Android画布绘制矩形

Question

如何使用borderWidth = 3和borderColor = black绘制空矩形，并且矩形内的部分没有内容或颜色。 Canvas中使用哪个功能

void drawRect(float left, float top, float right, float bottom, Paint paint)

void drawRect(RectF rect, Paint paint)

void drawRect(Rect r, Paint paint)

谢谢。

我试试这个例子

Paint myPaint = new Paint();
myPaint.setColor(Color.rgb(0, 0, 0));
myPaint.setStrokeWidth(10);
c.drawRect(100, 100, 200, 200, myPaint);

它绘制矩形并用黑色填充它但我只想像这个图像一样“框架”：

Answer 1

试试paint.setStyle(Paint.Style.STROKE)？

Answer 2

假设“矩形内的部分没有内容颜色”意味着您希望矩形内有不同的填充;您需要在矩形内绘制一个矩形，然后使用笔触宽度0和所需的填充颜色。

例如：

draw view.Java

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

public class DrawView extends View {
    Paint paint = new Paint();

    public DrawView(Context context) {
        super(context);            
    }

    @Override
    public void onDraw(Canvas canvas) {
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(3);
        canvas.drawRect(30, 30, 80, 80, paint);
        paint.setStrokeWidth(0);
        paint.setColor(Color.CYAN);
        canvas.drawRect(33, 60, 77, 77, paint );
        paint.setColor(Color.YELLOW);
        canvas.drawRect(33, 33, 77, 60, paint );

    }

}

启动它的活动：

start draw.Java

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;

public class StartDraw extends Activity {
    DrawView drawView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        drawView = new DrawView(this);
        drawView.setBackgroundColor(Color.WHITE);
        setContentView(drawView);

    }
}

......会这样：

Answer 3

//white background
canvas.drawRGB(255, 255, 255);
//border's properties
paint.setColor(Color.BLACK);
paint.setStrokeWidth(0);        
paint.setStyle(Paint.Style.STROKE);         
canvas.drawRect(100, 100, 200, 200, paint);

Answer 4

创建一个新类MyView, Which extends View。覆盖onDraw(Canvas canvas)方法在Canvas上绘制矩形。

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

public class MyView extends View {

 Paint paint;
 Path path;

 public MyView(Context context) {
  super(context);
  init();
 }

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

 public MyView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  init();
 }

 private void init(){
  paint = new Paint();
  paint.setColor(Color.BLUE);
  paint.setStrokeWidth(10);
  paint.setStyle(Paint.Style.STROKE);

 }

 @Override
 protected void onDraw(Canvas canvas) {
  // TODO Auto-generated method stub
  super.onDraw(canvas);

  canvas.drawRect(30, 50, 200, 350, paint);
  canvas.drawRect(100, 100, 300, 400, paint);
  //drawRect(left, top, right, bottom, paint)

 }

}

然后使用我们的自定义View，MyView.Call将您的Java活动移动到setContentView()。

    public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(new MyView(this));
  }

有关详细信息，请访问此处

http://developer.android.com/reference/android/graphics/Canvas.html

Answer 5

paint.setStrokeWidth(3);

paint.setColor(BLACK);

你的任何一个drawRect应该工作。

Answer 6

不知道这是否为时已晚，但我解决这个问题的方法是绘制四个薄的矩形，这些矩形组成一个大边框。用一个矩形绘制边框似乎是可以撤消的，因为它们都是不透明的，所以你应该分别绘制边框的每个边缘。

Answer 7

代码很好，只是绘制的setStyle为STROKE

paint.setStyle(Paint.Style.STROKE);