Android自定义控件View的探讨

linear = (LinearLayout) findViewById(R.id.allfack);

callme.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View arg0) {

linear.invalidate();

linear.setDrawingCacheEnabled(true);

linear.measure(

MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),

MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));

linear.layout(0, 0, linear.getMeasuredWidth(),

linear.getMeasuredHeight());

linear.buildDrawingCache();

Bitmap bitmap = linear.getDrawingCache();

if (bitmap != null) {

} else {

Log.e("CACHE_BITMAP", "DrawingCache=null");

}