android中view的宽高测量
16lz
2022-04-18
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一般的,view测量的方法:
@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); final ImageView imageView = (ImageView) findViewById(R.id.imageview); int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); imageView.measure(w, h); int height =imageView.getMeasuredHeight(); int width =imageView.getMeasuredWidth(); textView.append("\n"+height+","+width); System.out.println("执行完毕.."+System.currentTimeMillis()); } //------------------------------------------------方法一 int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); imageView.measure(w, h); int height =imageView.getMeasuredHeight(); int width =imageView.getMeasuredWidth(); textView.append("\n"+height+","+width); //-----------------------------------------------方法二 ViewTreeObserver vto = imageView.getViewTreeObserver(); vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { public boolean onPreDraw() { int height = imageView.getMeasuredHeight(); int width = imageView.getMeasuredWidth(); textView.append("\n"+height+","+width); return true; } }); //-----------------------------------------------方法三 ViewTreeObserver vto2 = imageView.getViewTreeObserver(); vto2.addOnGlobalLayoutListener(new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { imageView.getViewTreeObserver().removeGlobalOnLayoutListener(this); textView.append("\n\n"+imageView.getHeight()+","+imageView.getWidth()); } });
最近由于要做自定义view,需要测量view宽高,发现一个不错的api:
View.MeasureSpec.makeMeasureSpec(int,int)
参数1是一个数值,基于该数值计算
参数2是一个mode,指测量的方式,mode如下:
它有三种模式:
①、UNSPECIFIED(未指定),父元素部队自元素施加任何束缚,子元素可以得到任意想要的大小;
②、EXACTLY(完全),父元素决定自元素的确切大小,子元素将被限定在给定的边界里而忽略它本身大小;
③、AT_MOST(至多),子元素至多达到指定大小的值。
具体使用如下:
int w = View.MeasureSpec.makeMeasureSpec(SCREEN_W,View.MeasureSpec.AT_MOST); int h = View.MeasureSpec.makeMeasureSpec(SCREEN_H/2,View.MeasureSpec.AT_MOST); view.measure(w, h);LogUtil.showlog("w:" + w + ",h:" + h);
- intw=View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);
- inth=View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);
- textView.measure(w,h);
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参考:
http://blog.sina.com.cn/s/blog_4172d3d60101h15p.html
http://blog.csdn.net/listening_music/article/details/7210146
http://www.tuicool.com/articles/jiuqEr
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