Android弹幕实现：基于B站弹幕开源系统（7）QQ、微信聊天气泡样式的弹幕

在附录文章得基础上，改进普通文本弹幕，实现一种特殊效果的文本弹幕，像QQ、微信一样的带有气泡背景的弹幕。实现的重点是在SpannedCacheStuffer。同时要准备若干需要衬在文本弹幕背景部分的.9.png图片。

上层Java代码：

package zhangfei.danmaku;

import android.content.res.Configuration;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextPaint;
import android.util.Log;
import android.view.View;

import com.github.lzyzsd.randomcolor.RandomColor;

import java.util.HashMap;

import master.flame.danmaku.controller.IDanmakuView;
import master.flame.danmaku.danmaku.model.BaseDanmaku;
import master.flame.danmaku.danmaku.model.DanmakuTimer;
import master.flame.danmaku.danmaku.model.IDanmakus;
import master.flame.danmaku.danmaku.model.IDisplayer;
import master.flame.danmaku.danmaku.model.android.DanmakuContext;
import master.flame.danmaku.danmaku.model.android.SpannedCacheStuffer;
import master.flame.danmaku.ui.widget.DanmakuView;

public class MainActivity extends AppCompatActivity {
    private DanmakuView mDanmakuView;
    private DanmakuContext mContext;
    private AcFunDanmakuParser mParser;

    private AppCompatActivity mActivity;

    private final String TAG = getClass().getSimpleName();

    private BackgroundCacheStuffer mBackgroundCacheStuffer = new BackgroundCacheStuffer();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mActivity = this;
        setContentView(R.layout.activity_main);

        mContext = DanmakuContext.create();
        mParser = new AcFunDanmakuParser();

        initDanmakuView();

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                addItems();
            }
        });
    }

    private void initDanmakuView() {
        // 设置最大显示行数
        HashMap<Integer, Integer> maxLinesPair = new HashMap<>();
        maxLinesPair.put(BaseDanmaku.TYPE_SCROLL_RL, 5); // 滚动弹幕最大显示5行
        // 设置是否禁止重叠
        HashMap<Integer, Boolean> overlappingEnablePair = new HashMap<Integer, Boolean>();
        overlappingEnablePair.put(BaseDanmaku.TYPE_SCROLL_RL, true);
        overlappingEnablePair.put(BaseDanmaku.TYPE_FIX_TOP, true);

        mDanmakuView = (DanmakuView) findViewById(R.id.sv_danmaku);

        mContext.setDanmakuStyle(IDisplayer.DANMAKU_STYLE_STROKEN, 10)
                .setDuplicateMergingEnabled(false)
                .setScrollSpeedFactor(1.2f)
                .setScaleTextSize(1.0f)
                .setCacheStuffer(mBackgroundCacheStuffer, null)
                // 绘制背景使用BackgroundCacheStuffer
                .setMaximumLines(maxLinesPair)
                .preventOverlapping(overlappingEnablePair).setDanmakuMargin(40);

        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) {

                }

                @Override
                public void prepared() {
                    mDanmakuView.start();
                }
            });

            mDanmakuView.setOnDanmakuClickListener(new IDanmakuView.OnDanmakuClickListener() {

                @Override
                public boolean onDanmakuClick(IDanmakus danmakus) {
                    BaseDanmaku latest = danmakus.last();
                    if (null != latest) {
                        return true;
                    }
                    return false;
                }

                @Override
                public boolean onDanmakuLongClick(IDanmakus danmakus) {
                    return false;
                }

                @Override
                public boolean onViewClick(IDanmakuView view) {
                    return false;
                }
            });

            mDanmakuView.prepare(mParser, mContext);
            // mDanmakuView.showFPS(true);
            mDanmakuView.enableDanmakuDrawingCache(true);
        }
    }

    private void addItems() {
        RandomColor randomColor = new RandomColor();

        int id = (int) (Math.random() * 10) % 3;

        int resId;
        switch (id) {
            case 0:
                resId = R.drawable.bg_01;
                break;

            case 1:
                resId = R.drawable.bg_02;
                break;

            case 2:
                resId = R.drawable.bg_03;
                break;

            default:
                resId = R.drawable.bg_01;
                break;
        }

        String s = "";
        int count = (int) (Math.random() * 100) % 10 + 1;
        for (int i = 0; i < count; i++) {
            s = s + i;
        }

        addDanmaKuTextWithBackgroundImage(resId, s, randomColor.randomColor(), false);
    }

    /**
     * 绘制背景(自定义弹幕样式)
     */
    private class BackgroundCacheStuffer extends SpannedCacheStuffer {
        @Override
        public void measure(BaseDanmaku danmaku, TextPaint paint, boolean fromWorkerThread) {
            danmaku.padding = 50; // 在背景绘制模式下增加padding
            super.measure(danmaku, paint, fromWorkerThread);
        }

        @Override
        public void drawBackground(BaseDanmaku danmaku, Canvas canvas, float left, float top) {
            Object object = danmaku.tag;
            if (object instanceof DanmakuTag) {
                DanmakuTag danmakuTag = (DanmakuTag) object;

                Drawable drawable = ContextCompat.getDrawable(mActivity, danmakuTag.bitmapResId);

                float height = danmaku.paintHeight;
                float width = danmaku.paintWidth;

                Rect rect = new Rect(0, 0, (int) width, (int) height);
                drawable.setBounds(rect);
                drawable.draw(canvas);
            }
        }

        @Override
        public void drawStroke(BaseDanmaku danmaku, String lineText, Canvas canvas, float left,
                float top, Paint paint) {
            // 禁用描边绘制
        }
    }

    private void addDanmaKuTextWithBackgroundImage(int bitmap_resId, String msg,
                                                   int textColor, boolean islive) {
        BaseDanmaku danmaku = mContext.mDanmakuFactory.createDanmaku(BaseDanmaku.TYPE_SCROLL_RL);
        if (danmaku == null) {
            Log.e(TAG, "BaseDanmaku空");
        }

        DanmakuTag danmakuTag = new DanmakuTag();
        danmakuTag.bitmapResId = bitmap_resId;

        danmaku.setTag(danmakuTag);

        danmaku.text = "    " + msg + "      ";
        // danmaku.padding = 5;
        danmaku.priority = 1; // 一定会显示, 一般用于本机发送的弹幕
        danmaku.isLive = islive;
        danmaku.setTime(mDanmakuView.getCurrentTime() + 1200);
        danmaku.textSize = 25f * (mParser.getDisplayer().getDensity() - 0.6f);
        danmaku.textColor = textColor;
        danmaku.textShadowColor = 0; // 重要：如果有图文混排，最好不要设置描边(设textShadowColor=0)，否则会进行两次复杂的绘制导致运行效率降低
        // danmaku.underlineColor = Color.GREEN;
        // danmaku.borderColor=new RandomColor().randomColor();

        mDanmakuView.addDanmaku(danmaku);
    }

    private class DanmakuTag {
        public int bitmapResId;
    }

    @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();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mDanmakuView != null) {
            // dont forget release!
            mDanmakuView.release();
            mDanmakuView = null;
        }
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        if (mDanmakuView != null) {
            // dont forget release!
            mDanmakuView.release();
            mDanmakuView = null;
        }
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {
            mDanmakuView.getConfig().setDanmakuMargin(20);
        } else if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
            mDanmakuView.getConfig().setDanmakuMargin(40);
        }
    }
}

代码运行结果：

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   
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   
3，《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》链接：http://blog.csdn.net/zhangphil/article/details/68485505  
4，《Android弹幕实现：基于B站弹幕开源系统（4）-重构》链接：http://blog.csdn.net/zhangphil/article/details/68947236  
5，《Android弹幕实现：基于B站弹幕开源系统（5）-抽象和复用》链接：http://blog.csdn.net/zhangphil/article/details/69400428 
6，《Android弹幕实现：基于B站弹幕开源系统（6）带用户头像且头像从网络加载》链接：http://blog.csdn.net/zhangphil/article/details/72778984