Android简明开发教程十五：RadioButton 多边形及路径绘制

这个例子是绘制多边形，多义形和路径，采用单选钮RadioButton来选择Polys 和Path示例:

UI 设计为 上部分用来显示绘图内容，下部分为两个单选按钮 Polys ，Path。这样layout就和main.xml 不一样，main.xml只含一个com.pstreets.graphics2d.GuidebeeGraphics2DView。因此需在res/layout下新建一个polys.xml：

<?xml version=”1.0″ encoding=”utf-8″?>
<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
    android:orientation=”vertical”
    android:background=”@drawable/white”
 android:layout_width=”fill_parent”
 android:layout_height=”fill_parent”>
    <com.pstreets.graphics2d.GuidebeeGraphics2DView
     android:id=”@+id/graphics2dview”
     android:layout_weight=”1″
     android:layout_width=”fill_parent”
     android:layout_height=”wrap_content”/>
 <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
  android:layout_width=”wrap_content” android:layout_height=”wrap_content”
  android:orientation=”horizontal”
  
  >
  <RadioGroup
     android:layout_width=”wrap_content”
     android:orientation=”horizontal”
     android:textSize=”20dp”
     android:layout_height=”wrap_content”>
   <RadioButton android:text=”Polys”
       android:id=”@+id/radioPolys”
    android:layout_width=”wrap_content”
    android:textColor=”@color/black”
    android:checked=”true”
    android:layout_height=”wrap_content”>
   </RadioButton>
   <RadioButton android:text=”Path”
        android:id=”@+id/radioPath”
    android:layout_width=”wrap_content”
    android:textColor=”@color/black”
    android:layout_height=”wrap_content”>
   </RadioButton>
  </RadioGroup>
 </LinearLayout>

</LinearLayout>

RadioButton 需包含在RadioGroup中做为一个分组，这里将Polys 设为选中。

定义好Layout资源后，修改 Path.java

private RadioButton radioPoly;
private RadioButton radioPath;

public void onCreate(Bundle savedInstanceState) {
 super .onCreate(savedInstanceState);
 setContentView(R.layout.polys);
 graphic2dView
  = (GuidebeeGraphics2DView)
    findViewById(R.id.graphics2dview);
 radioPath = (RadioButton) findViewById(R.id.radioPath);
 radioPoly = (RadioButton) findViewById(R.id.radioPolys);
 radioPath.setOnClickListener( this );
 radioPoly.setOnClickListener( this );
}

应为需要处理按键消息，所以定义了两个RadioButton对象，可以通过findViewById获取实例。因为两个RadioButton这里采用同样的处理方法，可以让Path实现OnClickListener ，即：public class Path extends Graphics2DActivity   implements OnClickListener。完整代码如下：

public class Path extends Graphics2DActivity
   implements OnClickListener {

    private RadioButton radioPoly;
    private RadioButton radioPath;

    public void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout.polys);
        graphic2dView
         = (GuidebeeGraphics2DView)
           findViewById(R.id.graphics2dview);
        radioPath = (RadioButton) findViewById(R.id.radioPath);
        radioPoly = (RadioButton) findViewById(R.id.radioPolys);
        radioPath.setOnClickListener( this );
        radioPoly.setOnClickListener( this );
    }

    @Override
    protected void drawImage() {
        if (radioPoly.isChecked()) {
            drawPolys();
        } else {
            drawPaths();
        }
        graphic2dView.refreshCanvas();

    }

    @Override
    public void onClick(View view) {
        drawImage();
    }

    private void drawPaths() {
        AffineTransform mat1;

        // The path.
        com.mapdigit.drawing.geometry.Path path;

        // Colors
        Color redColor = new Color( 0x96ff0000 , true );
        Color greenColor = new Color( 0xff00ff00 );
        Color blueColor = new Color( 0x750000ff , true );

        String pathdata
           = "M 60 20 Q -40 70 60 120 Q 160 70 60 20 z" ;
        mat1 = new AffineTransform();
        mat1.translate( 30 , 40 );
        mat1.rotate(- 30 * Math.PI / 180.0 );
        path = com.mapdigit.drawing.geometry.Path.fromString(pathdata);
        // Clear the canvas with white color.
        graphics2D.clear(Color.WHITE);

        graphics2D.setAffineTransform( new AffineTransform());
        SolidBrush brush = new SolidBrush(greenColor);
        graphics2D.fill(brush, path);
        graphics2D.setAffineTransform(mat1);

        brush = new SolidBrush(blueColor);
        com.mapdigit.drawing.Pen pen
           = new com.mapdigit.drawing.Pen(redColor, 5 );
        graphics2D.setPenAndBrush(pen, brush);
        graphics2D.draw( null , path);
        graphics2D.fill( null , path);

    }

    private void drawPolys() {
        AffineTransform mat1;

        // Colors
        Color redColor = new Color( 0x96ff0000 , true );
        Color greenColor = new Color( 0xff00ff00 );
        Color blueColor = new Color( 0x750000ff , true );

        Polyline polyline;
        Polygon polygon;
        Polygon polygon1;

        String pointsdata1
        = "59,45,95,63,108,105,82,139,39,140,11,107,19,65" ;
        mat1 = new AffineTransform();
        mat1.translate( 30 , 40 );
        mat1.rotate(- 30 * Math.PI / 180.0 );
        polyline = new Polyline();
        polygon = new Polygon();
        polygon1 = new Polygon();
        Point[] points = Point.fromString(pointsdata1);
        for ( int i = 0 ; i < points.length; i++) {
            polyline.addPoint(points[i].x, points[i].y);
            polygon.addPoint(points[i].x, points[i].y);
            polygon1.addPoint(points[i].x, points[i].y);
        }
        // Clear the canvas with white color.
        graphics2D.clear(Color.WHITE);

        graphics2D.setAffineTransform( new AffineTransform());
        SolidBrush brush = new SolidBrush(greenColor);
        graphics2D.fillPolygon(brush, polygon);
        graphics2D.setAffineTransform(mat1);

        brush = new SolidBrush(blueColor);
        com.mapdigit.drawing.Pen pen
           = new com.mapdigit.drawing.Pen(redColor, 5 );
        graphics2D.setPenAndBrush(pen, brush);
        graphics2D.fillPolygon( null , polygon1);
        graphics2D.drawPolyline( null , polyline);

    }

}