I am new to android, and ended up (have to) ask a question here,
Let's make it simple, I simply want to make my own TextView-like (MyView extends View),
this is my code:
public class MyView extends View {
private Paint mPaint;
private String mText;
private Bitmap mBitmap1;
private Bitmap mBitmap2;
public MyView(Context context) {
super(context);
initView();
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
initView();
}
private final void initView() {
mPaint = new Paint();
}
public void setText(String text) {
mText = text;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int measuredWidth = measureWidth(widthMeasureSpec);
if (mBitmap1 == null) initBitmap1(measuredWidth);
int measuredHeight = measureHeight(heightMeasureSpec);
setMeasuredDimension(measuredWidth, measuredHeight);
}
private void initBitmap1(int measuredWidth) {
mBitmap1 = Bitmap.createBitmap(measuredWidth, Fonts.getHeight(), Bitmap.Config.ARGB_4444);
Canvas canvas = new Canvas(mBitmap1 );
canvas.drawText(mText, 0, 0, mPaint);
}
private void initBitmap2() {
mBitmap2 = Bitmap.createBitmap(30, Fonts.getHeight(), Bitmap.Config.ARGB_4444);
Canvas canvas = new Canvas(mBitmap2);
canvas.drawText(mText, 0, 0, mPaint);
}
private int measureWidth(int widthMeasureSpec) {
int measuredWidth = 0;
int specWidthMode = MeasureSpec.getMode(widthMeasureSpec);
int specWidthSize = MeasureSpec.getSize(widthMeasureSpec);
if (specWidthMode == MeasureSpec.EXACTLY) {
measuredWidth = specWidthSize;
} else {
measuredWidth = getWidth();
if (specWidthMode == MeasureSpec.AT_MOST) {
measuredWidth = Math.min(measuredWidth, specWidthSize);
}
}
return measuredWidth;
}
private int measureHeight(int heightMeasureSpec) {
int measuredHeight = 0;
int specHeightMode = MeasureSpec.getMode(heightMeasureSpec);
int specHeightSize = MeasureSpec.getSize(heightMeasureSpec);
if (specHeightMode == MeasureSpec.EXACTLY) {
measuredHeight = specHeightSize;
} else {
measuredHeight = 80;
if (specHeightMode == MeasureSpec.AT_MOST) {
measuredHeight = Math.min(measuredHeight, specHeightSize);
}
}
return measuredHeight;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(mBitmap1, getLeft(), 0, mPaint);
initBitmap2();
canvas.drawBitmap(mBitmap2, getLeft(), 30, mPaint);
}
}
in my code, i populate some numbers of MyView (let's say 20) in a ListActivity
my question is why mBitmap1's order changes randomly while i scroll (up-down) fastly (if i scroll slowly, this problem not occur)..?
mBitmap2 stays where those should be..