Android基础：绘图

一.画笔

import android.app.Fragment;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Shader;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.RelativeLayout;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FrameLayout fragment = (FrameLayout) findViewById(R.id.frameLayout);  //获取帧布局管理器
        fragment.addView(new MyView(this));  //将自定义视图的内部类添加到布局管理器中
    }

    private class MyView extends View {

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


        @Override
        protected void onDraw(Canvas canvas) {  //重写onDraw()方法
            Paint paint = new Paint();           //定义一个默认的画笔
            //线性渐变
            Shader shader = new LinearGradient(0, 0, 100, 100,
                    Color.RED, Color.GREEN, Shader.TileMode.MIRROR);
            paint.setShader(shader);                            //为画笔设置渐变器
            canvas.drawRect(10, 10, 280, 150, paint);                //绘制矩形
            super.onDraw(canvas);
        }
    }
}

二.绘制几何体

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.RelativeLayout;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FrameLayout frameLayout= (FrameLayout) findViewById(R.id.frameLayout);  //获取帧布局管理器
        frameLayout.addView(new MyView(this));  //将自定义视图的内部类添加到布局管理器中
    }

    private class MyView extends View {
        public MyView(Context context) {
            super(context);
        }

        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            Paint paint=new Paint();	//默认设置创建一个画笔
            paint.setAntiAlias(true);	//使用抗锯齿功能
            paint.setColor(0xFFA4C739);	//设置画笔的颜色为绿色
            //绘制机器人的头
            RectF rectf_head=new RectF(10, 10, 100, 100);
            rectf_head.offset(90, 20);
            canvas.drawArc(rectf_head, -10, -160, false, paint);	//绘制弧
            //绘制眼睛
            paint.setColor(Color.WHITE);	//设置画笔的颜色为白色
            canvas.drawCircle(125, 53, 4, paint);	//绘制圆
            canvas.drawCircle(165, 53, 4, paint);	//绘制圆
            paint.setColor(0xFFA4C739);	//设置画笔的颜色为绿色
            //绘制天线
            paint.setStrokeWidth(2);	//设置笔触的宽度
            canvas.drawLine(110, 15, 125, 35, paint);	//绘制线
            canvas.drawLine(180, 15, 165, 35, paint);	//绘制线
            //绘制身体
            canvas.drawRect(100, 75, 190, 150, paint);	//绘制矩形
            RectF rectf_body=new RectF(100,140,190,160);
            canvas.drawRoundRect(rectf_body, 10, 10, paint);	//绘制圆角矩形
            //绘制胳膊
            RectF rectf_arm=new RectF(75,75,95,140);
            canvas.drawRoundRect(rectf_arm, 10, 10, paint);	//绘制左侧的胳膊
            rectf_arm.offset(120, 0);							//设置在X轴上偏移120像素
            canvas.drawRoundRect(rectf_arm, 10, 10, paint);	//绘制右侧的胳膊
            //绘制腿
            RectF rectf_leg=new RectF(115,150,135,200);
            canvas.drawRoundRect(rectf_leg, 10, 10, paint);	//绘制左侧的腿
            rectf_leg.offset(40, 0);							//设置在X轴上偏移40像素
            canvas.drawRoundRect(rectf_leg, 10, 10, paint);	//绘制右侧的腿
        }
    }
}

三.绘制图像

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取布局文件中添加的帧布局管理器
        FrameLayout frameLayout = (FrameLayout) findViewById(R.id.frameLayout);
        frameLayout.addView(new MyView(this)); //将自定义的MyView视图添加到帧布局管理器中
    }

    private class MyView extends View {

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

        @Override
        protected void onDraw(Canvas canvas) {
            Paint paint = new Paint();  //创建一个采用默认设置的画笔
            String path = Environment.getExternalStorageDirectory() + "/HeadImage.jpg";  //指定图片文件的路径
            Bitmap bm = BitmapFactory.decodeFile(path);  //获取图片文件对应的Bitmap对象
            canvas.drawBitmap(bm, 0, 30, paint);   //将获取的Bitmap对象绘制在画布的指定位置
            Rect src = new Rect(105, 70, 220, 170);  //设置挖取的区域
            Rect dst = new Rect(350, 90, 465, 190);  //设置绘制的区域
            canvas.drawBitmap(bm, src, dst, paint);  //绘制挖取到的图像


        }

    }

}

别忘了在使用SD卡资源时需要获取的权限

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

四.逐帧动画

import android.graphics.drawable.AnimationDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;

public class MainActivity extends AppCompatActivity {
    private boolean flag = true;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LinearLayout linearLayout= (LinearLayout) findViewById(R.id.linearLayout); //获取布局管理器
        //获取AnimationDrawable对象
       final AnimationDrawable anim= (AnimationDrawable) linearLayout.getBackground();
        linearLayout.setOnClickListener(new View.OnClickListener() {  //为布局管理器添加单击事件
            @Override
            public void onClick(View v) {
                if(flag){
                    anim.start(); //开始播放动画
                    flag=false;
                }else {
                    anim.stop();  //停止播放动画
                    flag=true;
                }
            }
        });
    }
}

在drawable文件夹中编写动画代码.xml

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/img001" android:duration="60"/>
    <item android:drawable="@drawable/img002" android:duration="60"/>
    <item android:drawable="@drawable/img003" android:duration="60"/>
    <item android:drawable="@drawable/img004" android:duration="60"/>
    <item android:drawable="@drawable/img005" android:duration="60"/>
    <item android:drawable="@drawable/img006" android:duration="60"/>
</animation-list>

五.补间动画

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
	<alpha android:fromAlpha="0"
	    android:toAlpha="1"
	    android:duration="4000"/>
</set>

渐入渐出动画

猜你喜欢