Android0917<二十一>（自定义的View、绘制简单图形、Bitmap）(二)

绘制简单图形

下面是Canvas类常用的方法：

drawRect(RectF rect, Paint paint) //绘制区域，参数一为RectF一个区域

drawPath(Path path, Paint paint) //绘制一个路径，参数一为Path路径对象

drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint) //贴图，参数一就是我们常规的Bitmap对象，参数二是源区域(这里是bitmap)，参数三是目标区域(应该在canvas的位置和大小)，参数四是Paint画刷对象，因为用到了缩放和拉伸的可能，当原始Rect不等于目标Rect时性能将会有大幅损失。

drawLine(float startX, float startY, float stopX, float stopY, Paintpaint) //画线，参数一起始点的x轴位置，参数二起始点的y轴位置，参数三终点的x轴水平位置，参数四y轴垂直位置，最后一个参数为Paint 画刷对象。

drawPoint(float x, float y, Paint paint) //画点，参数一水平x轴，参数二垂直y轴，第三个参数为Paint对象。

drawText(String text, float x, floaty, Paint paint) //渲染文本，Canvas类除了上面的还可以描绘文字，参数一是String类型的文本，参数二x轴，参数三y轴，参数四是Paint对象。

drawOval(RectF oval, Paint paint)//画椭圆，参数一是扫描区域，参数二为paint对象；
drawCircle(float cx, float cy, float radius,Paint paint)// 绘制圆，参数一是中心点的x轴，参数二是中心点的y轴，参数三是半径，参数四是paint对象；

drawArc(RectF oval, float startAngle, float sweepAngle, boolean useCenter, Paint paint)//画弧，

参数一是RectF对象，一个矩形区域椭圆形的界限用于定义在形状、大小、电弧，参数二是起始角(度)在电弧的开始，

参数三扫描角(度)开始顺时针测量的，参数四是如果这是真的话,包括椭圆中心的电弧,并关闭它,如果它是假这将是一个弧线,参数五是Paint对象；

还要理解一个paint类：
Paint 代表了Canvas上的画笔、画刷、颜料等等；

Paint类常用方法:

setARGB(int a, int r, int g, int b) // 设置 Paint对象颜色，参数一为alpha透明值

setAlpha(int a) // 设置alpha不透明度，范围为0~255

setAntiAlias(boolean aa) // 是否抗锯齿

setColor(int color) // 设置颜色，这里Android内部定义的有Color类包含了一些常见颜色定义

setTextScaleX(float scaleX) // 设置文本缩放倍数，1.0f为原始

setTextSize(float textSize) // 设置字体大小

setUnderlineText(booleanunderlineText) // 设置下划线

MyPath.java

public class MyPath extends View{    private int width;    private int height;    private Paint mPaint;    private Paint mPaintText;    private Path mPath;    private Path mPathCircle;    private Path mPathLine;    private Paint mPaintLine;    private Path mPathWave;    private Paint mPaintWave;    private static final int WAVE_LINE=0x23;    private int count=0;    private Bitmap mBitmap;    private Handler handler=new Handler(){        @Override        public void handleMessage(Message msg) {            super.handleMessage(msg);            switch(msg.what){                case WAVE_LINE:                    count+=10;                    if (count>160) {                        count = 0;                    }                    invalidate();// 刷新                    handler.sendEmptyMessageDelayed(WAVE_LINE,100);                    break;            }        }    };    public MyPath(Context context) {        super(context);    }    public MyPath(Context context, AttributeSet attrs) {        super(context, attrs);        //设置绘制文字的画笔        mPaintText=new Paint();        mPaintText.setColor(Color.BLUE);        mPaintText.setTextSize(50);//设置画笔大小        mPaintText.setStyle(Paint.Style.STROKE);//消除锯齿        //设置绘制画笔的属性        mPaint=new Paint();        mPaint.setColor(Color.GREEN);        mPaint.setStrokeWidth(10);//设置画笔宽度        mPaint.setStyle(Paint.Style.STROKE);        //设置绘画线段的画笔        mPaintLine=new Paint();        mPaintLine.setColor(Color.RED);        mPaintLine.setStyle(Paint.Style.STROKE);        mPaintLine.setStrokeWidth(10);        //设置绘画波浪线的画笔属性        mPaintWave=new Paint();        mPaintWave.setColor(Color.YELLOW);        mPaintWave.setStrokeWidth(10);        mPaintWave.setStyle(Paint.Style.STROKE);        //设置路径        mPathWave=new Path();//设置波浪线的路径        mPath=new Path();//设置路径        mPathCircle=new Path();//设置圆形的路径        mPathLine=new Path();//设置线段的路径        handler.sendEmptyMessageDelayed(WAVE_LINE, 100);        //设置初始化位图Bitmap，        mBitmap= BitmapFactory.decodeResource(getResources(), R.mipmap.zun);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);        setMeasuredDimension(width,height);//设置画布的大小，长和宽    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        mPath.moveTo(100, 100);//设置路径的第一个点坐标        mPath.lineTo(150,150);//设置下一个点的坐标        mPath.lineTo(100,150);//设置下一个点的坐标        mPath.close();//封闭路径        canvas.drawBitmap(mBitmap,width/2,height/2,mPaint);        //设置圆形路径，Path.Direction设置转动方向，CW是顺时针，CCW是逆时针        mPathCircle.addCircle(width/2,height/2,width/4,Path.Direction.CW);        // canvas.drawPath绘制特定的路径，第一个参数传具体的路径Path实例对象，第二参数传画笔        canvas.drawPath(mPath,mPaint);//设置路径        canvas.drawPath(mPathCircle,mPaint);        //canvas.drawTextOnPath设置文字沿路径排列，第一个参数是文字内容，第二个参数是沿的路径Path实例对象        //第三个参数和第四个参数是横纵偏移量，最后一个是画笔        canvas.drawTextOnPath("我是沿着路径走的一行字",mPathCircle,10,50,mPaintText);        //Path.quadTo用来绘制贝赛尔曲线，前两个参数是控制点的横纵坐标，后两个参数是后一个点的横纵坐标        mPathLine.moveTo(width/8*3,height/8*3);        mPathLine.quadTo(width/2,height/2+width/4,width/8*5,height/8*3);        canvas.drawPath(mPathLine,mPaintLine);        mPathWave.reset();        mPathWave.moveTo(count,height/2+width/16);        //Path.rQuadTo()方法绘制曲线时，会把上一点的坐标当做是原点坐标，依次往后        for (int i=0;i<10;i++){            mPathWave.rQuadTo(40,30,80,0);            mPathWave.rQuadTo(40,-30,80,0);        }        canvas.drawPath(mPathWave,mPaintWave);    }}

activity_path.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical" android:layout_width="match_parent"    android:layout_height="match_parent"  android:background="@mipmap/imagebac"><com.example.administrator.canvas.widget.MyPath    android:layout_width="wrap_content"    android:layout_height="wrap_content" /></LinearLayout>

MyPathActivity.java

public class MyPathActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_path);    }}

Bitmap、Matrix

位于android.graphics.Matrix包下的Matrix是拥有3 x3的坐标变换矩阵的矩阵类。用于对位图进行一些变化

1、Translate—平移变换

 matrix.postTranslate(0,mBitmapHeigtht*2);//沿y轴向下平移Bitmap高的2倍

2、Scale—缩放变换

matrix.postScale(2,2);//放大2倍

3、Rotate—旋转变换

 matrix.postRotate(180);//旋转180度

4、Skew—错切变换

 matrix.postSkew(1,0);//x轴上的值不变，拉伸y轴上的值

5、Values—-对称

 float matrix_values[]={1f,0f,0f,0f,-1f,0f,0f,0f,1f};//关于x轴对称，倒影效果matrix.setValues(matrix_values);float matrix_values2[]={-1f,0f,0f,0f,1f,0f,0f,0f,1f};//关于y轴对称，镜面效果matrix.setValues(matrix_values2);

Bitmap实现在android.graphics包中。Bitmap类的构造函数是私有的，外面并不能实例化.BitmapFactory类提供了创建Bitmap的接口，而JNI接口来实例化Bitmap的.如下：

 mBitmap= BitmapFactory.decodeResource(getResources(), R.mipmap.betterfly);//decodeResource能够从给定的资源中解析出新的位图，第一个参数是包含图像数据的资源对象，第二个参数是图像数据的资源标识

得到位图Bitmap的宽和高

mBitmapWidth=mBitmap.getWidth();//得到位图的宽mBitmapHeigtht =mBitmap.getHeight();//得到位图的高

将位图绘制到画布上,canvas.drawBitmap()方法，第一个参数是位图实例对象Bitmap，第二个和第三个参数是位图得左上角位于画布中的位置，最后一个是画笔

canvas.drawBitmap(mBitmap,0,0,mPaint);

MyBitmap.java

public class MyBitmap extends View {    private int width;    private int height;    private Paint mPaint;    private Bitmap mBitmap;    private Matrix matrix;    private int mBitmapWidth;    private int mBitmapHeigtht;    public MyBitmap(Context context) {        super(context);    }    public MyBitmap(Context context, AttributeSet attrs) {        super(context, attrs);        mPaint=new Paint();        mPaint.setColor(Color.GREEN);        mPaint.setStrokeWidth(10);        mPaint.setStyle(Paint.Style.STROKE);        mBitmap= BitmapFactory.decodeResource(getResources(), R.mipmap.betterfly);        matrix=new Matrix();        mBitmapWidth=mBitmap.getWidth();        mBitmapHeigtht =mBitmap.getHeight();    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);        setMeasuredDimension(width,height);//设置画布的大小，长和宽    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawBitmap(mBitmap,0,0,mPaint);        matrix.reset();        matrix.postScale(2,2);//放大2倍        canvas.drawBitmap(mBitmap,matrix,mPaint);        matrix.reset();;        canvas.drawBitmap(mBitmap,matrix,mPaint);        matrix.postTranslate(0,mBitmapHeigtht*2);//平移        canvas.drawBitmap(mBitmap,matrix,mPaint);        matrix.reset();        matrix.postRotate(180);//旋转        matrix.postTranslate(mBitmapWidth*2,mBitmapHeigtht*3);        canvas.drawBitmap(mBitmap,matrix,mPaint);        matrix.reset();        float matrix_values[]={1f,0f,0f,0f,-1f,0f,0f,0f,1f};//关于x轴对称，倒影效果        matrix.setValues(matrix_values);        matrix.postTranslate(0,mBitmapHeigtht*2);        canvas.drawBitmap(mBitmap,matrix,mPaint);        matrix.reset();;        float matrix_values2[]={-1f,0f,0f,0f,1f,0f,0f,0f,1f};//关于y轴对称，镜面效果        matrix.setValues(matrix_values2);        matrix.postTranslate(mBitmapWidth*2,0);        canvas.drawBitmap(mBitmap,matrix,mPaint);        matrix.reset();        matrix.postSkew(1,0);//拉伸        matrix.postTranslate(0,mBitmapHeigtht*3);        canvas.drawBitmap(mBitmap,matrix,mPaint);    }}

activity_bitmap.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical" android:layout_width="match_parent"    android:layout_height="match_parent"><com.example.administrator.canvas.widget.MyBitmap    android:layout_width="wrap_content"    android:layout_height="wrap_content" /></LinearLayout>

MyBitmapActivity.java

public class MyBitmapActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_bitmap);    }}

位图相交

MyBitmapView.java

public class MyBitmapView extends View {    private int width;    private int height;    private Paint mPaintCircle;    private Paint mPaintRect;    private Bitmap mBitmap;    private Canvas canvasBit;    public MyBitmapView(Context context) {        super(context);    }    public MyBitmapView(Context context, AttributeSet attrs) {        super(context, attrs);        mPaintCircle=new Paint();        mPaintCircle.setColor(Color.YELLOW);        mPaintRect=new Paint();        mPaintRect.setColor(Color.GREEN);    //PorterDuffXfermode(PorterDuff.Mode.XOR)创建一个xfermode使用指定的波特达夫模式。参数为运用波特达夫模式        PorterDuffXfermode modeXOR=new PorterDuffXfermode(PorterDuff.Mode.XOR);        //setXfermode()方法设置或清除xfermode对象。参数为xfermode的实例对象     mPaintRect.setXfermode(modeXOR);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);        setMeasuredDimension(width,height);//设置画布的大小，长和宽//Bitmap.createBitmap()返回与指定的宽度和高度可变的位图。 //Bitmap.Config描述了一个位图结构如何存储像素       mBitmap=Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);        //Canvas(mBitmap)方法用指定的位图构造一个画布来绘制。        canvasBit=new Canvas(mBitmap);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvasBit.drawCircle(width/4,height/4,width/4,mPaintCircle);        canvasBit.drawRect(0,0,width/4,width/4,mPaintRect);        canvas.drawBitmap(mBitmap,0,0,null);    }}

activity_bitmapview.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical" android:layout_width="match_parent"    android:layout_height="match_parent"><com.example.administrator.canvas.widget.MyBitmapView    android:layout_width="wrap_content"    android:layout_height="wrap_content" /></LinearLayout>

MyBitmapView.java

public class MyBitmapViewActivity extends Activity{    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_bitmapview);    }}

MySilder.java

public class MySilder extends View {    private int width;    private int height;    private Paint mPaint;    private Paint mPaintMove;    private String []array={"A","B","C","D","E","F","G",            "H","I","J","K","L","M","N","O","P","Q","R",            "S","T","U","V","W","X","Y","Z"};    private int count=1;    private int index;    private OnItemOnClick listener;    public void setListener(OnItemOnClick listener) {        this.listener = listener;    }    public interface OnItemOnClick{        public void onItemOnClickListener(int index,String indexString);    }    public MySilder(Context context) {        super(context);    }    public MySilder(Context context, AttributeSet attrs) {        super(context, attrs);        mPaint=new Paint();        mPaint.setTextAlign(Paint.Align.CENTER);        mPaintMove=new Paint();        mPaintMove.setTextAlign(Paint.Align.CENTER);        mPaintMove.setColor(Color.RED);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        width=getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec);        height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);        setMeasuredDimension(width,height);//设置画布的大小，长和宽    //设置字体的大小        mPaint.setTextSize(height/26);        mPaintMove.setTextSize(height/26);    }    private  float x,y;    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()){            case MotionEvent.ACTION_MOVE:            case MotionEvent.ACTION_DOWN:                x=event.getX();                y=event.getY();                if (x>width-mPaint.measureText("M")*2) {                    index = (int) (y / (height / 26));                    invalidate();                    if (listener!=null){                        listener.onItemOnClickListener(index ,array[index]);                    }                    return true;                }                    break;            case MotionEvent.ACTION_UP:                count=-1;                invalidate();                return true;        }        return super.onTouchEvent(event);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        for (int i=0;i<26;i++){            canvas.drawText(array[i],width-mPaint.measureText("M"),height/26*(i+1),mPaint);            if (count==1){                canvas.drawText(array[index],width-mPaint.measureText("M"),height/26*(index+1),mPaint);            }else{                canvas.drawText(array[index],width-mPaint.measureText("M"),height/26*(index+1),mPaintMove);            }        }    }}

MySilderActivity.java

public class MySilderActivity extends Activity {    private TextView mTextView;    private MySilder mySilder;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_silder);        mTextView= (TextView) findViewById(R.id.textview);        mySilder= (MySilder) findViewById(R.id.silder);        mySilder.setListener(new MySilder.OnItemOnClick() {            @Override            public void onItemOnClickListener(int index,String indexString) {                mTextView.setText(indexString);            }        });    }}

activity_silder.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <TextView        android:id="@+id/textview"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerInParent="true"        android:textSize="100dp"        android:text="A"        android:textAlignment="center"/><com.example.administrator.canvas.widget.MySilder    android:id="@+id/silder"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_alignParentRight="true"/></RelativeLayout>