常用的 utility functions

Utils.java

    // 判斷 app 是否有安裝
    private static boolean isPkgInstalled(Context context, String pkgName) {
        PackageInfo packageInfo = null;
        try {
            packageInfo = context.getPackageManager().getPackageInfo(pkgName, 0);
        } catch (PackageManager.NameNotFoundException e) {
            packageInfo = null;
            e.printStackTrace();
        }
        if (packageInfo == null) {
            return false;
        } else {
            return true;
        }
    }
    
    
    // drawable to bitmap
    public static Bitmap drawableToBitmap(Drawable drawable) {
        // 取 drawable 的长宽
        int w = drawable.getIntrinsicWidth();
        int h = drawable.getIntrinsicHeight();

        // 取 drawable 的颜色格式
        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                : Bitmap.Config.RGB_565;
        // 建立对应 bitmap
        Bitmap bitmap = Bitmap.createBitmap(w, h, config);
        // 建立对应 bitmap 的画布
        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, w, h);
        // 把 drawable 内容画到画布中
        drawable.draw(canvas);
        return bitmap;
    }