作者:Anlia 地址:http://www.jianshu.com/p/f78f52c3c560 声明:本文是Anlia原创,已获其授权发布,未经原作者允许请勿转载
前言
前言:在上篇Android自定义View——从零开始实现书籍翻页效果(二)博客中,我们 补全了翻页效果以及增加了 取消翻页的动画,这期要教大家如何 向View填充内容
本篇只着重于思路和实现步骤,里面用到的一些知识原理不会非常细地拿来讲,如果有不清楚的api或方法可以在网上搜下相应的资料,肯定有大神讲得非常清楚的,我这就不献丑了。本着认真负责的精神我会把相关知识的博文链接也贴出来(其实就是懒不想写那么多哈哈),大家可以自行传送。为了照顾第一次阅读系列博客的小伙伴,本篇会出现一些在之前系列博客就讲过的内容,看过的童鞋自行跳过该段即可
国际惯例,先上效果图
目录
相关博文链接 Android中的裁剪中Region.Op参数的用法:http://blog.csdn.net/eyishion/article/details/53728913
A区域的内容,有可能包含文字,图案等各种元素,因此我们需要将这些统一绘制到一个Bitmap中,然后绘制到画布上,当然要记得裁剪这些内容,取其与A区域的交集,这样看起来才像将内容印在A区域中,修改BookPageView
public class BookPageView extends View { //省略部分代码...
private Paint textPaint;//绘制文字画笔
private void init(Context context, @Nullable AttributeSet attrs){ //省略部分代码...
textPaint = new Paint();
textPaint.setColor(Color.BLACK);
textPaint.setTextAlign(Paint.Align.CENTER);
textPaint.setSubpixelText(true);//设置自像素。如果该项为true,将有助于文本在LCD屏幕上的显示效果。
textPaint.setTextSize(30);
} @Override
protected void onDraw(Canvas canvas) { super.onDraw(canvas);
bitmap = Bitmap.createBitmap((int) viewWidth, (int) viewHeight, Bitmap.Config.ARGB_8888);
bitmapCanvas = new Canvas(bitmap); if(a.x==-1 && a.y==-1){// bitmapCanvas.drawPath(getPathDefault(),pathAPaint);
drawPathAContent(bitmapCanvas,getPathDefault(),pathAPaint);
}else { if(f.x==viewWidth && f.y==0){// bitmapCanvas.drawPath(getPathAFromTopRight(),pathAPaint);
drawPathAContent(bitmapCanvas,getPathAFromTopRight(),pathAPaint);
}else if(f.x==viewWidth && f.y==viewHeight){// bitmapCanvas.drawPath(getPathAFromLowerRight(),pathAPaint);
drawPathAContent(bitmapCanvas,getPathAFromLowerRight(),pathAPaint);
}
bitmapCanvas.drawPath(getPathC(),pathCPaint);
bitmapCanvas.drawPath(getPathB(),pathBPaint);
}
canvas.drawBitmap(bitmap,0,0,null);
} /**
* 绘制A区域内容
* @param canvas
* @param pathA
* @param pathPaint
*/
private void drawPathAContent(Canvas canvas, Path pathA, Paint pathPaint){
Bitmap contentBitmap = Bitmap.createBitmap(viewWidth, viewHeight, Bitmap.Config.RGB_565);
Canvas contentCanvas = new Canvas(contentBitmap); //下面开始绘制区域内的内容...
contentCanvas.drawPath(pathA,pathPaint);//绘制一个背景,用来区分各区域
contentCanvas.drawText("这是在A区域的内容...AAAA", viewWidth-260, viewHeight-100, textPaint); //结束绘制区域内的内容...
canvas.save();
canvas.clipPath(pathA, Region.Op.INTERSECT);//对绘制内容进行裁剪,取和A区域的交集
canvas.drawBitmap(contentBitmap, 0, 0, null);
canvas.restore();
}
}
效果如图
绘制B区域内容的原理和A区域一样,区别在于B区域内容取的是B区域不同于AC区域全集的部分,代码如下
public class BookPageView extends View {
private void init(Context context, @Nullable AttributeSet attrs){
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
bitmap = Bitmap.createBitmap((int) viewWidth, (int) viewHeight, Bitmap.Config.ARGB_8888);
bitmapCanvas = new Canvas(bitmap);
if(a.x==-1 && a.y==-1){
drawPathAContent(bitmapCanvas,getPathDefault(),pathAPaint);
}else {
if(f.x==viewWidth && f.y==0){
drawPathAContent(bitmapCanvas,getPathAFromTopRight(),pathAPaint);
bitmapCanvas.drawPath(getPathC(),pathCPaint);
drawPathBContent(bitmapCanvas,getPathAFromTopRight(),pathBPaint);
}else if(f.x==viewWidth && f.y==viewHeight){
drawPathAContent(bitmapCanvas,getPathAFromLowerRight(),pathAPaint);
bitmapCanvas.drawPath(getPathC(),pathCPaint);
drawPathBContent(bitmapCanvas,getPathAFromLowerRight(),pathBPaint);
}
}
}
private void drawPathBContent(Canvas canvas, Path pathA, Paint pathPaint){
Bitmap contentBitmap = Bitmap.createBitmap(viewWidth, viewHeight, Bitmap.Config.RGB_565);
Canvas contentCanvas = new Canvas(contentBitmap);
contentCanvas.drawPath(getPathB(),pathPaint);
contentCanvas.drawText("这是在B区域的内容...BBBB", viewWidth-260, viewHeight-100, textPaint);
canvas.save();
canvas.clipPath(pathA);
canvas.clipPath(getPathC(),Region.Op.UNION);
canvas.clipPath(getPathB(), Region.Op.REVERSE_DIFFERENCE);
canvas.drawBitmap(contentBitmap, 0, 0, null);
canvas.restore();
}
}
效果如图
相关博文链接: 安卓自定义View进阶-Matrix原理:http://blog.csdn.net/u013831257/article/details/52102081
C区域的内容填充是本期最复杂的一部分了。AB区域的内容都是直接绘制在相应区域即可,不需要做太多的处理,而我们看到的C区域内容,即当前页的背面其实是这样来的,如图(图出自大神AigeStudio的博客Android翻页效果原理实现之模拟扭曲)
那么如何得到该区域的内容呢?看下图及分析过程
至此,A区域内容翻转、旋转再位移得到C区域内容的原理分析完毕(我已经尽力去描述清楚了,希望大家能看懂和别嫌我讲得啰嗦_(:з」∠) _,至于数学知识都交回给老师的同学自己去网上查吧哈哈),我们根据之前的分析利用Matrix方面的知识编写算法,首先看下翻转矩阵
旋转矩阵,θ为要旋转的角度
我们按之前的分析先翻转后旋转,旋转角度为两倍角0计算,计算过程为
按照计算结果,开始修改我们的BookPageView
public class BookPageView extends View {
private Paint pathCContentPaint;
private void init(Context context, @Nullable AttributeSet attrs){
pathCContentPaint = new Paint();
pathCContentPaint.setColor(Color.YELLOW);
pathCContentPaint.setAntiAlias(true);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
bitmap = Bitmap.createBitmap((int) viewWidth, (int) viewHeight, Bitmap.Config.ARGB_8888);
bitmapCanvas = new Canvas(bitmap);
if(a.x==-1 && a.y==-1){
drawPathAContent(bitmapCanvas,getPathDefault(),pathAPaint);
}else {
if(f.x==viewWidth && f.y==0){
drawPathAContent(bitmapCanvas,getPathAFromTopRight(),pathAPaint);
drawPathCContent(bitmapCanvas,getPathAFromTopRight(),pathCContentPaint);
drawPathBContent(bitmapCanvas,getPathAFromTopRight(),pathBPaint);
}else if(f.x==viewWidth && f.y==viewHeight){
drawPathAContent(bitmapCanvas,getPathAFromLowerRight(),pathAPaint);
drawPathCContent(bitmapCanvas,getPathAFromLowerRight(),pathCContentPaint);
drawPathBContent(bitmapCanvas,getPathAFromLowerRight(),pathBPaint);
}
}
}
private void drawPathCContent(Canvas canvas, Path pathA, Paint pathPaint){
Bitmap contentBitmap = Bitmap.createBitmap(viewWidth, viewHeight, Bitmap.Config.RGB_565);
Canvas contentCanvas = new Canvas(contentBitmap);
contentCanvas.drawPath(getPathB(),pathPaint);
contentCanvas.drawText("这是在A区域的内容...AAAA", viewWidth-260, viewHeight-100, textPaint);
canvas.save();
canvas.clipPath(pathA);
canvas.clipPath(getPathC(), Region.Op.REVERSE_DIFFERENCE);
float eh = (float) Math.hypot(f.x - e.x,h.y - f.y);
float sin0 = (f.x - e.x) / eh;
float cos0 = (h.y - f.y) / eh;
float[] mMatrixArray = { 0, 0, 0, 0, 0, 0, 0, 0, 1.0f };
mMatrixArray[0] = -(1-2 * sin0 * sin0);
mMatrixArray[1] = 2 * sin0 * cos0;
mMatrixArray[3] = 2 * sin0 * cos0;
mMatrixArray[4] = 1 - 2 * sin0 * sin0;
Matrix mMatrix = new Matrix();
mMatrix.reset();
mMatrix.setValues(mMatrixArray);
mMatrix.preTranslate(-e.x, -e.y);
mMatrix.postTranslate(e.x, e.y);
canvas.drawBitmap(contentBitmap, mMatrix, null);
canvas.restore();
}
}
效果如图
还不够完美,可以观察到翻起的当前页背面还有一些空白的地方没有绘制内容,这是因为C区域的内容是通过当前页矩形翻转、旋转、位移后得到的,所以也是矩形,自然不能覆盖曲线的边缘区域。我们需要对这些边缘区域进行处理,根据背景的复杂度需要不同的处理方法,因为我们是纯色背景,所以处理起来会方便一些,这里只给出纯色背景的处理方案,其他背景图案大家自行扩展即可
public class BookPageView extends View {
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if(a.x==-1 && a.y==-1){
drawPathAContent(bitmapCanvas,getPathDefault(),pathAPaint);
}else {
if(f.x==viewWidth && f.y==0){
drawPathAContent(bitmapCanvas,getPathAFromTopRight(),pathAPaint);
bitmapCanvas.drawPath(getPathC(),pathCPaint);
drawPathCContent(bitmapCanvas,getPathAFromTopRight(),pathCContentPaint);
drawPathBContent(bitmapCanvas,getPathAFromTopRight(),pathBPaint);
}else if(f.x==viewWidth && f.y==viewHeight){
drawPathAContent(bitmapCanvas,getPathAFromLowerRight(),pathAPaint);
bitmapCanvas.drawPath(getPathC(),pathCPaint);
drawPathCContent(bitmapCanvas,getPathAFromLowerRight(),pathCContentPaint);
drawPathBContent(bitmapCanvas,getPathAFromLowerRight(),pathBPaint);
}
}
}
private void drawPathCContent(Canvas canvas, Path pathA, Paint pathPaint){canvas.save();
canvas.clipPath(pathA);
canvas.clipPath(getPathC(),Region.Op.UNION);
canvas.clipPath(getPathC(), Region.Op.INTERSECT);
}
}
效果如图
至此本篇教程到此结束,至于填充的内容如何自定义就留给大家自行扩展了,原理都是一样的。如果大家看了感觉还不错麻烦点个赞,你们的支持是我最大的动力~
源码:https://github.com/AnliaLee/BookPage,欢迎star
大家要是看到有错误的地方或者有啥好的建议,欢迎留言评论