android studio 如何画线

经过鄙人两年的大学生活，要画线的课程设计或实验遇到过两次，前些天课程设计选择的安卓搞界面，遇到过很多困难，还要几天之内搞定，界面好坑，就想写一下。

Canvas画布

必须的，之前我有想过用一个ImageView代替然后给这个控件加一张斜线图片，最终，浪费了我两天时间。

这个画布我不想多说什么，必须用RelativeLayout布局！！！！！！！！直接上代码：

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class NewView extends View {

    private float startX;
    private float startY;
    private float stopX;
    private float stopY;

    private float startXX;
    private float startYY;
    private float stopXX;
    private float stopYY;

    private int distance = 0;

    private String connetRouter;
    private String connectNet;

    private Bitmap bitmp ;

    public NewView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public NewView(luyouView luyouview, float startX, float startY, float stopX, float stopY) {
        super(luyouview);
        this.startX = startX;
        this.startY = startY;
        this.stopX = stopX;
        this.stopY = stopY;
        bitmp =Bitmap.createBitmap(500,500, Bitmap.Config.ARGB_8888);
    }

    // 当Android系统需要绘制一个View对象时，就会嗲用该对象的onDraw
    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawColor(Color.parseColor("#00FFFFFF"));
        Paint paint = new Paint();
        paint.setColor(Color.BLACK);
        if (startX < stopX) {
            if (startY > stopY){
                canvas.drawLine(0, startY-stopY, stopX-startX,0, paint);
            }
            if (startY < stopY){
                canvas.drawLine(0, 0, stopX - startX,stopY-startY, paint);
            }
        }
        if(startX > stopX) {
            if (startY > stopY) {
                canvas.drawLine(startX - stopX, startY - stopY, 0,0, paint);
            }
            if (startY < stopY) {
                canvas.drawLine(0, stopY - startY, startX - stopX,0, paint);
            }
        }
        super.onDraw(canvas);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        //设置宽高
        setMeasuredDimension((int)Math.abs(stopX-startX), (int)Math.abs(stopY-startY));
    }

    public void setStartXX(float startXX) {
        this.startXX = startXX;
    }

    public void setStartYY(float startYY) {
        this.startYY = startYY;
    }

    public void setStopXX(float stopXX) {
        this.stopXX = stopXX;
    }

    public void setStopYY(float stopYY) {
        this.stopYY = stopYY;
    }

    public void setDistance(int distance) {
        this.distance = distance;
    }

    public void setConnetRouter(String connetRouter) {
        this.connetRouter = connetRouter;
    }

    public void setConnectNet(String connectNet) {
        this.connectNet = connectNet;
    }

    public float getStartXX() {
        return startXX;
    }

    public float getStartYY() {
        return startYY;
    }

    public float getStopXX() {
        return stopXX;
    }

    public float getStopYY() {
        return stopYY;
    }

    public int getDistance() {
        return distance;
    }

    public String getConnetRouter() {
        return connetRouter;
    }

    public String getConnectNet() {
        return connectNet;
    }
}

这个类中用来画线的就只有其中的onDraw函数了，其它的get和set都是我的课程设计需要的东西。这个类的主要作用就是：画线，并且缩小view至其与线条在xy轴上的投影长宽相等的位置，但是，这个线条画出来之后，View的位置在左上角。

 

主程序对其的调用：

NewView newView = new NewView(luyouView.this, startX, startY, stopX, stopY);
relativeLayout.addView(newView);

主程序名字是luyouView，替换一下就行了，至于startX等等，就是另一段代码了，那块代码关系甚大，附上去你们肯定运行不了。这里的startX、startY、stopX、stopY就是画线的时候监控的手指起点和终点的x、y的坐标。最后你们移动一下view就行了。

 

移动View的代码：

        RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) 
        newView.getLayoutParams();
        params.height = newView.getHeight();
        params.width = newView.getWidth();

        if (startX < stopX) {
            if (startY >stopY){
                params.setMargins((int) startX,(int) stopY, (int)stopX, (int) startY);
            }
            if (startY < stopY){
                params.setMargins((int) startX, (int) startY, (int) stopX, (int) stopY);
            }
        }
        if(startX > stopX) {
            if (startY > stopY) {
                params.setMargins((int) stopX, (int) stopY, (int) startX, (int) startY);
            }
            if (startY < stopY) {
                params.setMargins((int) stopX, (int) startY, (int)startX, (int) stopY);
            }
        }
        newView.setLayoutParams(params);
        newView.setId(newViewOnlyId);
        newView.setStartXX(startX);
        newView.setStartYY(startY);
        newView.setStopXX(stopX);
        newView.setStopYY(stopY);
        newViewOnlyId++;
        if (connectInformation.get(0)[2] == 0)
            newView.setConnectNet(listNetButton.get(connectInformation.get(0)[0]).getText().toString());
        if (connectInformation.get(0)[2] == 1)
            newView.setConnetRouter(listRouterButton.get(connectInformation.get(0)[0]).getText().toString());
        if (connectInformation.get(1)[2] == 0)
            newView.setConnectNet(listNetButton.get(connectInformation.get(1)[0]).getText().toString());
        if (connectInformation.get(1)[2] == 1)
            newView.setConnetRouter(listRouterButton.get(connectInformation.get(1)[0]).getText().toString());
        connectInformation = new ArrayList<>();
        for (int i = 0; i < routers.size(); i++) {
            if (routers.get(i).getRouterName().equals(newView.getConnetRouter())){
                ArrayList connectNets = routers.get(i).getConnectNets();
                connectNets.add(newView.getConnectNet());
                routers.get(i).setConnectNets(connectNets);
                setRouters(i);
                break;
            }
        }

        listNewView.add(newView);
        if (((startX > stopX) && (startY > stopY)) || ((startX < stopX) && (startY < stopY))) {
            new PathInfo.Builder(new TopLeftAndButtomRight(), newView)
                    .setApplyFlag(APPLY_FLAG_DRAW_AND_TOUCH)
                    .setClipType(CLIP_TYPE_IN)
                    .create()
                    .apply();
        }else {
            new PathInfo.Builder(new ButtomLeftAndTopRight(), newView)
                    .setApplyFlag(APPLY_FLAG_DRAW_AND_TOUCH)
                    .setClipType(CLIP_TYPE_IN)
                    .create()
                    .apply();
        }
        // setContentView(newView);     //狗屁的setContentView，浪费我这么多时间

listNewView就是NewView的变长数组，最后的那段if else代码引用了别人写的控件切割布局，链接

这作用呢，当然是把长方形的View切割成我想要的形状。