android 畫虛線

標籤：

 

 

用到的工具類：

DashPathEffect

android中對該類的說明如下： 

翻譯一下就是：

第一個參數intervals數組必須是偶數個元素(個數>=2)，偶數下標代表實線，奇數下標代表空白長度

第二個參數phase：向左位移量(位移量=phase mod (intervals數組各項之和), 即取餘運算)

注意：只有當Paint的style設定為STROKE或者FILL_AND_STROKE時才能繪製出虛線效果，如果Paint的style設定為FILL時是不會起作用的。

 

    /**     * The intervals array must contain an even number of entries (>=2), with     * the even indices specifying the "on" intervals, and the odd indices     * specifying the "off" intervals. phase is an offset into the intervals     * array (mod the sum of all of the intervals). The intervals array     * controls the length of the dashes. The paint‘s strokeWidth controls the     * thickness of the dashes.     * Note: this patheffect only affects drawing with the paint‘s style is set     * to STROKE or FILL_AND_STROKE. It is ignored if the drawing is done with     * style == FILL.     * @param intervals array of ON and OFF distances     * @param phase offset into the intervals array     */    public DashPathEffect(float intervals[], float phase) {        if (intervals.length < 2) {            throw new ArrayIndexOutOfBoundsException();        }        native_instance = nativeCreate(intervals, phase);    }

 

初始化paint, Path

private Paint mDottedLinePaint;private Path mDottedPath;// 虛線paintmDottedLinePaint = new Paint();mDottedLinePaint.setColor(getResources().getColor(R.color.horizontal_bar_chart_dot_line_color));mDottedLinePaint.setStyle(Style.STROKE);mDottedLinePaint.setStrokeWidth(2);PathEffect effects = new DashPathEffect(new float[]{ 10, 5}, 1);//意思是所畫虛線規則是先畫10個長度的實線，留下5個長度的空白mDottedLinePaint.setPathEffect(effects);mDottedPath = new Path();

 

畫虛線

canvas.drawPath(mDottedPath, mDottedLinePaint);

這裡需要注意，一定要用canvas的drawPath方法，如果用drawLine的話是畫不出效果的，原來在網上找的代碼就是用的drawLine，結果半天出不來效果

android 畫虛線