Android 根据屏幕尺寸适配控件尺寸（按比例缩放）

来源：互联网发布：联迪a8安装软件编辑：程序博客网时间：2024/05/16 12:03

在做facebook登录时，正好看到其SDK中一段代码，可以根据屏幕像素适配自己的控件的大小，虽然自己以前也做过类似的逻辑，但不如人家的逻辑来的严谨，这里贴出来学习一下：

    // width below which there are no extra margins    private static final int NO_PADDING_SCREEN_WIDTH = 480;    // width beyond which we're always using the MIN_SCALE_FACTOR    private static final int MAX_PADDING_SCREEN_WIDTH = 800;    // height below which there are no extra margins    private static final int NO_PADDING_SCREEN_HEIGHT = 800;    // height beyond which we're always using the MIN_SCALE_FACTOR    private static final int MAX_PADDING_SCREEN_HEIGHT = 1280;private void calculateSize() {        WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);        Display display = wm.getDefaultDisplay();        DisplayMetrics metrics = new DisplayMetrics();        display.getMetrics(metrics);        // always use the portrait dimensions to do the scaling calculations so we always get a portrait shaped        // web dialog        int width = metrics.widthPixels < metrics.heightPixels ? metrics.widthPixels : metrics.heightPixels;        int height = metrics.widthPixels < metrics.heightPixels ? metrics.heightPixels : metrics.widthPixels;        int dialogWidth = Math.min(                getScaledSize(width, metrics.density, NO_PADDING_SCREEN_WIDTH, MAX_PADDING_SCREEN_WIDTH),                metrics.widthPixels);        int dialogHeight = Math.min(                getScaledSize(height, metrics.density, NO_PADDING_SCREEN_HEIGHT, MAX_PADDING_SCREEN_HEIGHT),                metrics.heightPixels);        getWindow().setLayout(dialogWidth, dialogHeight);     }

    // the minimum scaling factor for the web dialog (50% of screen size)    private static final double MIN_SCALE_FACTOR = 0.5;/**     * Returns a scaled size (either width or height) based on the parameters passed.     * @param screenSize a pixel dimension of the screen (either width or height)     * @param density density of the screen     * @param noPaddingSize the size at which there's no padding for the dialog     * @param maxPaddingSize the size at which to apply maximum padding for the dialog     * @return a scaled size.     */    private int getScaledSize(int screenSize, float density, int noPaddingSize, int maxPaddingSize) {        int scaledSize = (int) ((float) screenSize / density);        double scaleFactor;        if (scaledSize <= noPaddingSize) {            scaleFactor = 1.0;        } else if (scaledSize >= maxPaddingSize) {            scaleFactor = MIN_SCALE_FACTOR;        } else {            // between the noPadding and maxPadding widths, we take a linear reduction to go from 100%            // of screen size down to MIN_SCALE_FACTOR            scaleFactor = MIN_SCALE_FACTOR +                    ((double) (maxPaddingSize - scaledSize))                            / ((double) (maxPaddingSize - noPaddingSize))                            * (1.0 - MIN_SCALE_FACTOR);        }        return (int) (screenSize * scaleFactor);    }

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