android 实现代码

这里给出一个简单的 Android 实现代码示例，假设已知两个点为 (x1, y1) 和 (x2, y2)，矩形的左上角坐标为 (left, top)，右下角坐标为 (right, bottom)：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 已知两点和矩形边框
        int x1 = 100;
        int y1 = 200;
        int x2 = 300;
        int y2 = 400;
        int left = 150;
        int top = 250;
        int right = 350;
        int bottom = 450;

        // 计算矩形的四条边的方程
        int a1 = left;
        int b1 = top;
        int c1 = right;
        int d1 = top;
        int a2 = right;
        int b2 = top;
        int c2 = right;
        int d2 = bottom;
        int a3 = right;
        int b3 = bottom;
        int c3 = left;
        int d3 = bottom;
        int a4 = left;
        int b4 = bottom;
        int c4 = left;
        int d4 = top;

        // 计算两点之间的直线方程
        float k = (float) (y2 - y1) / (x2 - x1);
        float b = y1 - k * x1;

        // 计算两点直线与矩形四条边的交点
        float[] points = new float[8];
        points[0] = (b1 - b) / k;
        points[1] = b1;
        points[2] = c1;
        points[3] = k * c1 + b;
        points[4] = (d2 - b) / k;
        points[5] = d2;
        points[6] = a3;
        points[7] = k * a3 + b;

        // 判断交点是否在矩形内部
        List<Float> intersectPoints = new ArrayList<>();
        for (int i = 0; i < points.length; i += 2) {
            float x = points[i];
            float y = points[i + 1];
            if (x >= left && x <= right && y >= top && y <= bottom) {
                intersectPoints.add(x);
                intersectPoints.add(y);
            }
        }

        // 选择距离最近的交点
        float minDistance = Float.MAX_VALUE;
        float intersectX = 0;
        float intersectY = 0;
        for (int i = 0; i < intersectPoints.size(); i += 2) {
            float x = intersectPoints.get(i);
            float y = intersectPoints.get(i + 1);
            float distance = (x - x1) * (x - x1) + (y - y1) * (y - y1);
            if (distance < minDistance) {
                minDistance = distance;
                intersectX = x;
                intersectY = y;
            }
        }

        // 输出结果
        Log.d("MainActivity", "相交点坐标：(" + intersectX + ", " + intersectY + ")");
    }
}

这段代码先计算了矩形的四条边的方程，然后计算两点之间的直线方程，并分别求出该直线与矩形四条边的交点。接着，判断交点是否在矩形内部，并将符合条件的交点存入一个列表中。最后，从列表中选择距离最近的点作为相交点，并输出结果。