很棒的Android弹幕效果实例

public class BarrageItem { 
 
 public TextView textView; 
 
 public int textColor; 
 
 public String text; 
 
 public int textSize; 
 
 // 移动速度 
 public int moveSpeed; 
 
 // 垂直方向显示的位置 
 public int verticalPos; 
 
 // 字体显示占据的宽度 
 public int textMeasuredWidth; 
 
} 

public class BarrageView extends RelativeLayout { 
 
 private Context mContext; 
 
 private BarrageHandler mHandler = new BarrageHandler(); 
 
 private Random random = new Random(System.currentTimeMillis()); 
 
 // 两个弹幕的最小间隔时间 
 private static final long BARRAGE_GAP_MIN_DURATION = 1000; 
 
 // 两个弹幕的最大间隔时间 
 private static final long BARRAGE_GAP_MAX_DURATION = 2000; 
 
 // 速度,ms 
 private int maxSpeed = 12000; 
 
 // 速度,ms 
 private int minSpeed = 8000; 
 
 // 文字最大值 
 private int maxSize = 50; 
 
 // 文字最小值 
 private int minSize = 10; 
 
 private int totalHeight = 0; 
 
 private int lineHeight = 0;// 每一行弹幕的高度 
 
 private int totalLine = 0;// 弹幕的行数 
 
 private String[] itemText = { "他们都说蔡睿智很帅,但他总觉得自己很丑", 
   "他们都说蔡睿智是男神,但他只觉得自己是男生", "蔡睿智不是男神,蔡睿智是男生", "蔡睿智貌似是gay", "蔡睿智是弯的", 
   "蔡睿智是弯的,还好现在掰回来了", "他承受了他这个年纪不该有的机智与帅气，他好累", 
   "我恨自己的颜值，我觉得自己的才华才是吸引别人的地方", "他为什么对妹子不感兴趣呢？为什么？", "他为什么不想谈恋爱","他不会去爱别人,同时也不希望别人去爱他,他已经习惯一个人了", 
   "他的心里是否住着一个苍老的小孩", "他的世界一直就是他和他的影子,直到遇到她", "她引导他走出了自己的世界，改变他的很多看法", 
   "他渐渐的发现自己已经离不开他,他选择不再去压抑自己", "因为他已经不是那个无能为力的年纪","她经常说他 高冷,现在越来越觉得他恨闷骚","开始他一直与她保持朋友距离,但他发现自己根本作不到"}; 
 private int textCount; 
 
 public BarrageView(Context context, AttributeSet attrs, int defStyleAttr) { 
  super(context, attrs, defStyleAttr); 
  mContext = context; 
  _init(); 
 } 
 
 public BarrageView(Context context, AttributeSet attrs) { 
  this(context, null, 0); 
 
 } 
 
 public BarrageView(Context context) { 
  this(context, null); 
 
 } 
 
 private void _init() { 
  textCount = itemText.length; 
  int duration = (int) ((BARRAGE_GAP_MAX_DURATION - BARRAGE_GAP_MIN_DURATION) * Math 
    .random()); 
  mHandler.sendEmptyMessageDelayed(0, duration); 
 } 
 
 @Override 
 public void onWindowFocusChanged(boolean hasWindowFocus) { 
  super.onWindowFocusChanged(hasWindowFocus); 
  totalHeight = getMeasuredHeight(); 
  lineHeight = getLineHeight(); 
  totalLine = totalHeight / lineHeight; 
 } 
 
 private void generateItem() { 
  BarrageItem item = new BarrageItem(); 
  String tx = itemText[(int) (Math.random() * textCount)]; 
  int sz = (int) (minSize + (maxSize - minSize) * Math.random()); 
  item.textView = new TextView(mContext); 
  item.textView.setText(tx); 
  item.textView.setTextSize(sz); 
  item.textView.setTextColor(Color.rgb(random.nextInt(256), 
    random.nextInt(256), random.nextInt(256))); 
  item.textMeasuredWidth = (int) getTextWidth(item, tx, sz); 
  item.moveSpeed = (int) (minSpeed + (maxSpeed - minSpeed) 
    * Math.random()); 
  if (totalLine == 0) { 
   totalHeight = getMeasuredHeight(); 
   lineHeight = getLineHeight(); 
   totalLine = totalHeight / lineHeight; 
  } 
  item.verticalPos = random.nextInt(totalLine) * lineHeight; 
  showBarrageItem(item); 
 } 
 
 private void showBarrageItem(final BarrageItem item) { 
  int leftMargin = this.getRight() - this.getLeft() 
    - this.getPaddingLeft(); 
  LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, 
    LayoutParams.WRAP_CONTENT); 
  params.addRule(RelativeLayout.ALIGN_PARENT_TOP); 
  params.topMargin = item.verticalPos; 
  this.addView(item.textView, params); 
  Animation anim = generateTranslateAnim(item, leftMargin); 
  anim.setAnimationListener(new Animation.AnimationListener() { 
 
   @Override 
   public void onAnimationStart(Animation arg0) { 
 
   } 
 
   @Override 
   public void onAnimationRepeat(Animation arg0) { 
     
   } 
 
   @Override 
   public void onAnimationEnd(Animation arg0) { 
    item.textView.clearAnimation(); 
    BarrageView.this.removeView(item.textView); 
   } 
  }); 
  item.textView.startAnimation(anim); 
 } 
 
 private TranslateAnimation generateTranslateAnim(BarrageItem item, 
   int leftMargin) { 
  TranslateAnimation anim = new TranslateAnimation(leftMargin, 
    -item.textMeasuredWidth, 0, 0); 
  anim.setDuration(item.moveSpeed); 
  anim.setInterpolator(new AccelerateDecelerateInterpolator()); 
  anim.setFillAfter(true); 
  return anim; 
 } 
 
 /** 
  * 计算TextView中字符串的长度 
  * 
  * @param item 
  * @param text 
  *   要计算的字符串 
  * @param Size 
  *   字体大小 
  * @return TextView中字符串的长度 
  */ 
 public float getTextWidth(BarrageItem item, String text, float Size) { 
  Rect bounds = new Rect(); 
  TextPaint paint; 
  paint = item.textView.getPaint(); 
  paint.getTextBounds(text, 0, text.length(), bounds); 
  return bounds.width(); 
 } 
 
 /** 
  * 获得每一行弹幕的最大高度 
  */ 
 private int getLineHeight() { 
  BarrageItem item = new BarrageItem(); 
  String tx = itemText[0]; 
  item.textView = new TextView(mContext); 
  item.textView.setText(tx); 
  item.textView.setTextSize(maxSize); 
 
  Rect bounds = new Rect(); 
  TextPaint paint; 
  paint = item.textView.getPaint(); 
  paint.getTextBounds(tx, 0, tx.length(), bounds); 
  return bounds.height(); 
 } 
 
 class BarrageHandler extends Handler { 
  @Override 
  public void handleMessage(Message msg) { 
   super.handleMessage(msg); 
   generateItem(); 
   // 每个弹幕产生的时间随机 
   int duration = (int) ((BARRAGE_GAP_MAX_DURATION - BARRAGE_GAP_MIN_DURATION) * Math 
     .random()); 
   this.sendEmptyMessageDelayed(0, duration); 
  } 
 } 
 
} 

<span style="font-size:18px;">public class MainActivity extends Activity { 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_main); 
 } 
}</span>