我遇到了使用自定義textview在給定位置顯示給定文本的問題。onDraw無法訪問非靜態變量
我想創建設置成圓形方式ÑMyTextView,使用此代碼:
for (int i = 0; i < player_num ; i++){
x = (x_offset+(raggio*Math.sin((degree_offset)*i)));
y = (y_offset+(raggio*Math.cos((degree_offset)*i)));
//System.out.println("x: "+x+" y: "+y);
player_name = new MyTextView(mCtx,x,y,String.valueOf(i+1));
}
這是我的一塊類延伸的TextView,我通過x,y座標和顯示該字符串的:
public MyTextView(Context context, double x, double y, String text) {
super(context);
System.out.println("constructor called");
mx = x;
my = y;
mtext = text;
initBrushes();
System.out.println("constructor x: "+mx+" y: "+my+" text: "+mtext);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// Get the size of the control based on the last call to onMeasure.
int height = getMeasuredHeight();
int width = getMeasuredWidth();
System.out.println("ondraw called");
System.out.println("draw x: "+mx+" y: "+my+" text: "+mtext);
// Find the center
int px = width/2;
int py = height/2;
// Define the string.
// Measure the width of the text string.
float textWidth = mTextPaint.measureText(mtext);
// Draw the text string in the center of the control.
canvas.drawText(mtext, Math.round(mx) - textWidth/2, Math.round(my)- textWidth, mTextPaint);
//canvas.drawText(this.text, Math.round(this.x), Math.round(this.y), mTextPaint);
}
有了這個代碼,我得到空指針,因爲不能的onDraw訪問的變量的內容,與
System.out.println("draw x: "+mx+" y: "+my+" text: "+mtext);
我得到「0.0 0.0空」,相反,如果我定義變量爲靜態的,我得到分配給他們的(當然)的最後一個值:
constructor called
constructor x: 160.0 y: 320.0 text: 1
constructor called
constructor x: 206.44889473698515 y: 305.1344776421249 text: 2
constructor called
constructor x: 235.63561239368934 y: 266.0625044428118 text: 3
ondraw called
draw x: 235.63561239368934 y: 266.0625044428118 text: 3
我在做什麼錯?爲什麼onDraw無法訪問除靜態類之外的類變量?
謝謝
你能粘貼整個`MyTextView`類? – Cristian 2011-02-04 16:07:57