全沉浸式

我们选择使用Activty，来完全自定义导航的方式
首先我们要创建values-v19的样式
下面是v19的style

    <style name="ImmersionTheme">
        <item name="android:windowTranslucentNavigation">true</item>
        <item name="android:windowTranslucentStatus">true</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:background">#ff00beb4</item>
    </style>

下面是Activty的代码

public class MainActivity extends Activity {

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

        Window window = this.getWindow();
        window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS
                | WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
        window.getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
        window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP){
            window.setStatusBarColor(Color.TRANSPARENT);
            window.setNavigationBarColor(Color.TRANSPARENT);
        }
    }
}