Android绘制文本与图片及动效详解

Android绘制文本 Android绘制图片 Android绘制动效 2022-12-17 12:12:31 944人浏览薄情痞子

摘要

目录绘制文本绘制图片绘制路径逐帧动画补间动画绘制文本绘制类借助 canvas 类进行绘制通过重写View.onDraw 方法来进行旁白描绘 package com.mingri

绘制文本

绘制类借助 canvas 类进行绘制

通过重写View.onDraw 方法来进行旁白描绘

package com.mingrisoft;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);        }    }}

绘制图片

创建位图对象， JAVA 中bitmap 表示位图对象

创建位图对象两种方式：

BitMapFactory :

1. 通过图片文件创建
2. 通过输入流创建

BitMap类挖取一块图像创建，将源位图缩放生成，使用颜色数组创建

BitMapFactory：

1.decodeFile,

2.decodeResource,

3.decodeStream

访问SDK资源需要在Mainiefiest.xml 配置访问权限

<uses-premission android:name="android.permission.READ_EXTERNAL_STOTAHE">

同时在Android 上配置访问权限

package com.example.myapplication;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.FrameLayout;
import androidx.appcompat.app.AppCompatActivity;

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
    }
    }
    class MyView extends View {
        public MyView(Context context) {
            super(context);
        }
        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            // 获取SDK上 图片绘制
            String path  = Environment.getExternalStorageDirectory() + "/snail.png";
            Bitmap bitmap = BitmapFactory.decodeFile(path);
            //通过 canvas 类 绘制图片
            Paint paint = new Paint(); //定义
            canvas.drawBitmap(bitmap,150,150, paint);
            // 从图像中挖取一小片 bitMap 类 的 createBitMap(截取一小块), compress(压缩)
            // 从原始图像挖取小部分
            Bitmap bitmap1 = Bitmap.createBitmap(bitmap,23,89,150,168);
            canvas.drawBitmap(bitmap1,270,50, paint);
        }
    }

绘制路径

通过绘制路径
通过绘制路径的文字

package com.example.myapplication;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Bundle;
import android.view.View;
import android.widget.FrameLayout;
import androidx.appcompat.app.AppCompatActivity;

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
    }
    }
    
    class MyView extends View {
        public MyView(Context context) {
            super(context);
        }
        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            Paint paint = new Paint();
            paint.setAntiAlias(true) ; // 定义抗锯齿
            paint.setColor(0xFF0000FF);
            paint.setStyle(Paint.Style.STROKE); // 设置样式为描边
            Path path = new Path();
            // 最后一个参数环按照 顺时针还是
            path.addCircle(150,100,50,Path.Direction.CW);
          //  canvas.drawPath(path,paint);
            canvas.drawTextOnPath("活着就是为了修改时间", path,0,0,paint);
        }
    }

逐帧动画

创建动画资源文件在drawable 目录下面

使用 animation-list
<?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>

MainActivity 获取AnminationDrawable 方法设置动态图逐帧播放

package com.example.myapplication;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import androidx.appcompat.app.AppCompatActivity;

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(){
            @Override
            public void onClick(View view) {
                if(flag){
                    anim.start();
                    flag = false;
                }else{
                    anim.stop();
                    flag = true;
                }
            }
        });
    }
    }

补间动画

通过手势滑动查看相片的手机相册
创建一个动画资源

参考手势时候 设置动画资源文件
<?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>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
	<alpha android:fromAlpha="1"
	    android:toAlpha="0"
	    android:duration="2000"/>
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <scale android:fromXScale="0.0"
        android:fromYScale="0.0"
        android:pivotX="50%"
        android:pivotY="50%"
        android:toXScale="1.0"
        android:toYScale="1.0"
        android:duration="2000"></scale>
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <scale android:fromXScale="1.0"
        android:fromYScale="1.0"
        android:pivotX="50%"
        android:pivotY="50%"
        android:toXScale="0.0"
        android:toYScale="0.0"
        android:duration="2000"></scale>
</set>

定义并且初始化动画数组
指定切换的动画效果

package com.example.myapplication;
import android.os.Bundle;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.ViewFlipper;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity implements GestureDetector.OnGestureListener {
    ViewFlipper flipper; //定义ViewFlipper
    GestureDetector detector; //定义手势检测器
    Animation[] animation = new Animation[4];//定义动画数组，为ViewFlipper指定切换动画
    final int distance = 50; //定义手势动作两点之间最小距离
    //定义图片数组
    private int[] images = new int[]{R.drawable.img01, R.drawable.img02, R.drawable.img03,
            R.drawable.img04, R.drawable.img05, R.drawable.img06, R.drawable.img07, R.drawable.img08,
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        detector = new GestureDetector(this, this); //创建手势检测器
        flipper = (ViewFlipper) findViewById(R.id.flipper); //获取ViewFlipper
        for (int i = 0; i < images.length; i++) {
            ImageView imageView = new ImageView(this);
            imageView.setImageResource(images[i]);
            flipper.addView(imageView); //加载图片
        }
        //初始化动画数组
        animation[0] = AnimationUtils.loadAnimation(this, R.anim.anim_alpha_in);     //淡入动画
        animation[1] = AnimationUtils.loadAnimation(this, R.anim.anim_alpha_out);      //淡出动画
        animation[2] = AnimationUtils.loadAnimation(this, R.anim.anim_scale_in);      //放大进入动画
        animation[3] = AnimationUtils.loadAnimation(this, R.anim.anim_scale_out);  //缩小退出动画
    }
    @Override
    public boolean onDown(MotionEvent e) {
        return false;
    }
    @Override
    public void onShowPress(MotionEvent e) {
    }
    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        return false;
    }
    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        return false;
    }
    @Override
    public void onLongPress(MotionEvent e) {
    }
    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        
        if (e1.getX() - e2.getX() > distance) {
            //为flipper设置切换的动画效果
            flipper.setInAnimation(animation[0]);
            flipper.setOutAnimation(animation[1]);
            flipper.showPrevious();
            return true;
            
        } else if (e2.getX() - e1.getX() > distance) {
            //为flipper设置切换的动画
            flipper.setInAnimation(animation[2]);
            flipper.setOutAnimation(animation[3]);
            flipper.showNext();
            return true;
        }
        return false;
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        //将该Activity上的触碰事件交给GestureDetector处理
        return detector.onTouchEvent(event);
    }
}

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