Android开发

android获取屏幕宽高与获取控件宽高(三种方法)

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1.获取屏幕宽高

方法1:

int screenWidth = getWindowManager().getDefaultDisplay().getWidth(); // 屏幕宽(像素,如:480px) 
int screenHeight = getWindowManager().getDefaultDisplay().getHeight(); // 屏幕高(像素,如:800p) 
Log.e(TAG + " getDefaultDisplay", "screenWidth=" + screenWidth + "; screenHeight=" + screenHeight); 

方法2:

DisplayMetrics dm = new DisplayMetrics(); 
dm = getResources().getDisplayMetrics(); 
float density = dm.density; // 屏幕密度(像素比例:0.75/1.0/1.5/2.0) 
int densityDPI = dm.densityDpi; // 屏幕密度(每寸像素:120/160/240/320) 
float xdpi = dm.xdpi; 
float ydpi = dm.ydpi; 
Log.e(TAG + " DisplayMetrics", "xdpi=" + xdpi + "; ydpi=" + ydpi); 
Log.e(TAG + " DisplayMetrics", "density=" + density + "; densityDPI=" + densityDPI); 
screenWidth = dm.widthPixels; // 屏幕宽(像素,如:480px) 
screenHeight = dm.heightPixels; // 屏幕高(像素,如:800px) 
Log.e(TAG + " DisplayMetrics(111)", "screenWidth=" + screenWidth + "; screenHeight=" + screenHeight); 

方法3:

dm = new DisplayMetrics(); 
getWindowManager().getDefaultDisplay().getMetrics(dm); 
density = dm.density; // 屏幕密度(像素比例:0.75/1.0/1.5/2.0) 
densityDPI = dm.densityDpi; // 屏幕密度(每寸像素:120/160/240/320) 
xdpi = dm.xdpi; 
ydpi = dm.ydpi; 
Log.e(TAG + " DisplayMetrics", "xdpi=" + xdpi + "; ydpi=" + ydpi); 
Log.e(TAG + " DisplayMetrics", "density=" + density + "; densityDPI=" + densityDPI); 
int screenWidthDip = dm.widthPixels; // 屏幕宽(dip,如:320dip) 
int screenHeightDip = dm.heightPixels; // 屏幕宽(dip,如:533dip) 
Log.e(TAG + " DisplayMetrics(222)", "screenWidthDip=" + screenWidthDip + "; screenHeightDip=" + screenHeightDip); 
screenWidth = (int)(dm.widthPixels * density + 0.5f); // 屏幕宽(px,如:480px) 
screenHeight = (int)(dm.heightPixels * density + 0.5f); // 屏幕高(px,如:800px) 
Log.e(TAG + " DisplayMetrics(222)", "screenWidth=" + screenWidth + "; screenHeight=" + screenHeight); 

2.获取控件的宽高,一般来说,我们在onCreate里面得到的控件的宽高全是0.采用下面的方法,可以得到真实的宽高

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); 

此方法会加载onMeasure三次

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; 
  } 
}); 

此方法会加载onMeasure二次,但是回调函数会回调很多次

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()); 
  }  
}); 

此方法会加载onMeasure二次,但是回调函数只回调一次  

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