android很实用的工具类

 
public class CommonUtil {
  
    public static boolean hasSDCard() {
  
        String status = Environment.getExternalStorageState();
        return status.equals(Environment.MEDIA_MOUNTED);
    }
  
    /**
     * 获取最大内存
     * 
     * @return
     */
    public static long getMaxMemory() {
  
        return Runtime.getRuntime().maxMemory() / 1024;
    }
  
    /**
     * 检查网络
     * 
     * @param context
     * @return
     */
    public static boolean checkNetState(Context context) {
  
        boolean netstate = false;
        ConnectivityManager connectivity = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivity != null) {
  
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null) {
                for (int i = 0; i < info.length; i++) {
  
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {
  
                        netstate = true;
                        break;
                    }
                }
            }
        }
        return netstate;
    }
  
    public static void showToast(Context context,String tip) {
  
        Toast.makeText(context,tip,Toast.LENGTH_SHORT).show();
    }
  
    public static DisplayMetrics metric = new DisplayMetrics();
  
    /**
     * 得到屏幕高度
     * 
     * @param context
     * @return
     */
    public static int getScreenHeight(Activity context) {
  
        context.getWindowManager().getDefaultDisplay().getMetrics(metric);
        return metric.heightPixels;
    }
  
    /**
     * 得到屏幕宽度
     * 
     * @param context
     * @return
     */
    public static int getScreenWidth(Activity context) {
  
        context.getWindowManager().getDefaultDisplay().getMetrics(metric);
        return metric.widthPixels;
    }
  
    /**
     * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
     */
  
    public static int dip2px(Context context,float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }
  
    /**
     * 根据手机的分辨率从 px(像素) 的单位 转成为 dp
     */
    public static int px2dip(Context context,float pxValue) {
  
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }
  
    /**
     * 查询手机内非系统应用
     * 
     * @param context
     * @return
     */
    public static List<PackageInfo> getAllApps(Context context) {
  
        List<PackageInfo> apps = new ArrayList<PackageInfo>();
        PackageManager pManager = context.getPackageManager();
        // 获取手机内所有应用
        List<PackageInfo> paklist = pManager.getInstalledPackages(0);
        for (int i = 0; i < paklist.size(); i++) {
            PackageInfo pak = (PackageInfo) paklist.get(i);
            // 判断是否为非系统预装的应用程序
            if ((pak.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) <= 0) {
                // customs applications
                apps.add(pak);
            }
        }
        return apps;
    }
  
    public static Bitmap zoomBitmap(Bitmap bitmap,int width,int height) {
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
        Matrix matrix = new Matrix();
        float scaleWidth = ((float) width / w);
        float scaleHeight = ((float) height / h);
        matrix.postScale(scaleWidth,scaleHeight);
        Bitmap newbmp = Bitmap.createBitmap(bitmap,w,h,matrix,true);
        return newbmp;
    }
  
    /**
     * 获取版本号和版本次数
     * 
     * @param context
     * @return
     */
    public static String getVersionCode(Context context,int type) {
  
        try {
  
            PackageInfo pi = context.getPackageManager().getPackageInfo(
                    context.getPackageName(),0);
            if (type == 1) {
  
                return String.valueOf(pi.versionCode);
            } else {
  
                return pi.versionName;
            }
        } catch (NameNotFoundException e) {
  
            e.printStackTrace();
            return null;
        }
    }
  
    // 通过Service的类名来判断是否启动某个服务
    public static boolean messageServiceIsStart(
            List<ActivityManager.RunningServiceInfo> mServiceList,String className) {
  
        for (int i = 0; i < mServiceList.size(); i++) {
            if (className.equals(mServiceList.get(i).service.getClassName())) {
  
                return true;
            }
        }
        return false;
    }
}