Android弹幕实现：基于B站弹幕开源系统（3）-文本弹幕的完善和细节调整

Bertha 。 2023-10-17 12:08 38阅读 0赞

**Android弹幕实现：基于B站弹幕开源系统（3）**

本文在附录1，2的基础上再次对异步获取弹幕并显示弹幕完善逻辑和代码，集中在上层Java代码部分：

package zhangphil.danmaku;
    
    import android.app.Activity;
    import android.graphics.Color;
    import android.os.Bundle;
    import android.os.Handler;
    import android.os.Message;
    import android.text.TextUtils;
    import android.view.View;
    import android.widget.Button;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.concurrent.ConcurrentLinkedQueue;
    import java.util.concurrent.ScheduledThreadPoolExecutor;
    import java.util.concurrent.TimeUnit;
    
    import master.flame.danmaku.danmaku.model.BaseDanmaku;
    import master.flame.danmaku.danmaku.model.DanmakuTimer;
    import master.flame.danmaku.danmaku.model.IDisplayer;
    import master.flame.danmaku.danmaku.model.android.DanmakuContext;
    import master.flame.danmaku.ui.widget.DanmakuView;
    
    public class MainActivity extends Activity {
    
        private DanmakuView mDanmakuView;
        private DanmakuContext mContext;
        private AcFunDanmakuParser mParser;
    
        private final int MAX_DANMAKU_LINES = 8; //弹幕在屏幕显示的最大行数
    
        private ScheduledThreadPoolExecutor mScheduledThreadPoolExecutor = null;
        private ConcurrentLinkedQueue<DanmakuMsg> mQueue = null; //所有的弹幕数据存取队列，在这里做线程的弹幕取和存
        private ArrayList<DanmakuMsg> danmakuLists = null;//每次请求最新的弹幕数据后缓存list
    
        private final int WHAT_GET_LIST_DATA = 0xffa01;
        private final int WHAT_DISPLAY_SINGLE_DANMAKU = 0xffa02;
    
        private final int BASE_TIME = 400;
        private final int BASE_TIME_ADD = 100;
    
        //标志文本弹幕的序列号
        //区别不同弹幕
        private static int danmakuTextMsgId = 0;
    
        private final int[] colors = {Color.RED, Color.YELLOW, Color.BLUE, Color.GREEN, Color.CYAN, Color.DKGRAY};
    
        private Handler mDanmakuHandler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                super.handleMessage(msg);
    
                switch (msg.what) {
                    case WHAT_GET_LIST_DATA:
                        mDanmakuHandler.removeMessages(WHAT_GET_LIST_DATA);
    
                        if (danmakuLists != null && !danmakuLists.isEmpty()) {
                            mQueue.addAll(danmakuLists);
                            danmakuLists.clear();
    
                            if (!mQueue.isEmpty())
                                mDanmakuHandler.sendEmptyMessage(WHAT_DISPLAY_SINGLE_DANMAKU);
                        }
    
                        break;
    
                    case WHAT_DISPLAY_SINGLE_DANMAKU:
                        mDanmakuHandler.removeMessages(WHAT_DISPLAY_SINGLE_DANMAKU);
                        displayDanmaku();
                        break;
                }
            }
        };
    
        /**
         * 弹幕数据封装的类（bean）
         */
        private class DanmakuMsg {
            public String msg;
        }
    
        private void displayDanmaku() {
            boolean p = mDanmakuView.isPaused();
            //如果当前的弹幕由于Android生命周期的原因进入暂停状态，那么不应该不停的消耗弹幕数据
            //要知道，在这里发出一个handler消息，那么将会消费（删掉）ConcurrentLinkedQueue头部的数据
            if (!mQueue.isEmpty() && !p) {
                DanmakuMsg dm = mQueue.poll();
                if (!TextUtils.isEmpty(dm.msg)) {
                    addDanmaku(dm.msg, true);
                }
    
                mDanmakuHandler.sendEmptyMessageDelayed(WHAT_DISPLAY_SINGLE_DANMAKU, (long) (Math.random() * BASE_TIME) + BASE_TIME_ADD);
            }
        }
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            setContentView(R.layout.activity_main);
    
            danmakuLists = new ArrayList<>();
            mQueue = new ConcurrentLinkedQueue<>();
            mDanmakuView = (DanmakuView) findViewById(R.id.danmakuView);
    
            initDanmaku();
    
            mScheduledThreadPoolExecutor = new ScheduledThreadPoolExecutor(1);
            GetDanmakuMessageTask mTask = new GetDanmakuMessageTask();
            //延迟0秒执行，每隔若干秒周期执行一次任务
            mScheduledThreadPoolExecutor.scheduleAtFixedRate(mTask, 0, 5, TimeUnit.SECONDS);
    
            Button show = (Button) findViewById(R.id.show);
            Button hide = (Button) findViewById(R.id.hide);
            Button sendText = (Button) findViewById(R.id.sendText);
            Button pause = (Button) findViewById(R.id.pause);
            Button resume = (Button) findViewById(R.id.resume);
            Button clear = (Button) findViewById(R.id.clear);
    
            show.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mDanmakuView.show();
                }
            });
    
            hide.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mDanmakuView.hide();
                }
            });
    
            sendText.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    //每点击一次按钮发送一条弹幕
                    sendTextMessage();
                }
            });
    
            pause.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mDanmakuView.pause();
                }
            });
    
            resume.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mDanmakuView.resume();
                }
            });
    
            clear.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    clearDanmaku();
                }
            });
        }
    
        /**
         * 假设该线程任务模拟的就是从网络中取弹幕数据的耗时操作
         * 假设这些弹幕数据序列是有序的。
         */
        private class GetDanmakuMessageTask implements Runnable {
            @Override
            public void run() {
                danmakuLists.clear();
    
                int count = (int) (Math.random() * 50);
                for (int i = 0; i < count; i++) {
                    DanmakuMsg message = new DanmakuMsg();
                    message.msg = "弹幕:" + danmakuTextMsgId;
                    danmakuLists.add(message);
    
                    danmakuTextMsgId++;
                }
    
                if (!danmakuLists.isEmpty()) {
                    Message msg = mDanmakuHandler.obtainMessage();
                    msg.what = WHAT_GET_LIST_DATA;
                    mDanmakuHandler.sendMessage(msg);
                }
            }
        }
    
        /**
         * 驱动弹幕显示机制重新运作起来
         */
        private void resumeDanmaku() {
            if (!mQueue.isEmpty())
                mDanmakuHandler.sendEmptyMessageDelayed(WHAT_DISPLAY_SINGLE_DANMAKU, (int) (Math.random() * BASE_TIME) + BASE_TIME_ADD);
        }
    
        private void clearDanmaku() {
            if (danmakuLists != null && !danmakuLists.isEmpty()) {
                danmakuLists.clear();
            }
    
            if (mQueue != null && !mQueue.isEmpty())
                mQueue.clear();
    
            mDanmakuView.clearDanmakusOnScreen();
            mDanmakuView.clear();
        }
    
        private void initDanmaku() {
            mContext = DanmakuContext.create();
    
            // 设置最大显示行数
            HashMap<Integer, Integer> maxLinesPair = new HashMap<>();
            maxLinesPair.put(BaseDanmaku.TYPE_SCROLL_RL, MAX_DANMAKU_LINES); // 滚动弹幕最大显示5行
    
            // 设置是否禁止重叠
            HashMap<Integer, Boolean> overlappingEnablePair = new HashMap<>();
            overlappingEnablePair.put(BaseDanmaku.TYPE_SCROLL_RL, true);
            overlappingEnablePair.put(BaseDanmaku.TYPE_FIX_TOP, true);
    
            //普通文本弹幕也描边设置样式
            //如果是图文混合编排编排，最后不要描边
            mContext.setDanmakuStyle(IDisplayer.DANMAKU_STYLE_STROKEN, 10) //描边的厚度
                    .setDuplicateMergingEnabled(false)
                    .setScrollSpeedFactor(1.2f) //弹幕的速度。注意！此值越小，速度越快！值越大，速度越慢。// by phil
                    .setScaleTextSize(1.2f)  //缩放的值
    //        .setCacheStuffer(new BackgroundCacheStuffer())  // 绘制背景使用BackgroundCacheStuffer
                    .setMaximumLines(maxLinesPair)
                    .preventOverlapping(overlappingEnablePair);
    
            mParser = new AcFunDanmakuParser();
            mDanmakuView.prepare(mParser, mContext);
    
            //mDanmakuView.showFPS(true);
            mDanmakuView.enableDanmakuDrawingCache(true);
    
            if (mDanmakuView != null) {
                mDanmakuView.setCallback(new master.flame.danmaku.controller.DrawHandler.Callback() {
                    @Override
                    public void updateTimer(DanmakuTimer timer) {
                    }
    
                    @Override
                    public void drawingFinished() {
    
                    }
    
                    @Override
                    public void danmakuShown(BaseDanmaku danmaku) {
                        //Log.d("弹幕文本", "danmakuShown text=" + danmaku.text);
                    }
    
                    @Override
                    public void prepared() {
                        mDanmakuView.start();
                    }
                });
            }
        }
    
        private void sendTextMessage() {
            addDanmaku("zhangphil@csdn: " + System.currentTimeMillis(), true);
        }
    
        private void addDanmaku(CharSequence cs, boolean islive) {
            BaseDanmaku danmaku = mContext.mDanmakuFactory.createDanmaku(BaseDanmaku.TYPE_SCROLL_RL);
            if (danmaku == null || mDanmakuView == null) {
                return;
            }
    
            danmaku.text = cs;
            danmaku.padding = 5;
            danmaku.priority = 0;  // 可能会被各种过滤器过滤并隐藏显示
            danmaku.isLive = islive;
            danmaku.setTime(mDanmakuView.getCurrentTime() + 1200);
            danmaku.textSize = 20f * (mParser.getDisplayer().getDensity() - 0.6f); //文本弹幕字体大小
            danmaku.textColor = getRandomColor(); //文本的颜色
            danmaku.textShadowColor = getRandomColor(); //文本弹幕描边的颜色
            //danmaku.underlineColor = Color.DKGRAY; //文本弹幕下划线的颜色
            danmaku.borderColor = getRandomColor(); //边框的颜色
    
            mDanmakuView.addDanmaku(danmaku);
        }
    
        @Override
        protected void onPause() {
            super.onPause();
            if (mDanmakuView != null && mDanmakuView.isPrepared()) {
                mDanmakuView.pause();
            }
        }
    
        @Override
        protected void onResume() {
            super.onResume();
            if (mDanmakuView != null && mDanmakuView.isPrepared() && mDanmakuView.isPaused()) {
                mDanmakuView.resume();
    
                //重新启动handler消息机制，触发弹幕显示
                //如果没有这一个方法，那么显示弹幕的机制将失灵（失去驱动）
                //这个方法就是重新激发弹幕显示的handler机制。
                resumeDanmaku();
            }
        }
    
        private void closeGetDanmakuMessage() {
            if (mScheduledThreadPoolExecutor != null)
                mScheduledThreadPoolExecutor.shutdown();
        }
    
        @Override
        protected void onDestroy() {
            super.onDestroy();
            if (mDanmakuView != null) {
                // dont forget release!
                mDanmakuView.release();
                mDanmakuView = null;
            }
    
            closeGetDanmakuMessage();
        }
    
        /**
         * 从一系列颜色中随机选择一种颜色
         *
         * @return
         */
        private int getRandomColor() {
            int i = ((int) (Math.random() * 10)) % colors.length;
            return colors[i];
        }
    }

代码运行结果如图：

![Center][]

附录：  
1，《Android弹幕实现：基于B站弹幕开源系统（1）》链接：[http://blog.csdn.net/zhangphil/article/details/68067100][http_blog.csdn.net_zhangphil_article_details_68067100]  
2,《Android弹幕实现：基于B站弹幕开源系统（2）》链接：[http://blog.csdn.net/zhangphil/article/details/68114226][http_blog.csdn.net_zhangphil_article_details_68114226]  
3，《Java ConcurrentLinkedQueue队列线程安全操作》链接：[http://blog.csdn.net/zhangphil/article/details/65936066][http_blog.csdn.net_zhangphil_article_details_65936066]

[Center]: https://img-blog.csdn.net/20170330123247348?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvemhhbmdwaGls/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[http_blog.csdn.net_zhangphil_article_details_68067100]: http://blog.csdn.net/zhangphil/article/details/68067100
[http_blog.csdn.net_zhangphil_article_details_68114226]: http://blog.csdn.net/zhangphil/article/details/68114226
[http_blog.csdn.net_zhangphil_article_details_65936066]: http://blog.csdn.net/zhangphil/article/details/65936066