自定义view获取drawable图片

//activity

text_handler = (TextView) findViewById(R.id.text_handler);
SpreadView rview=(SpreadView)findViewById(R.id.spreadView);
rview.setCoreImage(R.drawable.headx);

//自定义view的方法

public class SpreadView extends View {

    /** 圆圈中心图片 */
    private Bitmap mBitmap;


    private Paint centerPaint; //中心圆paint
    private int radius = 100; //中心圆半径
    private Paint spreadPaint; //扩散圆paint
    private float centerX;//圆心x
    private float centerY;//圆心y
    private int distance = 5; //每次圆递增间距
    private int maxRadius = 80; //最大圆半径
    private int delayMilliseconds = 33;//扩散延迟间隔，越大扩散越慢
    private List<Integer> spreadRadius = new ArrayList<>();//扩散圆层级数，元素为扩散的距离
    private List<Integer> alphas = new ArrayList<>();//对应每层圆的透明度
    private int centerColor;

    public SpreadView(Context context) {
        this(context, null, 0);
    }

    public SpreadView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public SpreadView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SpreadView, defStyleAttr, 0);
        radius = a.getInt(R.styleable.SpreadView_spread_radius, radius);
        maxRadius = a.getInt(R.styleable.SpreadView_spread_max_radius, maxRadius);
        centerColor = a.getColor(R.styleable.SpreadView_spread_center_color, ContextCompat.getColor(context, R.color.colorAccent));
        int spreadColor = a.getColor(R.styleable.SpreadView_spread_spread_color, ContextCompat.getColor(context, R.color.colorAccent));
        distance = a.getInt(R.styleable.SpreadView_spread_distance, distance);

        a.recycle();

        centerPaint = new Paint();
        //centerPaint.setColor(centerColor);
        //centerPaint.setAntiAlias(true);
        //最开始不透明且扩散距离为0
        alphas.add(255);
        spreadRadius.add(0);
        spreadPaint = new Paint();
        spreadPaint.setAntiAlias(true);
        spreadPaint.setAlpha(255);
        spreadPaint.setColor(spreadColor);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        //圆心位置
        centerX = w / 2;
        centerY = h / 3;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        for (int i = 0; i < spreadRadius.size(); i++) {
            int alpha = alphas.get(i);
            spreadPaint.setAlpha(alpha);
            int width = spreadRadius.get(i);
            //绘制扩散的圆
            canvas.drawCircle(centerX, centerY, radius + width, spreadPaint);

            //每次扩散圆半径递增，圆透明度递减
            if (alpha > 0 && width < 300) {
                alpha = alpha - distance > 0 ? alpha - distance : 1;
                alphas.set(i, alpha);
                spreadRadius.set(i, width + distance);
            }
        }
        //当最外层扩散圆半径达到最大半径时添加新扩散圆
        if (spreadRadius.get(spreadRadius.size() - 1) > maxRadius) {
            spreadRadius.add(0);
            alphas.add(255);
        }
        //超过8个扩散圆，删除最先绘制的圆，即最外层的圆
        if (spreadRadius.size() >= 8) {
            alphas.remove(0);
            spreadRadius.remove(0);
        }
        //中间的圆   这地方加载图片
        canvas.drawCircle(centerX, centerY, radius, centerPaint);
        centerPaint.setAlpha(255);
        centerPaint.setColor(centerColor);
        //canvas.drawCircle(getWidth() / 2, getHeight() / 2, radius, centerPaint);

        if(mBitmap != null){
            canvas.drawBitmap(mBitmap, getWidth() / 2 - mBitmap.getWidth() / 2
                    , getHeight() / 3 - mBitmap.getHeight() / 3, centerPaint);
            Log.d("/////////centerX", String.valueOf(centerX));
            Log.d("/////////centerY", String.valueOf(centerY));
            Log.d("/////////getWidth()/2", String.valueOf(getWidth() / 2));
            Log.d("/////////getHeight()/3", String.valueOf(getHeight() / 3));
            Log.d("/////////mBitmap", String.valueOf(mBitmap));
            Log.d("//mBitmap.getWidth()/2", String.valueOf(mBitmap.getWidth() / 2));
            Log.d("//mBitmap.getHeight()/3", String.valueOf(mBitmap.getHeight() / 3));
        }
        //TODO 可以在中间圆绘制文字或者图片
        //延迟更新，达到扩散视觉差效果
        postInvalidateDelayed(delayMilliseconds);
    }
    /**
     * 设置中心圆图片
     */
    public void setCoreImage(int imageId){
        mBitmap = BitmapFactory.decodeResource(getResources(), imageId);
    }
}

<com.video.demo.SpreadView
    android:id="@+id/spreadView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:spread_center_color="#9326FF"
    app:spread_delay_milliseconds="35"
    app:spread_distance="5"
    app:spread_max_radius="50"
    app:spread_radius="50"
    app:spread_spread_color="#9326FF" />

//styles

<declare-styleable name="SpreadView">
    <!--中心圆颜色-->
    <attr name="spread_center_color" format="color" />
    <!--中心圆半径-->
    <attr name="spread_radius" format="integer" />
    <!--扩散圆颜色-->
    <attr name="spread_spread_color" format="color" />
    <!--扩散间距-->
    <attr name="spread_distance" format="integer" />
    <!--扩散最大半径-->
    <attr name="spread_max_radius" format="integer" />
    <!--扩散延迟间隔-->
    <attr name="spread_delay_milliseconds" format="integer" />
</declare-styleable>