3D版翻页公告效果

代码地址如下：
http://www.demodashi.com/demo/12830.html

前言:

在逛小程序蘑菇街的时候，看到一个2D版滚动的翻页公告效果。其实看到这个效果的时候，一点都不觉得稀奇，因为之前也见过类似的。效果如下:

这里因为学习了3D平面的旋转，因此我自己也撸出了一个3D版的翻页公告效果:

是不是一下子觉得有趣多了呢，那就赶紧和我去看下如何做出这种效果吧 。

使用:

• 布局:

<!--指定从下到上翻滚-->
<com.xiangcheng.marquee3dview.Marquee3DView
    android:id="@+id/marquee3DView"
    android:layout_width="wrap_content"
    android:layout_height="25dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:direction="D2U"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginTop="8dp"
    android:background="#FFC0CB"
    android:gravity="center"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="@+id/marquee3DView"
    app:layout_constraintStart_toStartOf="@+id/marquee3DView"
    app:layout_constraintTop_toBottomOf="@+id/marquee3DView">
    <!--从上到下翻滚-->
    <com.xiangcheng.marquee3dview.Marquee3DView
        android:id="@+id/marquee3DView2"
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:layout_marginStart="10dp"
        app:back_color="#00ffffff"
        app:direction="U2D"
        app:highlight_color="#FF6347"
        app:highlight_position="3"
        app:rotate_duration="1500"
        app:show_duration="1500" />
</LinearLayout>

• 属性:

<declare-styleable name="Marquee3DView">
    <!--指定旋转的方向-->
    <attr name="direction" format="enum">
        <!--从上到下-->
        <enum name="U2D" value="2" />
        <!--从下到上-->
        <enum name="D2U" value="1" />
    </attr>
    <!--高亮的item位置-->
    <attr name="highlight_position" format="integer" />
    <!--item的颜色-->
    <attr name="back_color" format="color" />
    <!--高亮的文字、下划线颜色-->
    <attr name="highlight_color" format="color" />
    <!--3D旋转的时间-->
    <attr name="rotate_duration" format="integer" />
    <!--停留显示的时间-->
    <attr name="show_duration" format="integer" />
    <!--右边文字的颜色-->
    <attr name="label_text_color" format="color" />
    <!--右边文字的大小-->
    <attr name="label_text_size" format="dimension" />
    <!--指定左边图片的半径-->
    <attr name="label_bitmap_radius" format="dimension" />
    <!--bitmap和text之间的间距-->
    <attr name="label_bitmap_text_offset" format="dimension" />
</declare-styleable>

• 代码:

/**
 * 设置显示的label
 * @param marqueeLabels
 */
public void setMarqueeLabels(List<String> marqueeLabels)

/**
 * 设置显示的bitmap
 * @param labelBitmap
 */
public void setLabelBitmap(List<Bitmap> labelBitmap)

/**
 * 点击监听
 * 
 */
setOnWhereItemClick(new Marquee3DView.OnWhereItemClick() {
    @Override
    public void onItemClick(int position) {
        //TODO
    }
});

• gradle:

compile 'com.xiangcheng:marquee3dlibs:1.0.1'

• maven:

<dependency>
  <groupId>com.xiangcheng</groupId>
  <artifactId>marquee3dlibs</artifactId>
  <version>1.0.1</version>
  <type>pom</type>
</dependency>

讲解:

• 初始化属性

private void initArgus(Context context, AttributeSet attrs) {
    TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.Marquee3DView);
    backColor = typedArray.getColor(R.styleable.Marquee3DView_back_color, Color.parseColor("#cccccc"));
    direction = typedArray.getInt(R.styleable.Marquee3DView_direction, D2U);
    highLightPosition = typedArray.getInt(R.styleable.Marquee3DView_highlight_position, highLightPosition);
    highLightColor = typedArray.getColor(R.styleable.Marquee3DView_highlight_color, Color.parseColor("#FF1493"));
    rotateDuration = typedArray.getInt(R.styleable.Marquee3DView_rotate_duration, rotateDuration);
    showDuration = typedArray.getInt(R.styleable.Marquee3DView_show_duration, showDuration);
    labelColor = typedArray.getColor(R.styleable.Marquee3DView_label_text_color, Color.parseColor("#778899"));
    labelTextSize = (int) typedArray.getDimension(R.styleable.Marquee3DView_label_text_size, sp2px(15));
    labelBitmapRadius = (int) typedArray.getDimension(R.styleable.Marquee3DView_label_bitmap_radius, dp2px(10));
    labelBitmapTextOffset = (int) typedArray.getDimension(R.styleable.Marquee3DView_label_bitmap_text_offset, dp2px(10));
}

• 初始化变量

private void initialize() {
    camera = new Camera();
    matrix = new Matrix();

    textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    textPaint.setTextSize(labelTextSize);
    textPaint.setColor(labelColor);

    currentPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    currentPaint.setTextSize(labelTextSize);
    currentPaint.setColor(labelColor);

    nextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    nextPaint.setTextSize(labelTextSize);
    nextPaint.setColor(labelColor);

    linePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    linePaint.setColor(highLightColor);
    linePaint.setStrokeWidth(dp2px(1));
    linePaint.setStyle(Paint.Style.FILL);

    highLightPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    highLightPaint.setTextSize(sp2px(15));
    highLightPaint.setColor(highLightColor);

    textRegion = new Region();

    mBitmapPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    mBitmapPaint.setColor(Color.WHITE);
    mBitmapPaint.setStrokeWidth(0);
}

• 初始化动画

private void initAnimation() {
    showItemRunable = new ShowItemRunable();
    //角度变化是0到90度的区间
    rotateAnimator = ValueAnimator.ofFloat(0, 90);
    rotateAnimator.setDuration(rotateDuration);
    rotateAnimator.setInterpolator(new LinearInterpolator());
    rotateAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            isRunning = true;
            //当前变化的角度变量，在绘制的时候使用
            changeRotate = (float) animation.getAnimatedValue();
            //计算当前的画笔的透明度(从255到0的过程)
            caculateCurrentPaint(changeRotate);
            //计算下一个item的画笔透明度(从0到255的过程)
            caculateNextPaint(changeRotate);
            //从0到height的一个过程，这里因为旋转的时候，同时还要进行平移
            translateY = height * animation.getAnimatedFraction();
            invalidate();
        }
    });
    //处理旋转结束后，停留一会显示
    rotateAnimator.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            super.onAnimationEnd(animation);
            isRunning = false;
            postDelayed(showItemRunable, showDuration);
        }
    });
    //刚进来的时候，在第一个item上进行停留
    startRunable = new StartRunable();
    postDelayed(startRunable, showDuration);
}

//停留显示完的操作
private class ShowItemRunable implements Runnable {
    @Override
    public void run() {
        currentItem++;
        if (currentItem >= marqueeLabels.size()) {
            currentItem = 0;
        }
        rotateAnimator.start();
    }
}

//刚进来时第一个item显示完后的操作
private class StartRunable implements Runnable {
    @Override
    public void run() {
        hasStart = true;
        rotateAnimator.start();
    }
}

//当前画笔透明度的改变(255——>0)
private void caculateCurrentPaint(float rotateAngle) {
    float percent = rotateAngle / 90;
    int alpha = (int) (255 - percent * 255);
    currentPaint.setAlpha(alpha);
}

//下一个item的画笔透明度的改变(0——>255)
private void caculateNextPaint(float rotateAngle) {
    float percent = rotateAngle / 90;
    int alpha = (int) (percent * 255);
    nextPaint.setAlpha(alpha);
}

上面动画部分，其实你要关心的就是两个变量:changeRotate(0——>90度变化)、translateY(0——>height变化)

• 绘制

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (marqueeLabels == null || marqueeLabels.size() <= 0) {
        return;
    }
    drawCurrentItem(canvas);
    drawNextItem(canvas);
}

private void drawCurrentItem(Canvas canvas) {
    canvas.save();
    camera.save();
    if (direction == D2U) {
        //当前的item从下到上转动，逆时针旋转，角度是增大的过程
        camera.rotateX(changeRotate);
    } else {
        //从上到下旋转，顺时针旋转，角度是负角
        camera.rotateX(-changeRotate);
    }
    camera.getMatrix(matrix);
    camera.restore();
    if (direction == D2U) {
        将旋转中心至为下面一条边的中点上
        matrix.preTranslate(-width / 2, -height);
        //这里由于当前的item是往上转动的，下面的一条边最后是在0的位置了
        matrix.postTranslate(width / 2, height - translateY);
    } else {
        //这里如果是往下转动时，旋转中心就是上面一条边的中点了
        matrix.preTranslate(-width / 2, 0);
        //往下转动时，上面的边是不断地往下移动的，因此y轴是增大的
        matrix.postTranslate(width / 2, translateY);
    }
    //创建绘制的内容
    textBitmap = createChild(currentItem, false);
    canvas.drawBitmap(textBitmap, matrix, null);
    canvas.restore();
}

//这里用到了隔离绘制，将最后要画的东西都放到了bitmap上
private Bitmap createChild(int position, boolean isNext) {
    Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    canvas.drawColor(backColor);
    if (labelBitmap != null && labelBitmap.size() > 0) {
        //绘制bitmap
        drawLabelBitmap(canvas, position);
    }
    Paint.FontMetrics fontMetrics = textPaint.getFontMetrics();
    float allHeight = fontMetrics.descent - fontMetrics.ascent;
    float textWidth = textPaint.measureText(marqueeLabels.get(position));
    Rect rect = new Rect();
    rect.left = (int) labelTextStart;
    rect.right = (int) (labelTextStart + textWidth);
    rect.top = (int) (height / 2 - allHeight / 2);
    rect.bottom = (int) (height / 2 + allHeight / 2);
    textRegion.set(rect);
    //这里分是不是绘制下一个item
    if (isNext) {
        //如果是高亮的item，需要绘制下划线，以及改为高亮画笔
        if (highLightPosition == position) {
            caculateHighLightPaint(changeRotate, true);
            canvas.drawText(marqueeLabels.get(position), labelTextStart, height / 2 - allHeight / 2 - fontMetrics.ascent, highLightPaint);
            canvas.drawLine(labelTextStart, (float) (height * 1.0 / 2 + allHeight / 2),
                    labelTextStart + textWidth, (float) (height * 1.0 / 2 + allHeight / 2), linePaint);
        } else {
            canvas.drawText(marqueeLabels.get(position), labelTextStart, height / 2 - allHeight / 2 - fontMetrics.ascent, nextPaint);
        }
    } else {
        if (highLightPosition == position) {
            caculateHighLightPaint(changeRotate, false);
            canvas.drawText(marqueeLabels.get(position), labelTextStart, height / 2 - allHeight / 2 - fontMetrics.ascent, highLightPaint);
            canvas.drawLine(labelTextStart, (float) (height * 1.0 / 2 + allHeight / 2),
                    labelTextStart + textWidth, (float) (height * 1.0 / 2 + allHeight / 2), linePaint);
        } else {
            canvas.drawText(marqueeLabels.get(position), labelTextStart, height / 2 - allHeight / 2 - fontMetrics.ascent, currentPaint);
        }
    }
    return bitmap;
}

//绘制左边的bitmap
private void drawLabelBitmap(Canvas canvas, int position) {
    int layer = canvas.saveLayer(0, 0, width, height, null, Canvas.ALL_SAVE_FLAG);
    //先画圆，dst层
    canvas.drawCircle(labelBitmapRadius, height / 2, labelBitmapRadius, mBitmapPaint);
    //该mode下取两部分的交集部分
    mBitmapPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    //src层
    canvas.drawBitmap(labelBitmap.get(position), 0, height / 2 - labelBitmapRadius, mBitmapPaint);
    mBitmapPaint.setXfermode(null);
    canvas.restoreToCount(layer);
    labelTextStart = labelBitmapRadius * 2 + labelBitmapTextOffset;
}

//计算高亮的画笔的透明度,跟普通的画笔一样的算法
private void caculateHighLightPaint(float rotate, boolean isNext) {
    if (isNext) {
        float percent = rotate / 90;
        int alpha = (int) (percent * 255);
        highLightPaint.setAlpha(alpha);
        linePaint.setAlpha(alpha);
    } else {
        float percent = rotate / 90;
        int alpha = (int) (255 - percent * 255);
        highLightPaint.setAlpha(alpha);
        linePaint.setAlpha(alpha);
    }
}

private void drawNextItem(Canvas canvas) {
    caculateNextItem();
    canvas.save();
    camera.save();
    if (direction == D2U) {
        //从下到上时，另外一个面初始位置是-90度，最后趋于0度位置
        camera.rotateX(-90 + changeRotate);
    } else {
        //从上到下是90度到0度的过程
        camera.rotateX(90 - changeRotate);
    }
    camera.getMatrix(matrix);
    camera.restore();
    if (direction == D2U) {
        //从下到上，旋转点是上面一条边的中点
        matrix.preTranslate(-width / 2, 0);
        //初始位置是height，最后到了0的位置
        matrix.postTranslate(width / 2, height + (-translateY));
    } else {
        //从上到下，旋转点是下面一条边的中点
        matrix.preTranslate(-width / 2, -height);
        //初始位置是0，最后到了height位置
        matrix.postTranslate(width / 2, translateY);
    }
    textBitmap = createChild(nextItem, true);
    canvas.drawBitmap(textBitmap, matrix, null);
    canvas.restore();
}

这里给出了两种情况旋转前、旋转后的示意图，上面的平行四边形都是一个平面，可以想象下。

其实讲解到这就基本没什么了，再就是一些细节性的代码了。如果有什么不明白的地方，可以互相交流。

总结:

(一):初始化一些需要的变量
(二):初始化动画变量
(三):绘制两个翻转的平面

项目文件目录截图:

项目目录结构

3D版翻页公告效果

代码地址如下：
http://www.demodashi.com/demo/12830.html

注：本文著作权归作者，由demo大师代发，拒绝转载，转载需要作者授权