上面效果图中白色的背景就是弹幕本身,是一个自定义的FrameLayout,我这里是为了更好的展示弹幕的位置才设置成了白色,当然如果是叠加在VideoView上的话,就需要设置成透明色了.
制作弹幕需要考虑以下几点问题:
1.弹幕的大小可以随意调整
2.弹幕内移动的item(或者称字幕)出现的位置,水平方向是从屏幕右边移动到屏幕左边,垂直方向是不能超出弹幕本身的高度的.
3.字幕移除屏幕后,需要将对应item(字幕)从其父容器(弹幕)中移除.
4.如果字幕出现的垂直方向的高度是随机的,那么还需要避免字幕重叠的情况.
ok,下面是弹幕自定义view的代码:
publicclassDanmuView extendsFrameLayout {
privatestaticfinalString TAG = "DanmuView";
privatestaticfinallongDEFAULT_ANIM_DURATION = 6000; //默认每个动画的播放时长
privatestaticfinallongDEFAULT_QUERY_DURATION = 3000; //遍历弹幕的默认间隔
privateLinkedList<View> mViews = newLinkedList<>();//弹幕队列
privatebooleanisQuerying;
privateintmWidth;//弹幕的宽度
privateintmHeight;//弹幕的高度
privateHandler mUIHandler = newHandler();
privatebooleanTopDirectionFixed;//弹幕顶部的方向是否固定
privateHandler mQueryHandler;
privateintmTopGravity = Gravity.CENTER_VERTICAL;//顶部方向固定时的默认对齐方式
publicvoidsetHeight(intheight) {
mHeight = height;
}
publicvoidsetWidth(intwidth) {
mWidth = width;
}
publicvoidsetTopGravity(intgravity) {
this.mTopGravity = gravity;
}
publicvoidadd(List<Danmu> danmuList) {
for(inti = 0; i < danmuList.size(); i++) {
Danmu danmu = danmuList.get(i);
addDanmuToQueue(danmu);
}
}
publicvoidadd(Danmu danmu) {
addDanmuToQueue(danmu);
}
publicDanmuView(Context context) {
this(context, null);
}
publicDanmuView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
publicDanmuView(Context context, AttributeSet attrs, intdefStyleAttr) {
super(context, attrs, defStyleAttr);
HandlerThread thread = newHandlerThread("query");
thread.start();
//循环取出弹幕显示
mQueryHandler = newHandler(thread.getLooper()) {
@Override
publicvoidhandleMessage(Message msg) {
finalView view = mViews.poll();
if(null!= view) {
mUIHandler.post(newRunnable() {
@Override
publicvoidrun() {
//添加弹幕
showDanmu(view);
}
});
}
sendEmptyMessageDelayed(0, DEFAULT_QUERY_DURATION);
}
};
}
/**
* 将要展示的弹幕添加到队列中
*
* @param danmu
*/
privatevoidaddDanmuToQueue(Danmu danmu) {
if(null!= danmu) {
finalView view = View.inflate(getContext(), R.layout.layout_danmu, null);
TextView usernameTv = (TextView) view.findViewById(R.id.tv_username);
TextView infoTv = (TextView) view.findViewById(R.id.tv_info);
ImageView headerIv = (ImageView) view.findViewById(R.id.iv_header);
usernameTv.setText(danmu.getUserName());//昵称
infoTv.setText(danmu.getInfo());//信息
Glide.with(getContext()).//头像
load(danmu.getHeaderUrl()).
transform(newCropCircleTransformation(getContext())).into(headerIv);
view.measure(0, 0);
//添加弹幕到队列中
mViews.offerLast(view);
}
}
/**
* 播放弹幕
*
* @param topDirectionFixed 弹幕顶部的方向是否固定
*/
publicvoidstartPlay(booleantopDirectionFixed) {
this.TopDirectionFixed = topDirectionFixed;
if(mWidth == 0|| mHeight == 0) {
getViewTreeObserver().addOnGlobalLayoutListener(newViewTreeObserver.OnGlobalLayoutListener() {
@SuppressLint("NewApi")
@Override
publicvoidonGlobalLayout() {
getViewTreeObserver().removeOnGlobalLayoutListener(this);
if(mWidth == 0) mWidth = getWidth() - getPaddingLeft() - getPaddingRight();
if(mHeight == 0) mHeight = getHeight() - getPaddingTop() - getPaddingBottom();
if(!isQuerying) {
mQueryHandler.sendEmptyMessage(0);
}
}
});
} else{
if(!isQuerying) {
mQueryHandler.sendEmptyMessage(0);
}
}
}
/**
* 显示弹幕,包括动画的执行
*
* @param view
*/
privatevoidshowDanmu(finalView view) {
isQuerying = true;
Log.d(TAG, "mWidth:"+ mWidth + " mHeight:"+ mHeight);
finalLayoutParams lp = newLayoutParams(view.getMeasuredWidth(), view.getMeasuredHeight());
lp.leftMargin = mWidth;
if(TopDirectionFixed) {
lp.gravity = mTopGravity | Gravity.LEFT;
} else{
lp.gravity = Gravity.LEFT | Gravity.TOP;
lp.topMargin = getRandomTopMargin(view);
}
view.setLayoutParams(lp);
view.setTag(lp.topMargin);
//设置item水平滚动的动画
ValueAnimator animator = ValueAnimator.ofInt(mWidth, -view.getMeasuredWidth());
animator.addUpdateListener(newValueAnimator.AnimatorUpdateListener() {
@Override
publicvoidonAnimationUpdate(ValueAnimator animation) {
lp.leftMargin = (int) animation.getAnimatedValue();
view.setLayoutParams(lp);
}
});
addView(view);//显示弹幕
animator.setDuration(DEFAULT_ANIM_DURATION);
animator.setInterpolator(newLinearInterpolator());
animator.start();//开启动画
animator.addListener(newAnimatorListenerAdapter() {
@Override
publicvoidonAnimationEnd(Animator animation) {
view.clearAnimation();
existMarginValues.remove(view.getTag());//移除已使用过的顶部边距
removeView(view);//移除弹幕
animation.cancel();
}
});
}
//记录当前仍在显示状态的弹幕的垂直方向位置（避免重复）
privateSet<Integer> existMarginValues = newHashSet<>();
privateintlinesCount;
privateintrange = 10;
privateintgetRandomTopMargin(View view) {
//计算可用的行数
linesCount = mHeight / view.getMeasuredHeight();
if(linesCount <= 1) {
linesCount = 1;
}
Log.d(TAG, "linesCount:"+ linesCount);
//检查重叠
while(true) {
intrandomIndex = (int) (Math.random() * linesCount);
intmarginValue = randomIndex * (mHeight / linesCount);
//边界检查
if(marginValue > mHeight - view.getMeasuredHeight()) {
marginValue = mHeight - view.getMeasuredHeight() - range;
}
if(marginValue == 0) {
marginValue = range;
}
if(!existMarginValues.contains(marginValue)) {
existMarginValues.add(marginValue);
Log.d(TAG, "marginValue:"+ marginValue);
returnmarginValue;
}
}
}
}
弹幕实体类:
/**
* Created by dell on 2016/9/28.
*/
publicclassDanmu {
privateString headerUrl;//头像
privateString userName;//昵称
privateString info;//信息
publicString getHeaderUrl() {
returnheaderUrl;
}
publicvoidsetHeaderUrl(String headerUrl) {
this.headerUrl = headerUrl;
}
publicString getUserName() {
returnuserName;
}
publicvoidsetUserName(String userName) {
this.userName = userName;
}
publicString getInfo() {
returninfo;
}
publicvoidsetInfo(String info) {
this.info = info;
}
}
测试类,MainActivity
publicclassMainActivity extendsAppCompatActivity {
DanmuView mDanmuView;
EditText mMsgEdt;
Button mSendBtn;
Handler mDanmuAddHandler;
booleancontinueAdd;
intcounter;
@Override
protectedvoidonResume() {
super.onResume();
mDanmuView.startPlay(true);//true表示弹幕的垂直方向是固定的,false则随机
continueAdd = true;
mDanmuAddHandler.sendEmptyMessageDelayed(0, 6000);
}
@Override
protectedvoidonPause() {
super.onPause();
continueAdd = false;
mDanmuAddHandler.removeMessages(0);
}
@Override
protectedvoidonCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
initListener();
}
privatevoidinitView() {
mDanmuView = (DanmuView) findViewById(R.id.danmuView);
mMsgEdt = (EditText) findViewById(R.id.edt_msg);
mSendBtn = (Button) findViewById(R.id.btn_send);
}
privatevoidinitData() {
List<Danmu> danmuList = newArrayList<>();
for(inti = 0; i < 3; i++) {
Danmu danmu = newDanmu();
danmu.setHeaderUrl("http://tupian.qqjay.com/tou3/2016/0725/cb00091099ffbf09f4861f2bbb5dd993.jpg");
danmu.setUserName("Mr.chen"+ i);
danmu.setInfo("我是弹幕啊,不要问我为什么不可以那么长!!!");
danmuList.add(danmu);
}
mDanmuView.add(danmuList);
//下面是模拟每秒添加一个弹幕的过程
HandlerThread ht = newHandlerThread("send danmu");
ht.start();
mDanmuAddHandler = newHandler(ht.getLooper()) {
@Override
publicvoidhandleMessage(Message msg) {
runOnUiThread(newRunnable() {
@Override
publicvoidrun() {
Danmu danmu = newDanmu();
danmu.setHeaderUrl("http://tupian.qqjay.com/tou3/2016/0803/87a8b262a5edeff0e11f5f0ba24fb22f.jpg");
danmu.setUserName("Mr.new"+ (counter++));
danmu.setInfo("新的弹幕啊!!!新的弹幕啊!!!新的弹幕啊!!!新的弹幕啊!!!");
mDanmuView.add(danmu);
}
});
//继续添加
if(continueAdd) {
sendEmptyMessageDelayed(0, 1000);
}
}
};
}
privatevoidinitListener() {
//手动添加
mSendBtn.setOnClickListener(newView.OnClickListener() {
@Override
publicvoidonClick(View v) {
String msg = mMsgEdt.getText().toString().trim();
if(TextUtils.isEmpty(msg)) {
Toast.makeText(MainActivity.this, "亲,你想发送什么啊?", Toast.LENGTH_SHORT).show();
return;
}
mMsgEdt.setText("");
Danmu danmu = newDanmu();
danmu.setHeaderUrl("http://img0.imgtn.bdimg.com/it/u=2198087564,4037394230&fm=11&gp=0.jpg");
danmu.setUserName("I'am good man");
danmu.setInfo("我是新人:"+ msg);
mDanmuView.add(danmu);
}
});
}
}
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