我是echo回声的忠实粉丝，里面的各种3D音效真是美滴很美滴很。这个App的开发组是完美主义，被深深吸引无法自拔。尤其是弹幕的神评论更加搞笑。今天，我就仿着echo的弹幕纯手打了一个效果出来。
Talk is cheap,show you the code
是时候来一发炸裂的开场了：
giphy.gif
写这个功能之前，我低下头深深沉思，我要做什么功能呢，要怎么做到呢？写程序要一步一步来，步子大了会扯着蛋，于是我在纸上列出：
1.创建一个Relativelayout,在里面添加一个moveView(每一个弹幕view)。
2.写下这个moveView和该布局。
3.给moveView添加translation动画从右往左跑出，动画开始添加，动画结束移除该view。
4.用定时器不停创建多个moveView从右往左动画。
5.在根据Relativelayout的高度范围，创建随机高度，设置给moveView的上边界距离。
6.创建数据源，包括头像id，名字，弹幕文字内容
7.设置随机出现间隔时间；设置背景图（这里我是截的背景图）
我用双手成就我的设想：
1.创建MoveView布局
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center_vertical">
<ImageView
android:id="@+id/avator"
android:layout_width="30dp"
android:layout_height="30dp"
android:background="@mipmap/internet_star"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:background="@drawable/shape_text">
<TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Jack ma"
android:textColor="#2ecc71"/>
<TextView
android:id="@+id/tv_content"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:text="哈哈哈"
android:singleLine="true"
android:background="@drawable/shape_text"
android:textColor="#000" />
</LinearLayout>
</LinearLayout>
2.创建moveview，传入Relativelayout高度随机设置params.topMargin属性值，即随机垂直高度出现。
public class MoveView extends LinearLayout{
private View rootView;
private ImageView ivAvator;
private TextView tvName;
private TextView tvContent;
public MoveView(Context context, DanmuBean danmuBean) {
super(context);
rootView = inflate(context,R.layout.item,null);
addView(rootView);
init(danmuBean);
}
private void init(DanmuBean danmuBean) {
ivAvator = rootView.findViewById(R.id.avator);
tvName = rootView.findViewById(R.id.tv_name);
tvContent = rootView.findViewById(R.id.tv_content);
ivAvator.setImageResource(danmuBean.getAvatorId());
tvName.setText(danmuBean.getUserName());
tvContent.setText(danmuBean.getContent());
}
/**
* 设置随机出现垂直位置
*/
public void randomVerticalPos(int heightPixels){
int randonTop = (int) (Math.random()*heightPixels);
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) getLayoutParams();
params.topMargin = randonTop;
setLayoutParams(params);
}
}
3.随机设置Translationg动画的duration，即实现随机移动速度；
private void startTranslateAnim(final View view){
int randomDuration = (int) (Math.random()*2000 + 7000);
TranslateAnimation anim = new TranslateAnimation(widthPixels,-widthPixels,0,0);
anim.setDuration(randomDuration);
anim.setAnimationListener(new Animation.AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {
}
@Override
public void onAnimationEnd(Animation animation) {
removeView(view);
}
@Override
public void onAnimationRepeat(Animation animation) {
}
});
view.startAnimation(anim);
}
4.handler随机间隔创建moveview。
private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
addTextView();
//弹幕出现间隔时间400-700ms
int randomDelay = (int) (Math.random()*300+400);
handler.sendEmptyMessageDelayed(0,randomDelay);
}
};
private void addTextView(){
if(curPos == datas.size()){ //循环播放
curPos = 0;
}
MoveView moveView = new MoveView(getContext(),datas.get(curPos++));
addView(moveView);
moveView.randomVerticalPos(heightPixels);
startTranslateAnim(moveView);
}
5.模拟网络请求弹幕数据列表，这里包括，头像、用户名、弹幕内容。
private List loadData(){
ArrayList<DanmuBean> datas = new ArrayList<>();
datas.add(new DanmuBean(0,R.mipmap.internet_star,"小强","女神我爱你！"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_funny,"Jack ma","妈妈问我为什么跪着听歌"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_lori,"习大大","歌词特别美"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_robot,"宝强","全世界都安静了"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_uncle,"宝宝","听到放不下耳机，听到耳朵痛都不放下，哈哈哈"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"我是大神","中国好声音，I want you"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"茜茜","一天脑子里都在唱这首歌"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_funny,"Bangbangbang","有故事，好听"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_uncle,"stalse","我就是为了你开的会员"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"hehe","太好听了.."));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_robot,"小强","女神我爱你！"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_uncle,"Jack ma","妈妈问我为什么跪着听歌"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"习大大","歌词特别美"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_funny,"宝强","全世界都安静了"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"宝宝","听到放不下耳机，听到耳朵痛都不放下，哈哈哈"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"我是大神","中国好声音，I want you"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_robot,"茜茜","一天脑子里都在唱这首歌"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_uncle,"Bangbangbang","有故事，好听"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"stalse","我就是为了你开的会员"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_funny,"hehe","太好听了.."));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"小强","女神我爱你！"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_robot,"Jack ma","妈妈问我为什么跪着听歌"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_uncle,"习大大","歌词特别美"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"宝强","全世界都安静了"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_funny,"宝宝","听到放不下耳机，听到耳朵痛都不放下，哈哈哈"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"我是大神","中国好声音，I want you"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_uncle,"茜茜","一天脑子里都在唱这首歌"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"Bangbangbang","有故事，好听"));
datas.add(new DanmuBean(0,R.mipmap.make_music_voice_changer_funny,"stalse","我就是为了你开的会员"));
datas.add(new DanmuBean(0,R.mipmap.internet_star,"hehe","太好听了.."));
return datas;
}
盼望着，盼望着，一直都盼望着拿时间写一个弹幕自己来用，今天终于写了。好了，咱们下期节目再见！
