利用path的lineto方法绘制一个三角形

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:text="绘制(path)"
android:onClick="onClick" />

<ImageView
android:id="@+id/imageView1"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_centerInParent="true"
android:background="#ff669900"
/>

</RelativeLayout>

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Path;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {

private ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageView=(ImageView) findViewById(R.id.imageView1);
}

public void onClick(View v){
//1.bitmap (背景对象)
Bitmap bitmap=
Bitmap.createBitmap(200,200,
Config.ARGB_8888);
//2.构建画布对象(Canvas)
Canvas c=new Canvas(bitmap);
//3.构建画笔对象(Paint)
Paint paint=new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
//4.执行绘制动作(绘制一个路径)
paint.setStyle(Style.STROKE);//必须要设置
paint.setStrokeWidth(2);
Path p=new Path();//通过此对象绘制一个轨迹
p.moveTo(50,50);//起始点
p.lineTo(50,10);//终止点
p.lineTo(100,50);//起始点(50,10),终止点
p.close();//形成闭环
c.drawPath(p, paint);
//5.显示绘制的对象
imageView.setImageBitmap(bitmap);

}

}