如何在画布上的android中绘制路径

Question

如何从数据库中存储的坐标在画布上的android中绘制路径

我曾尝试过fingerpaint，但是当我从数据库中取出坐标时，它从不同的位置绘制一条路径，如果我放了一个点来绘制它，则从最后一个绘图到此点绘制一条线。

以下是从数据库中读取坐标的代码....

public Cursor read() {
    Cursor cur = db.query("path_new", null, null, null, null, null, null);
    StringBuffer sbx_read, sby_read;

    cur.moveToFirst();
    float x1 = 0, y1 = 0;
    int pid_read = 1;
    int cur_pid;
    float mX1 = 0, mY1 = 0;
    do {

        sbx_read = new StringBuffer();
        sbx_read.append(cur.getString(0));
        sby_read = new StringBuffer();
        sby_read.append(cur.getString(1));
        cur.moveToNext();
        Log.d("X", sbx_read.toString());
        Log.d("Y", sby_read.toString());
        Path mPath1 = new Path();

        String[] sbx_read_array = sbx_read.toString().trim().split(",");
        String[] sby_read_array = sby_read.toString().trim().split(",");
        // mPath.moveTo(x1, y1);
        for (int i = 0; i < sbx_read_array.length; i++) {

            x1 = Float.parseFloat(sbx_read_array[i].toString());
            y1 = Float.parseFloat(sby_read_array[i].toString());

            mPath1.moveTo(x1, y1);
            // mPath.reset();

            // mX1 = x1;
            // mY1 = y1;

            float dx = Math.abs(x1 - mX1);
            float dy = Math.abs(y1 - mY1);
            if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
                mPath.reset();
                mPath1.quadTo(mX1, mY1, (x1 + mX1) / 2, (y1 + mY1) / 2);
                mX1 = x1;
                mY1 = y1;
                // Log.d("X1", String.valueOf(x1));
                // Log.d("mX1", String.valueOf(mX1));
                // Log.d("Y1", String.valueOf(y1));
                // Log.d("mY1", String.valueOf(mY1));

                mPath1.lineTo(mX1, mY1);
                mCanvas.drawPath(mPath1, mPaint);

            }
        }
    } while (cur.moveToNext());
    cur.close();
    return cur;
}

这里我从数据库到stringbuffer获取路径并将其转换为String数组，以便不同的路径可以存储在不同的记录中。

我的桌子是......

X-cordinatrs TEXT, Y-cordinatrs TEXT, Path_id INTEGER, PAGE_NO INTEGER

Answer 1

不确定这是否会有所帮助，但请您移动代码

在do之前实例化路径

Path mPath1 = new Path(); 
do{ }

并且

在while之后将drawPath方法移到外面：

while();
mCanvas.drawPath(mPath1, mPaint);

希望它有所帮助。您可能还想查看此链接

Answer 2

这是答案..

    do {

        sbx_read = new StringBuffer();
        sbx_read.append(cur.getString(0));
        sby_read = new StringBuffer();
        sby_read.append(cur.getString(1));

        String[] sbx_read_array = sbx_read.toString().trim().split(",");
        String[] sby_read_array = sby_read.toString().trim().split(",");

        for (int i = 0; i < sbx_read_array.length; i++) {

            x1 = Float.parseFloat(sbx_read_array[i].toString());
            y1 = Float.parseFloat(sby_read_array[i].toString());

            if (pid != cur.getInt(2)) {
                pid = cur.getInt(2);
                mPath1.reset();
                mPath1.moveTo(x1, y1);
            }
            mPath1.lineTo(x1, y1);
            mCanvas.drawPath(mPath1, mPaint);
        }
    } while (cur.moveToNext());
    cur.close();

这是代码的Do..While循环，只需用你的代码替换它。它会像你想要的那样工作........