为什么它总是给屏幕英寸尺寸错误？

Question

我想按英寸计算设备尺寸。我正在使用每次搜索都会出现的这段代码。但问题是当我将设备 4.5 英寸放在 android studio 中时，我的答案是 4。我尝试了 5.2 英寸设备，我得到了 4.3 英寸以及 10.1 英寸 -> 答案是 9.0。 那么我怎样才能得到准确的答案呢？

 DisplayMetrics dm = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(dm);

    double wi=(double)dm.widthPixels/dm.xdpi;
    double hi=(double)dm.heightPixels/dm.ydpi;
    double x = Math.pow(wi,2);
    double y = Math.pow(hi,2);
    double screenInches = Math.sqrt(x+y);
    Log.e("hello"," "+screenInches);

Answer 1

你的代码的问题是没有考虑到

操作栏

软键

屏幕方向

使用以下答案

 WindowManager windowManager = getWindowManager();
Display display = windowManager.getDefaultDisplay();
DisplayMetrics displayMetrics = new DisplayMetrics();
display.getMetrics(displayMetrics);

// since SDK_INT = 1;
mWidthPixels = displayMetrics.widthPixels;
mHeightPixels = displayMetrics.heightPixels;

// includes window decorations (statusbar bar/menu bar)
if (Build.VERSION.SDK_INT >= 14 && Build.VERSION.SDK_INT < 17)
{
    try
    {
        mWidthPixels = (Integer) Display.class.getMethod("getRawWidth").invoke(display);
        mHeightPixels = (Integer) Display.class.getMethod("getRawHeight").invoke(display);
    }
    catch (Exception ignored)
    {
    }
}

// includes window decorations (statusbar bar/menu bar)
if (Build.VERSION.SDK_INT >= 17)
{
    try
    {
        Point realSize = new Point();
        Display.class.getMethod("getRealSize", Point.class).invoke(display, realSize);
        mWidthPixels = realSize.x;
        mHeightPixels = realSize.y;
    }
    catch (Exception ignored)
    {
    }


 DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
double x = Math.pow(mWidthPixels/dm.xdpi,2);
double y = Math.pow(mHeightPixels/dm.ydpi,2);
double screenInches = Math.sqrt(x+y);
Log.d("debug","Screen inches : " + screenInches);

感谢him

Answer 2

您可以使用 getResources().getDisplayMetrics()

DisplayMetrics：一种结构，描述有关 展示， 例如它的大小、密度和字体缩放。

DisplayMetrics metrics = getResources().getDisplayMetrics();

    int width = metrics.widthPixels;
    int height = metrics.heightPixels;
    int dens = metrics.densityDpi;
    double wi = (double)width / (double)dens;
    double hi = (double)height / (double)dens;
    double x = Math.pow(wi, 2);
    double y = Math.pow(hi, 2);
    double screenInches = Math.sqrt(x+y);

    System.out.println("getSIZE"+screenInches);

欲了解更多信息，请访问Android DisplayMetrics returns incorrect screen size.

Answer 3

设备尺寸与屏幕尺寸不同，因为屏幕不会覆盖整个设备尺寸

Android 操作系统与设备大小无关，您无法以编程方式获取设备尺寸，您只能获取屏幕尺寸

Answer 4

只需少量更改即可尝试

DisplayMetrics metrics = getResources().getDisplayMetrics();

int width = metrics.widthPixels;
int height = metrics.heightPixels;
int dens = metrics.densityDpi;
double wi = (double)width / (double)dens;
double hi = (double)height / (double)dens;
double x = Math.pow(wi, 2);
double y = Math.pow(hi, 2);
DecimalFormat df = new DecimalFormat("#.#");
df.setRoundingMode(RoundingMode.CEILING);
try {
double screenInches = Double.parseDouble(df.format(Math.sqrt(x+y)));

Log.e("hello"," "+screenInches);
} catch (NumberFormatException e) {

e.printStackTrace();

}