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>