android自定义view画图

Main方法
package wuhao.bwei.com.wuhao20171130;import android.graphics.Paint;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.widget.LinearLayout;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        init();    }    private void init() {        LinearLayout layout = (LinearLayout) findViewById(R.id.pa);        Pain pp = new Pain(this);        pp.setMinimumHeight(500);        pp.setMinimumWidth(300);        pp.invalidate();        layout.addView(pp);    }}
布局中导入Pain类




package wuhao.bwei.com.wuhao20171130;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.LinearGradient;import android.graphics.Paint;import android.graphics.Path;import android.graphics.RectF;import android.graphics.Shader;import android.os.Build;import android.support.annotation.Nullable;import android.support.annotation.RequiresApi;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;/** * Created by alienware on 2017/11/30. */public class Pain extends View{    float x = 100f;    float y = 100f;    public Pain(Context context) {        super(context);    }    public Pain(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);    }    public Pain(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)    public Pain(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {        super(context, attrs, defStyleAttr, defStyleRes);    }    protected  void onDraw(Canvas canvas){        super.onDraw(canvas);        Paint p = new Paint();        p.setColor(Color.RED);        canvas.drawText("画圆",20,20,p);        canvas.drawCircle(x,y,50,p);        p.setAntiAlias(true);//设置画笔的锯齿效果。true是去除锯齿效果        canvas.drawText("画线和弧形",10,60,p);        //颜色设置为黄色        p.setColor(Color.BLACK);        canvas.drawLine(120,80,200,80,p);//画线        canvas.drawLine(220,80,380,160,p);//斜线        p.setStyle(Paint.Style.STROKE);//设置空心        RectF oval1=new RectF(150,20,180,40);        canvas.drawArc(oval1, 180, 180, false, p);//小弧形        oval1.set(190, 20, 220, 40);        canvas.drawArc(oval1, 180, 180, false, p);//小弧形        oval1.set(160, 30, 210, 60);        canvas.drawArc(oval1, 0, 180, false, p);//        //画矩形        canvas.drawText("画矩形",10,80,p);        //设置颜色        p.setColor(Color.BLUE);        //设置样式：填满        p.setStyle(Paint.Style.FILL);        //canvas.drawRect(120,120,160,160,p);//正方形：左上右下        canvas.drawRect(60,90,160,200,p);//长方形        //画扇形和椭圆        canvas.drawText("画扇形和椭圆",15,300,p);        /*设置渐变色 正方形颜色改变*/        Shader mShader = new LinearGradient(0,0,100,100,new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW,Color.LTGRAY},null,Shader.TileMode.REPEAT);        //渐变色设置完毕        p.setShader(mShader);        RectF ova12 = new RectF(120,200,400,480);        canvas.drawArc(ova12,200,130,true,p);        //椭圆        ova12.set(210,100,250,130);        canvas.drawOval(ova12,p);        //画三角形        canvas.drawText("画三角形",10,320,p);        //绘制这个三角形        Path path = new Path();        path.moveTo(80, 300);// 此点为多边形的起点        path.lineTo(120, 250);        path.lineTo(80, 250);        path.close(); // 使这些点构成封闭的多边形        canvas.drawPath(path, p);        p.reset();//重置        p.setColor(Color.LTGRAY);//        p.setStyle(Paint.Style.STROKE);//设置空心//        Path path1=new Path();//        path1.moveTo(180, 200);//        path1.lineTo(200, 200);//        path1.lineTo(210, 210);//        path1.lineTo(200, 220);//        path1.lineTo(180, 220);//        path1.lineTo(170, 210);        //path1.close();//封闭        //canvas.drawPath(path1, p);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        x = event.getX();        y = event.getY();        invalidate();        return true;    }}