/**
* Created by Kingfar on 2017/12/18.
* 仿网易云音乐留声机（唱片机）View
*/
public class GramophoneView extends View {
/**
* 尺寸计算设计说明：
* 1、唱片有两个主要尺寸：中间图片的半径、黑色圆环的宽度。
* 黑色圆环的宽度 = 图片半径的一半。
* 2、唱针分为“手臂”和“头”，手臂分两段，一段长的一段短的，头也是一段长的一段短的。
* 唱针四个部分的尺寸求和 = 唱片中间图片的半径+黑色圆环的宽度
* 唱针各部分长度 比例——长的手臂：短的手臂：长的头：短的头 = 8:4:2:1
* 3、唱片黑色圆环顶部到唱针顶端的距离 = 唱针长的手臂的长度。
*/
private int halfMeasureWidth;
// 绘制唱片相关变量
// 中间图片默认半径
private static final int DEFAULT_PICTURE_RADIUS = 400;
// 唱片旋转默认速度，其实是通过每次旋转叠加的角度来控制速度
private static final float DEFAULT_DISK_ROTATE_SPEED = 0.3f;
private int pictureRadius; // 中间图片的半径
private int ringWidth; // 黑色圆环宽度
private float diskRotateSpeed;// 唱片旋转速度
private Paint discPaint; // 唱片画笔
private Path clipPath; // 裁剪图片的路径
private Bitmap bitmap; // 图片
private Rect srcRect; // 图片被裁减范围
private Rect dstRect; // 图片被绘制范围
// 绘制唱针相关变量
private static final int PLAY_DEGREE = -15; // 播放状态时唱针的旋转角度
private static final int PAUSE_DEGREE = -45; // 暂停状态时唱针的旋转角度
private int smallCircleRadius = 20; // 唱针顶部小圆半径
private int bigCircleRadius; // 唱针顶部大圆半径
private int longArmLength; // 唱针手臂，较长那段的长度
private int shortArmLength; // 唱针手臂，较短那段的长度
private int longHeadLength; // 唱针的头，较长那段的长度
private int shortHeadLength; // 唱针的头，较短那段的长度
private Paint needlePaint; // 唱针画笔
// 状态控制相关变量
private boolean isPlaying; // 是否处于播放状态
private int needleDegreeCounter; // 唱针旋转角度计数器
private float diskDegreeCounter; // 唱片旋转角度计数器
public GramophoneView(Context context) {
this(context, null);
}
public GramophoneView(Context context, AttributeSet attrs) {
super(context, attrs);
// 读取xml文件属性
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.GramophoneView);
pictureRadius = (int)typedArray.getDimension(R.styleable.GramophoneView_picture_radius, DEFAULT_PICTURE_RADIUS);
diskRotateSpeed = typedArray.getFloat(R.styleable.GramophoneView_disk_rotate_speed, DEFAULT_DISK_ROTATE_SPEED);
Drawable drawable = typedArray.getDrawable(R.styleable.GramophoneView_src);
if(drawable == null){
bitmap = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.gramophone_view_default_picture);
} else{
bitmap = ((BitmapDrawable)drawable).getBitmap();
}
typedArray.recycle();
// 初始化唱片变量
ringWidth = pictureRadius>>1;
discPaint = new Paint();
discPaint.setColor(Color.BLACK);
discPaint.setStyle(Paint.Style.STROKE);
discPaint.setStrokeWidth(ringWidth);
srcRect = new Rect();
dstRect = new Rect();
setBitmapRect(srcRect, dstRect);
clipPath = new Path();
clipPath.addCircle(0, 0, pictureRadius, Path.Direction.CW);
diskDegreeCounter = 0;
// 初始化唱针变量
bigCircleRadius = smallCircleRadius<<1;
shortHeadLength = (pictureRadius + ringWidth)/15;
longHeadLength = shortHeadLength<<1;
shortArmLength = longHeadLength<<1;
longArmLength = shortArmLength<<1;
needlePaint = new Paint();
needleDegreeCounter = PAUSE_DEGREE;
}
/**
* 根据加载的图片资源尺寸和设置的唱片中间图片直径，
* 为canvas.drawBitmap()方法设置源Rect和目标Rect，
* 以宽度为例，假设图片资源宽度为width，唱片中间图片直径为diameter
* 如果width <= diameter，则截取宽度为整张图片宽度。
* 如果width > diameter，则截取宽度为图片资源横向中间长度为diameter的区域。
* 高度的截取方法与宽度相同。
* @param src 源矩形
* @param dst 目标矩形
*/
private void setBitmapRect(Rect src, Rect dst){
src.set(0, 0, bitmap.getWidth(), bitmap.getHeight());
dst.set(-pictureRadius, -pictureRadius, pictureRadius, pictureRadius);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
/**
* wrap_content属性下View的宽高设计：
* 宽度：等于唱片直径，即图片半径+圆环宽度求和再乘以2。
* 高度：等于唱片直径+唱针较长的手臂
*/
int width = (pictureRadius+ringWidth)*2;
int height = (pictureRadius+ringWidth)*2+longArmLength;
int measuredWidth = resolveSize(width, widthMeasureSpec);
int measuredHeight = resolveSize(height, heightMeasureSpec);
setMeasuredDimension(measuredWidth, measuredHeight);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
halfMeasureWidth = getMeasuredWidth()>>1;
drawDisk(canvas);
drawNeedle(canvas);
if(needleDegreeCounter > PAUSE_DEGREE){
invalidate();
}
}
// 绘制唱片（胶片）
private void drawDisk(Canvas canvas){
diskDegreeCounter = diskDegreeCounter%360+diskRotateSpeed;
drawDisk(canvas, diskDegreeCounter);
}
// 绘制旋转了制定角度的唱片
private void drawDisk(Canvas canvas, float degree){
// 绘制圆环，注意理解平移的圆心距离和圆环半径是怎么计算的
canvas.save();
canvas.translate(halfMeasureWidth, pictureRadius+ringWidth+longArmLength);
canvas.rotate(degree);
canvas.drawCircle(0, 0, pictureRadius+ringWidth/2, discPaint);
// 绘制图片
canvas.clipPath(clipPath);
canvas.drawBitmap(bitmap, srcRect, dstRect, discPaint);
canvas.restore();
}
// 绘制唱针
private void drawNeedle(Canvas canvas){
// 由于PLAY_DEGREE和PAUSE_DEGREE之间的差值是30，所以每次增/减值应当是30的约数即可
if(isPlaying){
if(needleDegreeCounter < PLAY_DEGREE){
needleDegreeCounter+=3;
}
} else {
if(needleDegreeCounter > PAUSE_DEGREE){
needleDegreeCounter-=3;
}
}
drawNeedle(canvas, needleDegreeCounter);
}
// 绘制旋转了指定角度的唱针
private void drawNeedle(Canvas canvas, int degree){
// 移动坐标到水平中点
canvas.save();
canvas.translate(halfMeasureWidth, 0);
// 绘制唱针手臂
needlePaint.setStrokeWidth(20);
needlePaint.setColor(Color.parseColor("#C0C0C0"));
// 绘制第一段臂
canvas.rotate(degree);
canvas.drawLine(0, 0, 0, longArmLength, needlePaint);
// 绘制第二段臂
canvas.translate(0, longArmLength);
canvas.rotate(-30);
canvas.drawLine(0, 0, 0, shortArmLength, needlePaint);
// 绘制唱针头
// 绘制第一段唱针头
canvas.translate(0, shortArmLength);
needlePaint.setStrokeWidth(40);
canvas.drawLine(0, 0, 0, longHeadLength, needlePaint);
// 绘制第二段唱针头
canvas.translate(0, longHeadLength);
needlePaint.setStrokeWidth(60);
canvas.drawLine(0, 0, 0, shortHeadLength, needlePaint);
canvas.restore();
// 两个重叠的圆形
canvas.save();
canvas.translate(halfMeasureWidth, 0);
needlePaint.setStyle(Paint.Style.FILL);
needlePaint.setColor(Color.parseColor("#C0C0C0"));
canvas.drawCircle(0, 0, bigCircleRadius, needlePaint);
needlePaint.setColor(Color.parseColor("#8A8A8A"));
canvas.drawCircle(0, 0, smallCircleRadius, needlePaint);
canvas.restore();
}
/**
* 设置是否处于播放状态
* @param isPlaying true:播放，false:暂停
*/
public void setPlaying(boolean isPlaying){
this.isPlaying = isPlaying;
invalidate();
}
/**
* 获取播放状态
* @return true:播放，false:暂停
*/
public boolean getPlaying(){
return isPlaying;
}
/**
* 获取图片半径
* @return 图片半径
*/
public int getPictureRadius() {
return pictureRadius;
}
/**
* 设置图片半径
* @param pictureRadius 图片半径
*/
public void setPictureRadius(int pictureRadius) {
this.pictureRadius = pictureRadius;
}
/**
* 获取唱片旋转速度
* @return 唱片旋转速度
*/
public float getDiskRotateSpeed() {
return diskRotateSpeed;
}
/**
* 设置唱片旋转速度
* @param diskRotateSpeed 旋转速度
*/
public void setDiskRotateSpeed(float diskRotateSpeed) {
this.diskRotateSpeed = diskRotateSpeed;
}
/**
* 设置图片资源id
* @param resId 图片资源id
*/
public void setPictureRes(int resId){
bitmap = BitmapFactory.decodeResource(getContext().getResources(), resId);
setBitmapRect(srcRect, dstRect);
invalidate();
}
}//main
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final GramophoneView gramophoneView = (GramophoneView)findViewById(R.id.gramophone_view);
final Button button = (Button)findViewById(R.id.btn_play_pause);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(gramophoneView.getPlaying()){
button.setText("点击播放");
}else{
button.setText("点击暂停");
}
gramophoneView.setPlaying(!gramophoneView.getPlaying());
}
});
}
}//在res/values目录下创建attrs.xml
//main的xml
