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Java 如何将上下文用作if条件_Java_Android_Android Studio - Fatal编程技术网

Java 如何将上下文用作if条件

Java 如何将上下文用作if条件,java,android,android-studio,Java,Android,Android Studio,我正在构建一个应用程序,其中包含多个自定义视图(我们称之为paintview),用户可以在这些视图上画线,每个片段一条。我需要能够使用特定的paintview执行某些操作,但是尽管将paintview(使用id)传递给paintview类,但由于我需要的构造函数,我无法在if条件下对其进行比较,因为它们是不同的数据类型,传递给构造函数的数据类型是上下文(例如:if(Context==R.id.paintView1){..在构造函数中执行操作..})。 有没有办法选择一个特定的paintview来

我正在构建一个应用程序,其中包含多个自定义视图(我们称之为paintview),用户可以在这些视图上画线,每个片段一条。我需要能够使用特定的paintview执行某些操作,但是尽管将paintview(使用id)传递给paintview类,但由于我需要的构造函数,我无法在if条件下对其进行比较,因为它们是不同的数据类型,传递给构造函数的数据类型是上下文(例如:if(Context==R.id.paintView1){..在构造函数中执行操作..})。 有没有办法选择一个特定的paintview来处理它

PaintView.java

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.EmbossMaskFilter;
import android.graphics.MaskFilter;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;

import java.util.ArrayList;

public class PaintView extends View {

public static int BRUSH_SIZE = 10;
public static final int DEFAULT_COLOR = Color.WHITE;
public static int DEFAULT_BG_COLOR = Color.GRAY;
private static final float TOUCH_TOLERANCE = 4;
private float mX, mY;
private Path mPath;
private Paint mPaint;
private ArrayList<FingerPath> paths = new ArrayList<>();
private int currentColor;
private int backgroundColor = DEFAULT_BG_COLOR;
private int strokeWidth;
private boolean emboss;
private boolean blur;
private MaskFilter mEmboss;
private MaskFilter mBlur;
private Bitmap mBitmap;
private Canvas mCanvas;
private Paint mBitmapPaint = new Paint(Paint.DITHER_FLAG);



public PaintView(Context context) {
    this(context, null);
//here is the problem
    if (context == R.id.paintView1) {
        DEFAULT_BG_COLOR = Color.RED;
    }

}

public PaintView(Context context, AttributeSet attrs) {
    super(context, attrs);
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);

    mPaint.setColor(DEFAULT_COLOR);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.ROUND);
    mPaint.setStrokeCap(Paint.Cap.ROUND);
    mPaint.setXfermode(null);
    mPaint.setAlpha(0xff);

    mEmboss = new EmbossMaskFilter(new float[] {1, 1, 1}, 0.4f, 6, 3.5f);
    mBlur = new BlurMaskFilter(5, BlurMaskFilter.Blur.NORMAL);

}

public void init(DisplayMetrics metrics) {
    int height = metrics.heightPixels;
    int width = metrics.widthPixels;

    mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    mCanvas = new Canvas(mBitmap);

    currentColor = DEFAULT_COLOR;
    strokeWidth = BRUSH_SIZE;
}

public void normal() {
    emboss = false;
    blur = false;
}



public void clear() {
    backgroundColor = DEFAULT_BG_COLOR;
    paths.clear();
    normal();
    invalidate();
}

@Override
protected void onDraw(Canvas canvas) {
    canvas.save();
    mCanvas.drawColor(backgroundColor);

    for (FingerPath fp: paths) {
        mPaint.setColor(fp.color);
        mPaint.setStrokeWidth(fp.strokeWidth);
        mPaint.setMaskFilter(null);

        if (fp.emboss)
            mPaint.setMaskFilter(mEmboss);
        else if (fp.blur)
            mPaint.setMaskFilter(mBlur);

        mCanvas.drawPath(fp.path, mPaint);
    }

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

    canvas.restore();
}

private void touchStart(float x, float y) {
    mPath = new Path();
    FingerPath fp = new FingerPath(currentColor, emboss, blur, strokeWidth, mPath);
    paths.add(fp);

    mPath.reset();
    mPath.moveTo(x, y);
    mX = x;
    mY = y;
}

private void touchMove(float x, float y) {
    float dx = Math.abs(x-mX);
    float dy = Math.abs(y-mY);

    if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
        mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
        mX = x;
        mY = y;
    }
}

private void touchUp() {
    mPath.lineTo(mX, mY);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    float x = event.getX();
    float y = event.getY();

    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN :
            touchStart(x, y);
            invalidate();
            break;
        case MotionEvent.ACTION_MOVE :
            touchMove(x, y);
            invalidate();
            break;
        case MotionEvent.ACTION_UP :
            touchUp();
            invalidate();
            break;
    }

    return true;
}
}
导入android.content.Context;
导入android.graphics.Bitmap;
导入android.graphics.BlurMaskFilter;
导入android.graphics.Canvas;
导入android.graphics.Color;
导入android.graphics.maskfilter;
导入android.graphics.MaskFilter;
导入android.graphics.Paint;
导入android.graphics.Path;
导入android.util.AttributeSet;
导入android.util.DisplayMetrics;
导入android.view.MotionEvent;
导入android.view.view;
导入java.util.ArrayList;
公共类PaintView扩展了视图{
公共静态int笔刷大小=10;
公共静态最终int默认值_COLOR=COLOR.WHITE;
公共静态int DEFAULT\u BG\u COLOR=COLOR.GRAY;
专用静态最终浮动接触公差=4;
私人浮动mX,我的;
专用路径mPath;
私人油漆;
私有ArrayList路径=新ArrayList();
私人色彩;
private int backgroundColor=默认背景颜色;
私有内冲程宽度;
私有布尔浮雕;
私有布尔模糊;
私人MaskFilter mEmboss;
私人MaskFilter mBlur;
私有位图mBitmap;
私人帆布mCanvas;
专用油漆mBitmapPaint=新油漆(油漆抖动标志);
公共PaintView(上下文){
这个(上下文,空);
//问题就在这里
if(context==R.id.paintView1){
默认颜色=COLOR.RED;
}
}
公共画图视图(上下文、属性集属性){
超级(上下文,attrs);
mPaint=新油漆();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(默认颜色);
mPaint.setStyle(油漆、样式、笔划);
mPaint.setStrokeJoin(油漆.连接.圆形);
mPaint.setStrokeCap(油漆盖圆形);
mPaint.setXfermode(null);
mPaint.setAlpha(0xff);
mEmboss=新的浮雕maskfilter(新的float[]{1,1,1},0.4f,6,3.5f);
mBlur=新的模糊过滤器(5,BlurMaskFilter.Blur.NORMAL);
}
公共void init(DisplayMetrics){
int height=metrics.heightPixels;
int width=metrics.widthPixels;
mBitmap=Bitmap.createBitmap(宽度、高度、Bitmap.Config.ARGB_8888);
mCanvas=新画布(mBitmap);
currentColor=默认颜色;
笔划宽度=画笔大小;
}
公共无效正常值(){
浮雕=假;
模糊=错误;
}
公共空间清除(){
backgroundColor=默认的背景颜色;
清除路径();
正常();
使无效();
}
@凌驾
受保护的void onDraw(画布){
canvas.save();
mCanvas.drawColor(背景色);
对于(FingerPath fp:路径){
mPaint.setColor(fp.color);
mPaint.设置行程宽度(fp.行程宽度);
mPaint.setMaskFilter(null);
if(fp.浮雕)
mPaint.setMaskFilter(mEmboss);
else if(fp.blur)
mPaint.setMaskFilter(mBlur);
mCanvas.drawPath(fp.path,mPaint);
}
drawBitmap(mBitmap,0,0,mbitMapPoint);
canvas.restore();
}
专用void touchStart(浮点x、浮点y){
mPath=新路径();
FingerPath fp=新的FingerPath(当前颜色、浮雕、模糊、笔划宽度、mPath);
添加路径(fp);
mPath.reset();
移动到(x,y)的速度;
mX=x;
mY=y;
}
私有无效触摸移动(浮动x、浮动y){
float dx=数学绝对值(x-mX);
float dy=Math.abs(y-mY);
如果(dx>=接触公差| | dy>=接触公差){
兆帕四分之一秒(mX,mY,(x+mX)/2,(y+mY)/2);
mX=x;
mY=y;
}
}
私人修补{
mPath.lineTo(mX,mY);
}
@凌驾
公共布尔onTouchEvent(运动事件){
float x=event.getX();
float y=event.getY();
开关(event.getAction()){
case MotionEvent.ACTION\u DOWN:
touchStart(x,y);
使无效();
打破
case MotionEvent.ACTION\u移动:
touchMove(x,y);
使无效();
打破
case MotionEvent.ACTION\u UP:
修补();
使无效();
打破
}
返回true;
}
}