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我想绘制ImageView,当我尝试创建位图时,程序崩溃。 首先我创建可变在ImageView上绘图 - createBitmap崩溃
private ImageView backgroudn;
在onCreate方法我指出背景在我的xml文件对象。
this.backgroudn = (ImageView) findViewById(R.id.ivbackground);
drawGrid();
可是现在,我要画这个的ImageView的功能drawGrid(),它首先返回我的ImageView为大小宽度= 0和高度= 0。为什么我做了什么错?
private void drawGrid() {
int height = this.backgroudn.getHeight();
int width = this.backgroudn.getWidth();
// return's height = width = 0
System.out.println("height: " + height + " width: " + width);
// where program crashes.
Bitmap bm = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bm);
Paint p = new Paint();
p.setColor(Color.BLACK);
int sizeW = width/7;
int sizeH = height/7;
for (int i = 0; i < 8; i++) {
c.drawLine(i*sizeW, 0, i*sizeW, height, p);
c.drawLine(0, i*sizeH, width, i*sizeH, p);
}
backgroudn.setImageBitmap(bm);
}