DPI:每英寸像素数
简单的屏幕分辨率计算方法:
DisplayMetrics metrics = this.getResources().getDisplayMetrics();
float density = metrics.density;
int dpi = metrics.densityDpi;
int heightPixels = metrics.heightPixels;
int widthPixels = metrics.widthPixels;
Log.e("---metrics---", "比例:"+density+"dpi:"+dpi+"高像素:"+heightPixels+"宽像素:"+widthPixels);
dp与px计算图(mdpi 1dp=1px):
ldpi:1dp=0.75px mdpi:1dp=1px hdpi:1dp=1.5px xhdpi:1dp=2px xxhdpi:1dp=3px xxxhdpi:1dp=4px
Android手机屏幕标准 相应图标尺寸标准 屏幕密度比例
xxxhdpi 3840*2160 192*192 64016
xxhdpi 1920*1080 144*144 48012
xhdpi 1280*720 96*96 3208
hdpi 480*80072*72 2406
mdpi 480*32048*48 1604
ldpi 320*24036*36 1203
注:Android studio mipmap目录仅仅存放启动图标icon
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屏幕横竖屏布局切换:
1)单个布局xml直接横竖屏切换。不又一次载入数据:android:configChanges="orientation|keyboardHidden|screenSize"
2)layout-land和layout-port布局横竖屏切换。不又一次载入数据:FragmentActivity重写onRetainCustomNonConfigurationInstance()
Activity 重写onRetainNonConfigurationInstance()保存数据。在onCreate()时推断getLastNonConfigurationInstance()是否null:
Java代码 @Override publicvoidonCreate(BundlesavedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); Objectdata= getLastNonConfigurationInstance(); if(data==null){findviewbyidLoadMyData(); } ... }
很多其它:安卓图片动画(http://www.open-/lib/view/open1335777066015.html)、点九图工具:
1.打开Android project包 SDK文件。tools文件,双击draw9patch.bat
2.弹出的窗体点击 File,点击要编辑的图片open 9patch
3.编辑。鼠标左键:划线 / shift + 鼠标左键:删除划线
4.保存。点击save 9patch