);
   
           int scrollingLen = calculateScrollingLen();
           int distance = scrollingLen - (getWidth() + mXPaused);
           int duration = (new Double(mRndDuration * distance * 1.00000
                   / scrollingLen)).intValue();
   
           setVisibility(VISIBLE);
           mSlr.startScroll(mXPaused, 0, distance, 0, duration);
           mPaused = false;
       }
   
       /**
        * calculate the scrolling length of the text in pixel
        * 
        * @return the scrolling length in pixels
        */
       private int calculateScrollingLen() {
           TextPaint tp = getPaint();
           Rect rect = new Rect();
           String strTxt = getText().toString();
           tp.getTextBounds(strTxt, 0, strTxt.length(), rect);
           int scrollingLen = rect.width() + getWidth();
           rect = null;
           return scrollingLen;
       }
   
       /**
        * pause scrolling the text
        */
       public void pauseScroll() {
           if (null == mSlr)
               return;
   
           if (mPaused)
               return;
   
           mPaused = true;
   
           // abortAnimation sets the current X to be the final X,
           // and sets isFinished to be true
           // so current position shall be saved
           mXPaused = mSlr.getCurrX();
   
           mSlr.abortAnimation();
       }
   
       @Override
       /*
        * override the computeScroll to restart scrolling when finished so as that
        * the text is scrolled forever
        */
       public void computeScroll() {
           super.computeScroll();
   
           if (null == mSlr)
               return;
   
           if (mSlr.isFinished() && (!mPaused)) {
               this.startScroll();
           }
       }
   
       public int getRndDuration() {
           return mRndDuration;
       }
   
       public void setRndDuration(int duration) {
           this.mRndDuration = duration;
       }
   
       public boolean isPaused() {
           return mPaused;
       }
    }
   

如何使用:

ScrollTextView scrolltext = (ScrollTextView) findViewById(R.id.YourTextView);

(ScrollTextView类源:http://bear-polka.blogspot.com/2009/01/scrolltextview-scrolling-textview-for.html)