Android一些实用的函数

一些Android实用函数收集，不断更新中。

1：获得屏幕的密度，用于屏幕适配

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public static float getDensity(Context ctx) {     DisplayMetrics metrics = new DisplayMetrics();     WindowManager wm = (WindowManager) ctx.getSystemService(Context.WINDOW_SERVICE);     wm.getDefaultDisplay().getMetrics(metrics);     return metrics.density; }

2：获得版本的名字

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public static String getVersionName(Context context, String packageName) {     PackageInfo pInfo = null;     String rs = "";     try {         pInfo = context.getPackageManager().getPackageInfo(packageName, PackageManager.GET_META_DATA);         rs = pInfo.versionName;     }     catch (Exception e) {         e.printStackTrace();         }     return rs; }

3：获得图片的倒影，同时倒影渐变效果

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public static Bitmap createMirro(Bitmap srcbitmap) {        int width = srcbitmap.getWidth();     int height = srcbitmap.getHeight();     int shadow_height = 15;     int[] pixels = new int[width * height];     srcbitmap.getPixels(pixels, 0, width, 0, 0, width, height);        // shadow effect     int alpha = 0x00000000;     for (int y = 0; y < height; y++) {         for (int x = 0; x < width; x++) {             int index = y * width + x;             int r = (pixels[index] >> 16) & 0xff;             int g = (pixels[index] >> 8) & 0xff;             int b = pixels[index] & 0xff;             pixels[index] = alpha | (r << 16) | (g << 8) | b;         }         if (y >= (height - shadow_height)) {             alpha = alpha + 0x1F000000;         }     }            // invert effect     Bitmap bm = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);     for (int y = 0; y < height; y++) {         bm.setPixels(pixels, y * width, width, 0, height - y - 1, width, 1);     }     return Bitmap.createBitmap(bm, 0, 0, width, shadow_height); }