ToolBar是Android 5.0推出的一个新的导航控件用于取代之前的ActionBar，由于其高度的可定制性、灵活性、具有Material Design风格等优点，越来越多的App也用上了ToolBar。
  沉浸式状态栏是从android Kitkat（Android 4.4）开始出现的,它可以被设置成与APP顶部相同的颜色，这就使得切换APP时，整个界面就好似切换到了与APP相同的风格样式一样。

依赖包：

  Toolbar, implementation 'androidx.appcompat:appcompat:1.1.0'
  沉浸式, implementation 'com.gyf.immersionbar:immersionbar:3.0.0'

1、自定义Toolbar步骤：s

1）、定义 /values/styles.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="TextAppearance_TitleBar_Title" parent="TextAppearance.AppCompat.Toolbar.Title">
    ...
    </style>

    <style name="TextAppearance_TitleBar_subTitle" parent="TextAppearance.AppCompat.Toolbar.Subtitle">
      ....
    </style>
</resources>

2）、自定义toolbar 继承 androidx.appcompat.widget.Toolbar

public class CustomToolBar extends Toolbar {
    private TextView mCenterTitle;
    private ImageView mCenterIcon; //中心icon
    private TextView mLeftText;
    private ImageButton mLeftIcon; 
    private TextView mSettingText;
    private ImageButton mSettingIcon;

    public CustomToolBar(Context context) {
        super(context);
    }

    public CustomToolBar(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomToolBar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

  
    public void setLeftText(@StringRes int id) {
        setLeftText(this.getContext().getText(id));
    }

  
    public CustomToolBar setLeftText(CharSequence text) {
        Context context = this.getContext();
        if (this.mLeftText == null) {
            this.mLeftText = new TextView(context);
            this.mLeftText.setGravity(Gravity.CENTER_VERTICAL);
            this.mLeftText.setSingleLine();
//            this.mLeftText.setEllipsize(TextUtils.TruncateAt.END);
            setLeftTextAppearance(getContext(), R.style.TextAppearance_TitleBar_subTitle);
            //textView in left
//            this.addMyView(this.mLeftText, Gravity.START);
            int i = dp2px(this, 16);
            this.addMyView(this.mLeftText, Gravity.START, 0, 0, i, 0, 48);
        }
        mLeftText.setText(text);
        return this;
    }

    public void setLeftTextAppearance(Context context, @StyleRes int resId) {
        if (this.mLeftText != null) {
            this.mLeftText.setTextAppearance(context, resId);
        }
    }

    public void setLeftTextColor(@ColorInt int color) {
        if (this.mLeftText != null) {
            this.mLeftText.setTextColor(color);
        }
    }

    public void setLeftTextOnClickListener(OnClickListener listener) {
        if (mLeftText != null) {
            mLeftText.setOnClickListener(listener);
        }
    }

    public CustomToolBar setLeftIcon(@DrawableRes int resId) {
        return setLeftIcon(ContextCompat.getDrawable(this.getContext(), resId));
    }

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public CustomToolBar setLeftIcon(Drawable drawable) {
        Context context = this.getContext();
        if (this.mLeftIcon == null) {
            this.mLeftIcon = new ImageButton(context);
             ...

            this.addMyView(this.mLeftIcon, Gravity.START);
        } else {
            if (mLeftIcon.getVisibility() != VISIBLE) {
                mLeftIcon.setVisibility(VISIBLE);
            }
        }
        if (mLeftText != null && mLeftText.getVisibility() != GONE) {
            mLeftText.setVisibility(GONE);
        }
        mLeftIcon.setImageDrawable(drawable);
        return this;
    }

    public void setLeftIconOnClickListener(OnClickListener listener) {
        if (mLeftIcon != null) {
            mLeftIcon.setOnClickListener(listener);
        }
    }

    public void setLeftIconVisibility(int visibility) {
        if (mLeftIcon != null) {
            mLeftIcon.setVisibility(visibility);
        }
    }

 
    public CustomToolBar setMyCenterTitle(@StringRes int id, boolean center) {
        return setMyCenterTitle(this.getContext().getText(id), center);
    }

  
    public void setMyCenterTitle(@StringRes int Rid) {
        setMyCenterTitle(this.getContext().getText(Rid));
    }

   public void setMyCenterTitle(CharSequence text) {
        Context context = this.getContext();
        if (this.mCenterTitle == null) {
            this.mCenterTitle = new TextView(context);
          ...

        } else {
            if (this.mCenterTitle.getVisibility() != VISIBLE) {
                mCenterTitle.setVisibility(VISIBLE);
            }
        }
        if (mCenterIcon != null && mCenterIcon.getVisibility() != GONE) {
            mCenterIcon.setVisibility(GONE);
        }
    
      ...

    }
    public CustomToolBar setMyCenterTitle(CharSequence text, boolean center) {
        Context context = this.getContext();
        if (this.mCenterTitle == null) {
            this.mCenterTitle = new TextView(context);

           ...

        } else {
            if (this.mCenterTitle.getVisibility() != VISIBLE) {
                mCenterTitle.setVisibility(VISIBLE);
            }
        }
        if (mCenterIcon != null && mCenterIcon.getVisibility() != GONE) {
            mCenterIcon.setVisibility(GONE);
        }
   
        if (!center) {
            setTitle(text);
            setTitleTextColor(getResources().getColor(R.color.black));
        } else {
            mCenterTitle.setText(text);
            mCenterTitle.setTextColor(getResources().getColor(R.color.black));
            mCenterTitle.setTextSize(16);
        }
        return this;
    }

    public void setMyCenterTextAppearance(Context context, @StyleRes int resId) {
        if (this.mCenterTitle != null) {
            this.mCenterTitle.setTextAppearance(context, resId);
        }
    }

    public void setMyCenterTextColor(@ColorInt int color) {
        if (this.mCenterTitle != null) {
            this.mCenterTitle.setTextColor(color);
        }
    }

    public void setMyCenterTextOnClickListener(OnClickListener listener) {
        if (mCenterTitle != null) {
            mCenterTitle.setOnClickListener(listener);
        }
    }

 
    public void setMyCenterIcon(@DrawableRes int resId) {
        setMyCenterIcon(ContextCompat.getDrawable(this.getContext(), resId));
    }

    public void setMyCenterIcon(Drawable drawable) {
        Context context = this.getContext();
        if (this.mCenterIcon == null) {

         ...

        } else {
            if (mCenterIcon.getVisibility() != VISIBLE) {
                mCenterIcon.setVisibility(VISIBLE);
            }
        }
        if (mCenterTitle != null && mCenterTitle.getVisibility() != GONE) {
            mCenterTitle.setVisibility(GONE);
        }
     
        setTitle("");
        mCenterIcon.setImageDrawable(drawable);
    }

  
    public void setMySettingText(@StringRes int Rid) {
        setMySettingText(this.getContext().getText(Rid));
    }

    public void setMySettingText(CharSequence text) {
        Context context = this.getContext();
        if (this.mSettingText == null) {

           ...

        } else {
            if (mSettingText.getVisibility() != VISIBLE) {
                mSettingText.setVisibility(VISIBLE);
            }
        }
        if (mSettingIcon != null && mSettingIcon.getVisibility() != GONE) {
            mSettingIcon.setVisibility(GONE);
        }
        mSettingText.setText(text);
        mSettingText.setTextSize(14);
        mSettingText.setTextColor(getResources().getColor(R.color.toolbar_title));

    }

    public void setMySettingTextAppearance(Context context, @StyleRes int resId) {
        if (mSettingText != null) {
            mSettingText.setTextAppearance(context, resId);
        }
    }

    public void setMySettingTextColor(@ColorInt int color) {
        if (mSettingText != null) {
            mSettingText.setTextColor(color);
        }
    }

    public void setSettingTextOnClickListener(OnClickListener listener) {
        if (mSettingText != null) {
            mSettingText.setOnClickListener(listener);
        }
    }

    public CustomToolBar setMySettingIcon(@DrawableRes int resId) {
        return setMySettingIcon(ContextCompat.getDrawable(this.getContext(), resId));
//        ViewConfiguration.get(this.getContext()).getScaledTouchSlop();
    }

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public CustomToolBar setMySettingIcon(Drawable drawable) {
        Context context = this.getContext();
        if (this.mSettingIcon == null) {

          ...

        } else {
            if (mSettingIcon.getVisibility() != VISIBLE) {
                mSettingIcon.setVisibility(VISIBLE);
            }
        }
        if (mSettingText != null && mSettingText.getVisibility() != GONE) {
            mSettingText.setVisibility(GONE);
        }
        mSettingIcon.setImageDrawable(drawable);
        return this;
    }

    public void setSettingIconOnClickListener(OnClickListener listener) {
        if (mSettingIcon != null) {
            mSettingIcon.setOnClickListener(listener);
        }
    }

    private void addSimpleView(View v, int gravity) {
        addSimpleView(v, gravity, 0, 0, 0, 0);
    }

    private void addSimpleView(View v, int gravity, int left, int top, int right, int bottom) {
        LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT, gravity);
        lp.setMargins(left, top, right, bottom);
        this.addView(v, lp);
    }

  
    private void addMyView(View v, int gravity) {

        addMyView(v, gravity, 0, 0, dp2px(this, 16), 0);
    }

    private void addMyView(View v, int gravity, int left, int top, int right, int bottom) {
        LayoutParams lp = new LayoutParams(dp2px(this, 20),
                dp2px(this, 20), gravity);
        lp.setMargins(left, top, right, bottom);
        this.addView(v, lp);
    }

    private void addMyView(View v, int gravity, int left, int top, int right, int bottom, int width) {
        LayoutParams lp = new LayoutParams(dp2px(this, width),
                20, gravity);
        lp.setMargins(left, top, right, bottom);
        this.addView(v, lp);
    }


    public CustomToolBar setCenterTitleWithImg(CharSequence text, Drawable drawable, boolean center) {
        Context context = this.getContext();
        if (this.mCenterTitle == null) {
            this.mCenterTitle = new TextView(context);

           ...

            if (this.mCenterTitle.getVisibility() != VISIBLE) {
                mCenterTitle.setVisibility(VISIBLE);
            }
        }

        if (this.mCenterIcon == null) {
            this.mCenterIcon = new ImageView(context);

            ...

        } else {
            if (mCenterIcon.getVisibility() != VISIBLE) {
                mCenterIcon.setVisibility(VISIBLE);
            }
        }

        mCenterTitle.setTextSize(18);
        mCenterTitle.setTextColor(getResources().getColor(R.color.black));
        mCenterTitle.setText(text);
        mCenterIcon.setImageDrawable(drawable);

        return this;
    }

    public void setCenterTitleWithImgOnClickListener(OnClickListener listener) {
        if (mCenterTitle != null) {
            ((View) mCenterTitle.getParent()).setOnClickListener(listener);
        }
    }
}

2、自定义Toolbar使用

1）、res/layout创建布局文件

      <?xml version="1.0" encoding="utf-8"?>
frameLabelStart--frameLabelEnd 

2）、在布局中使用

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:binding="http://schemas.android.com/tools">
    <data>
        <variable
            name="viewModel"
            type="com.android.playandroid.viewmodel.LoginViewModel" />
    </data>
    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/bkg"
        android:orientation="vertical">

        <include
            layout="@layout/title_layout"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
         ...
    </androidx.constraintlayout.widget.ConstraintLayout>

</layout>

3）、代码中使用

##### a、初始化：

    mBinding.root.toolbar.setNavigationIcon(R.mipmap.register_close)
    mBinding.root.toolbar.setMyCenterTitle(getString(R.string.register), true)
    mBinding.root.toolbar.setMySettingText(getString(R.string.login))

##### b、点击事件：

   mBinding.root.toolbar.setNavigationOnClickListener {
        ....
    }

    mBinding.root.toolbar.setSettingTextOnClickListener {
       ...
}

4）、沉浸式，设置toolbar背景颜色、文字颜色，一般写在基类

 protected open fun initImmersionBar() {
        //在BaseActivity里初始化
        mImmersionBar = ImmersionBar.with(this)
        if (toolbar != null) {
            mImmersionBar.titleBar(toolbar)
        }
        mImmersionBar.statusBarDarkFont(true)
    //    mImmersionBar.keyboardEnable(true).navigationBarWithKitkatEnable(false).init()
      //  mImmersionBar.init()
        
       ImmersionBar.with(this).init()
    }

Google原生的效果，不必多说，可以实现类似这样的效果

注意：

1、配置整个app的toolbar风格，在/value/styles.xml文件修改代码

 <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    
        <item name="colorPrimary">@android:color/white</item>
        <item name="colorPrimaryDark">@android:color/white</item>
        <item name="colorAccent">@android:color/white</item>

      ...

    </style>

#### 2、修改了 toolbar的高度 ，怎么让navigationIcon显示在toolbar中心?
  只要设置如下，即可：android:minHeight="@dimen/toolbar_height"

3、toolbar布局文件位置

  如果在commonlibrary目录创建该文件，在app 下还需要复制一份，因为在app 使用toolbar，kotlin-android-extensions引用不到commonlibrary目录下的布局文件。

代码Github：https://github.com/AlbertShen0211/PlayAndroid