Android自定义View实现多片叶子旋转滑动（五）

上一篇《Android 自定义View(四) 叶子飘动+旋转效果》实现了单片叶子的滑动及旋转，下面实现多片叶子的滑动旋转功能

实现思路比较简单，就是添加一个叶子Leaf类，储存每片叶子的信息，

然后随机产生叶子的坐标及旋转角度，最后实时获取每片叶子信息，添加到画布中

1、Leaf.java 叶子类

private class Leaf {
// 叶子的坐标
float x, y;
// 旋转角度
int rotateAngle;
// 起始时间(ms)
long startTime;
}

2、初始化每片叶子的信息，然后保存到list中

//使叶子初始时间有间隔
int addTime;
private Leaf getLeaf() {
Random random = new Random();
Leaf leaf = new Leaf();
//随机初始化叶子初始角度
leaf.rotateAngle = random.nextInt(360);
//随机初始化叶子启动时间
addTime += random.nextInt((int) (cycleTime));
leaf.startTime = System.currentTimeMillis() + cycleTime + addTime;
return leaf;
}
private List<Leaf> getLeafs(int leafSize) {
List<Leaf> list = new LinkedList<Leaf>();
for (int i=0; i<leafSize; i++) {
list.add(getLeaf());
}
return list;
}

3、接下去就是改写getLocation()及getRotate()方法，使其返回每片叶子的坐标及旋转角度

//获取每片叶子在XY轴上的滑动值
private void getLocation(Leaf leaf) {
float betweenTime = leaf.startTime - System.currentTimeMillis();
//周期结束再加一个cycleTime
if(betweenTime < 0) {
leaf.startTime = System.currentTimeMillis() + cycleTime + new Random().nextInt((int) (cycleTime));
betweenTime = cycleTime;
}
//通过时间差计算出叶子的坐标
float fraction = (float) betweenTime / cycleTime;
float x = (int)(width * fraction);
leaf.x = x;
float w = (float) ((float) 2 * Math.PI / width);
int y = (int) (18 * Math.sin(w * x)) + (height-mLeafHeight)/2;
leaf.y = y;
}
//获取每片叶子的旋转角度
private void getRotate(Leaf leaf) {
float scale = ((leaf.startTime - System.currentTimeMillis())%cycleTime)/ (float)cycleTime;
int rotate = (int)(scale * 360);
leaf.rotateAngle = rotate;
}

4、在onDraw()方法中，画出每片叶子

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//画叶子
int size = leafList.size();
for (int i=0; i<size; i++) {
Leaf leaf = leafList.get(i);
//获取叶子坐标
getLocation(leaf);
//获取叶子旋转角度
getRotate(leaf);
canvas.save();
Matrix matrix = new Matrix();
//设置滑动
matrix.postTranslate(leaf.x, leaf.y);
//设置旋转
matrix.postRotate(leaf.rotateAngle, leaf.x + mLeafWidth / 2, leaf.y + mLeafHeight / 2);
//添加叶子到画布
canvas.drawBitmap(mLeafBitmap, matrix, new Paint());
canvas.restore();
}
//调用onDraw()重复滑动
postInvalidate();
}

完整代码：

public class LeafView extends View {
private String TAG = "--------LeafView";
private Resources mResources;
//背景图、叶子
private Bitmap mLeafBitmap, bgBitmap;
//整个控件的宽度和高度
private int width, height;
private Paint bgPaint;
private RectF bgRect;
private Rect bgDestRect;
//存放叶子lsit
private List<Leaf> leafList;
//叶子的宽和高
private int mLeafWidth, mLeafHeight;
//叶子滑动一周的时间5秒
private final static long cycleTime = 5000;
//叶子数量
private final static int leafNumber = 5;
public LeafView(Context context, AttributeSet attrs) {
super(context, attrs);
mResources = getResources();
mLeafBitmap = ((BitmapDrawable) mResources.getDrawable(R.drawable.leaf, null)).getBitmap();
mLeafWidth = mLeafBitmap.getWidth();
mLeafHeight = mLeafBitmap.getHeight()
bgBitmap = ((BitmapDrawable) mResources.getDrawable(R.drawable.leaf_kuang, null)).getBitmap();
bgPaint = new Paint();
bgPaint.setColor(mResources.getColor(R.color.bg_color));
//获取所有叶子的信息，放入list
leafList = getLeafs(leafNumber);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
width = w;
height = h;
bgDestRect = new Rect(0, 0 , width, height);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
bgRect = new RectF(0, 0 , width, height);
//画背景颜色到画布
canvas.drawRect(bgRect, bgPaint);
//画背景图片到画布
canvas.drawBitmap(bgBitmap, null, bgDestRect, null);
//画叶子
int size = leafList.size();
for (int i=0; i<size; i++) {
Leaf leaf = leafList.get(i);
//获取叶子坐标
getLocation(leaf);
//获取叶子旋转角度
getRotate(leaf);
canvas.save();
Matrix matrix = new Matrix();
//设置滑动
matrix.postTranslate(leaf.x, leaf.y);
//设置旋转
matrix.postRotate(leaf.rotateAngle, leaf.x + mLeafWidth / 2, leaf.y + mLeafHeight / 2);
//添加叶子到画布
canvas.drawBitmap(mLeafBitmap, matrix, new Paint());
canvas.restore();
}
//调用onDraw()重复滑动
postInvalidate();
}
//获取每片叶子在XY轴上的滑动值
private void getLocation(Leaf leaf) {
float betweenTime = leaf.startTime - System.currentTimeMillis();
//周期结束再加一个cycleTime
if(betweenTime < 0) {
leaf.startTime = System.currentTimeMillis() + cycleTime + new Random().nextInt((int) (cycleTime));
betweenTime = cycleTime;
}
//通过时间差计算出叶子的坐标
float fraction = (float) betweenTime / cycleTime;
float x = (int)(width * fraction);
leaf.x = x;
float w = (float) ((float) 2 * Math.PI / width);
int y = (int) (18 * Math.sin(w * x)) + (height-mLeafHeight)/2;
leaf.y = y;
}
//获取每片叶子的旋转角度
private void getRotate(Leaf leaf) {
float scale = ((leaf.startTime - System.currentTimeMillis())%cycleTime)/ (float)cycleTime;
int rotate = (int)(scale * 360);
leaf.rotateAngle = rotate;
}private class Leaf {
// 叶子的坐标
float x, y;
// 旋转角度
int rotateAngle;
// 起始时间(ms)
long startTime;
}private List<Leaf> getLeafs(int leafSize) {
List<Leaf> list = new LinkedList<Leaf>();
for (int i=0; i<leafSize; i++) {
list.add(getLeaf());
}
return list;
}
//使叶子初始时间有间隔
int addTime;
private Leaf getLeaf() {
Random random = new Random();
Leaf leaf = new Leaf();
leaf.rotateAngle = random.nextInt(360);
addTime += random.nextInt((int) (cycleTime));
leaf.startTime = System.currentTimeMillis() + cycleTime + addTime;
return leaf;
}
}

这里还有很多瑕疵，比如叶子的滑动范围覆盖了边框等等

需要图片等信息的可以从下面的Github地址下载，不过原文比较复杂

参考 https://github.com/Ajian-studio/GALeafLoading

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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