我是
android的新手,最后(不得不)在这里问一个问题,
让我们简单一点,我只想制作自己的TextView
(MyView扩展了View),
这是我的代码：
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,mPaint);
}
private void initBitmap2() {
mBitmap2 = Bitmap.createBitmap(30,Bitmap.Config.ARGB_4444);
Canvas canvas = new Canvas(mBitmap2);
canvas.drawText(mText,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(),mPaint);
initBitmap2();
canvas.drawBitmap(mBitmap2,30,mPaint);
}
}
在我的代码中,我填充了一些MyView(比方说20)
ListActivity
我的问题是为什么当我滚动时mBitmap1的顺序会随机变化
(快速上下)(如果我慢慢滚动,这个问题不会发生)..？
mBitmap2保留在那些应该是…
解决方法
您必须使用视图持有者类才能克服此问题.这样的事情：
public View getView(final int i,View view,final ViewGroup viewGroup) {
View vi = view;
final ViewHolder holder;
if (view == null) {
holder = new ViewHolder();
vi = inflater.inflate(R.layout.listview_row_cart,null);
holder.yourbutton = (Button) vi.findViewById(R.id.btn);
vi.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
holder.yourbutton.setText("Start");
}
class ViewHolder {
Button yourbutton
}