NavUtils【底部虚拟导航栏工具类】

前言

获取底部虚拟导航栏的高度值

效果图

代码分析

checkDeviceHasNavigationBar(Context context)：检测是否存在底部虚拟导航栏

getNavigationBarHeight(Context activity)：获取底部虚拟导航栏高度

使用步骤

一、项目组织结构图

注意事项：

1、导入类文件后需要change包名以及重新import R文件路径

2、Values目录下的文件（strings.xml、dimens.xml、colors.xml等），如果项目中存在，则复制里面的内容，不要整个覆盖

二、导入步骤

将NavUtils复制到项目中

package com.why.project.navutilsdemo.utils;

import android.app.Activity;
import android.content.Context;
import android.content.ContextWrapper;
import android.content.res.Resources;
import android.os.Build;
import android.provider.Settings;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Display;
import android.view.WindowManager;

import java.lang.reflect.Method;

/**
 * Created by HaiyuKing
 * Used 底部虚拟导航栏工具类
 */

public class NavUtils {
    private static final String TAG = NavUtils.class.getSimpleName();

    private NavUtils() {
        throw new RuntimeException("NavUtils cannot be initialized!");
    }

    /**
     * 获取状态栏的高度
     */
    public static int getStatusBarHeight(Context context) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            int resourceId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
            return resourceId > 0 ? context.getResources().getDimensionPixelSize(resourceId) : 0;
        } else {
            return 0;
        }
    }

    /**
     * 获取底部虚拟导航栏高度
     * @param activity
     * @return
     */
    public static int getNavigationBarHeight(Context activity) {
        //方法2：有问题
        /*if (!checkDeviceHasNavigationBar(activity)) {
            return 0;
        }
        Resources resources = activity.getResources();
        int resourceId = resources.getIdentifier("navigation_bar_height",
                "dimen", "android");
        //获取NavigationBar的高度
        int height = resources.getDimensionPixelSize(resourceId);
        return height;*/

        //方法1
        boolean hasNavigationBar = navigationBarExist(scanForActivity(activity)) && !vivoNavigationGestureEnabled(activity);
        Log.e(TAG,"{getNavigationBarHeight}hasNavigationBar="+hasNavigationBar);
        if (!hasNavigationBar) {//如果不含有虚拟导航栏，则返回高度值0
            return 0;
        }
        Resources resources = activity.getResources();
        int resourceId = resources.getIdentifier("navigation_bar_height",
                "dimen", "android");
        //获取NavigationBar的高度
        int height = resources.getDimensionPixelSize(resourceId);
        return height;
    }

    /*========================================方法1======================================================*/
    /**
     * 通过获取不同状态的屏幕高度对比判断是否有NavigationBar
     * https://blog.csdn.net/u010042660/article/details/51491572
     * https://blog.csdn.net/android_zhengyongbo/article/details/68941464*/
    public static boolean navigationBarExist(Activity activity) {
        WindowManager windowManager = activity.getWindowManager();
        Display d = windowManager.getDefaultDisplay();

        DisplayMetrics realDisplayMetrics = new DisplayMetrics();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            d.getRealMetrics(realDisplayMetrics);
        }

        int realHeight = realDisplayMetrics.heightPixels;
        int realWidth = realDisplayMetrics.widthPixels;

        DisplayMetrics displayMetrics = new DisplayMetrics();
        d.getMetrics(displayMetrics);

        int displayHeight = displayMetrics.heightPixels;
        int displayWidth = displayMetrics.widthPixels;
        return (realWidth - displayWidth) > 0 || (realHeight - displayHeight) > 0;
    }

    /**解决java.lang.ClassCastException: android.view.ContextThemeWrapper cannot be cast to android.app.Activity问题
     * https://blog.csdn.net/yaphetzhao/article/details/49639097*/
    public static Activity scanForActivity(Context cont) {
        if (cont == null)
            return null;
        else if (cont instanceof Activity)
            return (Activity)cont;
        else if (cont instanceof ContextWrapper)
            return scanForActivity(((ContextWrapper)cont).getBaseContext());

        return null;
    }

    /**
     * 获取vivo手机设置中的"navigation_gesture_on"值，判断当前系统是使用导航键还是手势导航操作
     * @param context app Context
     * @return false 表示使用的是虚拟导航键(NavigationBar)， true 表示使用的是手势， 默认是false
     * https://blog.csdn.net/weelyy/article/details/79284332#更换部分被拉伸的图片资源文件
     */
    public static boolean vivoNavigationGestureEnabled(Context context) {
        int val = Settings.Secure.getInt(context.getContentResolver(), "navigation_gesture_on", 0);
        return val != 0;
    }

    /*========================================方法2======================================================*/
    /**
     * 检测是否有底部虚拟导航栏【有点儿问题，当隐藏虚拟导航栏后，打开APP，仍然判断显示了虚拟导航栏】
     * @param context
     * @return
     */
    public static boolean checkDeviceHasNavigationBar(Context context) {
        boolean hasNavigationBar = false;
        Resources rs = context.getResources();
        int id = rs.getIdentifier("config_showNavigationBar", "bool", "android");
        if (id > 0) {
            hasNavigationBar = rs.getBoolean(id);
        }
        try {
            Class systemPropertiesClass = Class.forName("android.os.SystemProperties");
            Method m = systemPropertiesClass.getMethod("get", String.class);
            String navBarOverride = (String) m.invoke(systemPropertiesClass, "qemu.hw.mainkeys");
            if ("1".equals(navBarOverride)) {
                hasNavigationBar = false;
            } else if ("0".equals(navBarOverride)) {
                hasNavigationBar = true;
            }
        } catch (Exception e) {
        }
        return hasNavigationBar;
    }
}

三、使用方法

package com.why.project.navutilsdemo;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

import com.why.project.navutilsdemo.utils.NavUtils;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    private TextView tv_show;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tv_show = (TextView) findViewById(R.id.tv_show);

        int navigationBarHeight = NavUtils.getNavigationBarHeight(this);
        tv_show.setText("底部虚拟导航栏高度值为："+navigationBarHeight + "，单位为px");
    }
}