Android自定义View——QQ音乐中圆形旋转碟子

QQ音乐中圆形旋转碟子


思路分析:

1、在onMeasure中测量整个View的宽和高后,设置宽高

2、获取我们res的图片资源后,在ondraw方法中进行绘制圆形图片

3、通过Handler发送Runnable在主线程中更新UI,达到旋转效果(如果只想做圆形头像的话,这步可以去掉)

4、在布局中使用我们的View


效果图:



贴出我们的变量信息:

    //view的宽和高
    int mHeight = 0;
    int mWidth = 0;
    //圆形图片
    Bitmap bitmap = null;
    //圆形图片的真实半径
    int radius = 0;
    //旋转动画的矩形
    Matrix matrix = new Matrix();
    //旋转动画的角度
    int degrees = 0;

步骤一:测量整个View的宽和高后,设置宽高

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //测量整个View的宽和高
        mWidth = measuredWidth(widthMeasureSpec);
        mHeight= measuredHeight(heightMeasureSpec);
        setMeasuredDimension(mWidth, mHeight);
    }

    private int measuredWidth(int widthMeasureSpec) {
        int Mode = MeasureSpec.getMode(widthMeasureSpec);
        int Size = MeasureSpec.getSize(widthMeasureSpec);
        if (Mode == MeasureSpec.EXACTLY) {
            mWidth = Size;
        } else {
            //由图片决定宽度
            int value = getPaddingLeft() + getPaddingRight() + bitmap.getWidth();
            if (Mode == MeasureSpec.AT_MOST) {
                //由图片和Padding决定宽度,但是不能超过View的宽
                mWidth = Math.min(value, Size);
            }
        }
        return mWidth;
    }

    private int measuredHeight(int heightMeasureSpec) {
        int Mode = MeasureSpec.getMode(heightMeasureSpec);
        int Size = MeasureSpec.getSize(heightMeasureSpec);
        if (Mode == MeasureSpec.EXACTLY) {
            mHeight = Size;
        } else {
            //由图片决定高度
            int value = getPaddingTop() + getPaddingBottom() + bitmap.getHeight();
            if (Mode == MeasureSpec.AT_MOST) {
                //由图片和Padding决定高度,但是不能超过View的高
                mHeight = Math.min(value, Size);
            }
        }
        return mHeight;
    }

步骤二:获取我们res的图片资源后,在ondraw方法中进行绘制圆形图片
        //获取res的图片资源
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.concat(matrix);
        //真实的半径必须是View的宽高最小值
        radius = Math.min(mWidth, mHeight);
        //如果图片本身宽高太大,进行相应的缩放
        bitmap = Bitmap.createScaledBitmap(bitmap, radius, radius, false);
        //画圆形图片
        canvas.drawBitmap(createCircleImage(bitmap, radius), 0, 0, null);
        matrix.reset();
    }

    private Bitmap createCircleImage(Bitmap source, int radius) {
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        Bitmap target = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888);
        //产生一个同样大小的画布
        Canvas canvas = new Canvas(target);
        //首先绘制圆形
        canvas.drawCircle(radius / 2, radius / 2, radius / 2, paint);
        //使用SRC_IN模式显示后画图的交集处
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        //绘制图片,从(0,0)画
        canvas.drawBitmap(source, 0, 0, paint);
        return target;
    }

步骤三:通过Handler发送Runnable在主线程中更新UI,达到旋转效果

        //开始旋转
        mHandler.post(runnable);
    //-----------旋转动画-----------
    Handler mHandler = new Handler();
    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            matrix.postRotate(degrees++, radius / 2, radius / 2);
            //重绘
            invalidate();
            mHandler.postDelayed(runnable, 50);
        }
    };

步骤四:在布局中使用我们的View

    <com.handsome.cycle.MyCycleView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

下面是整个类的源码

public class MyCycleView extends View {

    //view的宽和高
    int mHeight = 0;
    int mWidth = 0;
    //圆形图片
    Bitmap bitmap = null;
    //圆形图片的真实半径
    int radius = 0;
    //旋转动画的矩形
    Matrix matrix = new Matrix();
    //旋转动画的角度
    int degrees = 0;

    //-----------旋转动画-----------
    Handler mHandler = new Handler();
    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            matrix.postRotate(degrees++, radius / 2, radius / 2);
            //重绘
            invalidate();
            mHandler.postDelayed(runnable, 50);
        }
    };

    public MyCycleView(Context context) {
        super(context);
        initView();
    }

    public MyCycleView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView();
    }

    public MyCycleView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView();
    }

    public void initView() {
        //获取res的图片资源
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
        //开始旋转
        mHandler.post(runnable);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //测量整个View的宽和高
        mWidth = measuredWidth(widthMeasureSpec);
        mHeight = measuredHeight(heightMeasureSpec);
        setMeasuredDimension(mWidth, mHeight);
    }

    private int measuredWidth(int widthMeasureSpec) {
        int Mode = MeasureSpec.getMode(widthMeasureSpec);
        int Size = MeasureSpec.getSize(widthMeasureSpec);
        if (Mode == MeasureSpec.EXACTLY) {
            mWidth = Size;
        } else {
            //由图片决定宽度
            int value = getPaddingLeft() + getPaddingRight() + bitmap.getWidth();
            if (Mode == MeasureSpec.AT_MOST) {
                //由图片和Padding决定宽度,但是不能超过View的宽
                mWidth = Math.min(value, Size);
            }
        }
        return mWidth;
    }

    private int measuredHeight(int heightMeasureSpec) {
        int Mode = MeasureSpec.getMode(heightMeasureSpec);
        int Size = MeasureSpec.getSize(heightMeasureSpec);
        if (Mode == MeasureSpec.EXACTLY) {
            mHeight = Size;
        } else {
            //由图片决定高度
            int value = getPaddingTop() + getPaddingBottom() + bitmap.getHeight();
            if (Mode == MeasureSpec.AT_MOST) {
                //由图片和Padding决定高度,但是不能超过View的高
                mHeight = Math.min(value, Size);
            }
        }
        return mHeight;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.concat(matrix);
        //真实的半径必须是View的宽高最小值
        radius = Math.min(mWidth, mHeight);
        //如果图片本身宽高太大,进行相应的缩放
        bitmap = Bitmap.createScaledBitmap(bitmap, radius, radius, false);
        //画圆形图片
        canvas.drawBitmap(createCircleImage(bitmap, radius), 0, 0, null);
        matrix.reset();
    }

    private Bitmap createCircleImage(Bitmap source, int radius) {
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        Bitmap target = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888);
        //产生一个同样大小的画布
        Canvas canvas = new Canvas(target);
        //首先绘制圆形
        canvas.drawCircle(radius / 2, radius / 2, radius / 2, paint);
        //使用SRC_IN模式显示后画图的交集处
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        //绘制图片,从(0,0)画
        canvas.drawBitmap(source, 0, 0, paint);
        return target;
    }
}



你可能感兴趣的:(android,android,控件,自定义view,Studio,圆形图片)