Android 在画布上绘制对象/图像
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draw object/image on canvas
提问by lulala
Is there another way to draw an object on a canvas in android?
有没有另一种方法可以在android的画布上绘制对象？
This code inside draw() doesn't work:
draw() 中的此代码不起作用：
Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.pushpin);
canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null); Well actually, it's working on my 1st code but when I've transfered this to another class called MarkOverlay, it's not working anymore.
实际上，它正在处理我的第一个代码，但是当我将它转移到另一个名为 MarkOverlay 的类时，它不再工作了。
markerOverlay = new MarkerOverlay(getApplicationContext(), p);
listOfOverlays.add(markerOverlay); What parameter should I pass to MarkerOverlay to make this code work? The error is somewhere in getResources().
我应该向 MarkerOverlay 传递什么参数才能使此代码工作？错误在 getResources() 中的某个地方。
FYI, canvas.drawOval is perfectly working but I really want to draw an Image not an Oval. :)
仅供参考，canvas.drawOval 工作正常，但我真的想绘制一个图像而不是椭圆形。:)
回答by Nivish Mittal
package com.canvas;
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.view.View;
public class Keypaint extends View {
Paint p;
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
p=new Paint();
Bitmap b=BitmapFactory.decodeResource(getResources(), R.drawable.icon);
p.setColor(Color.RED);
canvas.drawBitmap(b, 0, 0, p);
}
public Keypaint(Context context) {
super(context);
}
}
回答by Emlyn
I prefer to do this as it only generates the image once:
我更喜欢这样做，因为它只生成一次图像：
public class CustomView extends View {
private Drawable mCustomImage;
public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);
mCustomImage = context.getResources().getDrawable(R.drawable.my_image);
}
...
protected void onDraw(Canvas canvas) {
Rect imageBounds = canvas.getClipBounds(); // Adjust this for where you want it
mCustomImage.setBounds(imageBounds);
mCustomImage.draw(canvas);
}
}
