短跑路径效果使屏幕缓慢

Question

我正在尝试使用由点组成的同心圆来制作自定义视图.我附上了截图供参考.直到时间自定义视图只有同心圆它工作正常但是一旦我应用DashPathEffect它会使整个屏幕缓慢,当你试图打开或关闭导航抽屉时,这是很好观察.我已经附上了以下日志.以下是解释问题的视频链接 https://youtu.be/5Mgz4QhXaQI

自定义视图

public class ConcentricCircularView extends View {
    private static final String TAG = "ConcentricCircularView";
    private Paint paint;
    private Context context;

    public ConcentricCircularView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        paint = new Paint();
        paint.setColor(Color.WHITE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(Utils.dipToPixels(context,getResources().getDimension(R.dimen.d1)));
        paint.setStrokeCap(Paint.Cap.ROUND);
        paint.setAntiAlias(true);
        this.context=context;

    }

    int onDrawCounter = 0;
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Log.e(TAG, "Actual radius"+getWidth());
        int radius= (int) (getWidth()/3);
        int distanceBtwDots= (int) Utils.dipToPixels(context,getResources().getDimension(R.dimen.d10));
        Log.e(TAG, "Counter: "+onDrawCounter++);
        for (int i=0;i<10;i++){
            DashPathEffect dashPath = new DashPathEffect(new float[]{1,distanceBtwDots}, 0);
            paint.setPathEffect(dashPath);
//            Log.e(TAG, "Current radius "+radius);
            canvas.drawCircle(getWidth()/2, getHeight()/2,radius, paint);
            radius= (int) (radius+Utils.dipToPixels(context,getResources().getDimension(R.dimen.d15)));
            distanceBtwDots= (int) (distanceBtwDots+Utils.dipToPixels(context,getResources().getDimension(R.dimen.d1)));

        }


    }
}

从控制台记录

[![03-22 12:01:38.734 19919-19919/com.lief.smartwallet D/ViewRootImpl: ViewPostImeInputStage processPointer 0
03-22 12:01:38.834 19919-19919/com.lief.smartwallet D/ViewRootImpl: ViewPostImeInputStage processPointer 1
03-22 12:01:39.474 19919-19919/com.lief.smartwallet I/Choreographer: Skipped 34 frames!  The application may be doing too much work on its main thread.
03-22 12:01:43.184 19919-19919/com.lief.smartwallet I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@e65187c time:662629
03-22 12:01:47.559 19919-19919/com.lief.smartwallet D/ViewRootImpl: ViewPostImeInputStage processPointer 0
03-22 12:01:47.679 19919-19919/com.lief.smartwallet D/ViewRootImpl: ViewPostImeInputStage processPointer 1

Answer 1

你只需要保留一个boolean指示是否需要画一些东西。目前，您不必要在每次迭代中绘制完全相同的东西。

正如罗曼·盖伊（Romain Guy）在这里所说的：

一般来说，硬件层应该设置在绘制成本较高且内容不会经常更改的视图上。

public class ConcentricCircularView extends View {
    ...
    private boolean shouldDraw = true;
    ...

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (shouldDraw) {
            shouldDraw = false;
            setLayerType(View.LAYER_TYPE_HARDWARE, null);
            // draw your view here
        }
    }

    public void setShouldDraw(boolean shouldDraw) {
        this.shouldDraw = shouldDraw;
    }
}