如何从左到右应用textview的颜色过渡android？

Question

嗨，我需要为textview应用颜色过渡，然后移动到下一个屏幕。我试过的是我尝试使用静态颜色textview使用spannable字符串，但我无法应用在textview上移动的动态颜色过渡。这是我尝试过的。

public class AppActivity extends Activity { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    TextView tv = (TextView) findViewById(R.id.text); 
    Spannable text = new SpannableStringBuilder("Loading.."); 
    setSpan(tv, text); 
    tv.setText(text); 
} 

private void setSpan(TextView tv, Spannable text) { 
    int blueColor = 0xff0000ff; 
    int redColor = 0xffff0000; 
    ForegroundColorSpan blue = new ForegroundColorSpan(blueColor); 
    ForegroundColorSpan red = new ForegroundColorSpan(redColor); 
    HalfColorApply o = new HalfColorApply("o", tv, blueColor, redColor); 
    text.setSpan(blue, 0, 1, 0); 
    text.setSpan(o, 1, 2, 0); 
    text.setSpan(red, 2, text.length(), 0); 
    } 

class HalfColorApply extends DynamicDrawableSpan { 
    private final static String TAG = "DrawableSpanTest"; 
    Picture mPicture; 

    public HalfColorApply(String text, TextView tv, int c0, int c1) { 
     super(ALIGN_BASELINE); 
     mPicture = new Picture(); 
     TextPaint p = tv.getPaint(); 
     Rect bounds = new Rect(); 
     p.getTextBounds(text, 0, text.length(), bounds); 
     float width = p.measureText(text); 
     float height = bounds.height(); 
     float y = height; 
     Canvas c = mPicture.beginRecording((int) width, (int) height); 
     c.save(Canvas.CLIP_SAVE_FLAG); 
     // c.drawColor(0x[masked]); 
     p = new TextPaint(p); 
     p.setColor(c0); 
     c.clipRect(0, 0, width/2, height, Region.Op.REPLACE); 
     c.drawText(text, 0, y, p); 
     p.setColor(c1); 
     c.clipRect(width/2, 0, width, height, Region.Op.REPLACE); 
     c.drawText(text, 0, y, p); 
     c.restore(); 
     mPicture.endRecording(); 
    } 

    @Override 
    public Drawable getDrawable() { 
     PictureDrawable d = new PictureDrawable(mPicture); 
     d.setBounds(0, 0, mPicture.getWidth(), mPicture.getHeight()); 
     return d; 
    } 
} 
} 

这里是截图，我在一个固定的特定文本应用。我需要使颜色过渡在textview上移动。

在此先感谢。

Answer 1

找到解决办法。

public class SplashActivity extends Activity { 
private TextView textView; 
private Handler handler; 
private long startTime, currentTime, finishedTime = 0L; 
private int duration = 22000/4;// 1 character is equal to 1 second. if want to 
         // reduce. can use as divide 
         // by 2,4,8 
private int endTime = 0; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 

    super.onCreate(savedInstanceState); 
    this.requestWindowFeature(Window.FEATURE_NO_TITLE); 
    setContentView(R.layout.test); 
    textView = (TextView) findViewById(R.id.textView1); 
    textView.setText("Loading.Please wait...");// length of string is 22 
    handler = new Handler(); 
    startTime = Long.valueOf(System.currentTimeMillis()); 
    currentTime = startTime; 

    handler.postDelayed(new Runnable() { 
     @Override 
     public void run() { 

      currentTime = Long.valueOf(System.currentTimeMillis()); 
      finishedTime = Long.valueOf(currentTime) 
        - Long.valueOf(startTime); 

      if (finishedTime >= duration + 30) { 
       Toast.makeText(SplashActivity.this, "Move to next screen", 
         Toast.LENGTH_LONG).show(); 
      } else { 
       endTime = (int) (finishedTime/250);// divide this by 
       // 1000,500,250,125 
       Spannable spannableString = new SpannableString(textView 
         .getText()); 
       spannableString.setSpan(new ForegroundColorSpan(
         Color.YELLOW), 0, endTime, 
         Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 

       textView.setText(spannableString); 
       handler.postDelayed(this, 10); 
      } 
     } 
    }, 10); 
} 

}