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>