Android 沉浸式状态栏实践

时间 2019-11-12

原文原文链接

首先明确一下沉浸式状态栏的概念有两种类型android

顶部是ImageView这种须要将其填充到状态栏git
顶部是ActionBar这种不须要填充到状态栏github

而上面的第二种状况覆盖了绝大部分页面，因此下面的思路也是基于这点来实现。ide

第一步：
在BaseActivity里面实现以下代码布局

public abstract class BaseActivity extends AppCompatActivity  {

    @Override
    protected final void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setStatusBar();
    }

    protected void setStatusBar() {
        //这里作了两件事情，1.使状态栏透明并使contentView填充到状态栏 2.预留出状态栏的位置，防止界面上的控件离顶部靠的太近。这样就能够实现开头说的第二种状况的沉浸式状态栏了 
        StatusBarUtil.setTransparent(this);
    }
}

看下StatusBarUtil.setTransparent(this)具体的实现ui

/**
     * 设置状态栏全透明
     *
     * @param activity 须要设置的activity
     */
    public static void setTransparent(Activity activity) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
            return;
        }
        transparentStatusBar(activity);
        setRootView(activity);
    }

    /**
     * 使状态栏透明
     */
    @TargetApi(Build.VERSION_CODES.KITKAT)
    private static void transparentStatusBar(Activity activity) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            //须要设置这个flag contentView才能延伸到状态栏
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
            //状态栏覆盖在contentView上面，设置透明使contentView的背景透出来
            activity.getWindow().setStatusBarColor(Color.TRANSPARENT);
        } else {
            //让contentView延伸到状态栏而且设置状态栏颜色透明
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        }
    }

   /**
     * 设置根布局参数
     */
    private static void setRootView(Activity activity) {
        ViewGroup parent = (ViewGroup) activity.findViewById(android.R.id.content);
        for (int i = 0, count = parent.getChildCount(); i < count; i++) {
            View childView = parent.getChildAt(i);
            if (childView instanceof ViewGroup) {
                childView.setFitsSystemWindows(true);
                ((ViewGroup) childView).setClipToPadding(true);
            }
        }
    }

通过这样的设置基本上大部分界面都适配了沉浸式状态栏了，针对须要适配imageView填充到状态栏或者须要单独设置状态栏颜色和透明度的咱们能够在BaseActivity 的子类重写setStatusBar方法来单独适配。this

第二步：spa

先说简单的，单独设置状态栏颜色和透明度这种状况

//重写这个方法
    protected void setStatusBar() {
        StatusBarUtil.setColor(...);
    }

    /**
     * 设置状态栏颜色
     *
     * @param activity       须要设置的activity
     * @param color          状态栏颜色值
     * @param statusBarAlpha 状态栏透明度
     */

    public static void setColor(Activity activity, @ColorInt int color, @IntRange(from = 0, to = 255) int statusBarAlpha) {
        //5.0以上版本直接设置状态栏颜色透明度
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            activity.getWindow().setStatusBarColor(calculateStatusColor(color, statusBarAlpha));
        //4.4-5.0版本经过假装一个状态栏来设置颜色和透明度
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            ViewGroup decorView = (ViewGroup) activity.getWindow().getDecorView();
            View fakeStatusBarView = decorView.findViewById(FAKE_STATUS_BAR_VIEW_ID);
            if (fakeStatusBarView != null) {
                if (fakeStatusBarView.getVisibility() == View.GONE) {
                    fakeStatusBarView.setVisibility(View.VISIBLE);
                }
                fakeStatusBarView.setBackgroundColor(calculateStatusColor(color, statusBarAlpha));
            } else {
                decorView.addView(createStatusBarView(activity, color, statusBarAlpha));
            }
            setRootView(activity);
        }
    }

    /**
     * 计算状态栏颜色
     *
     * @param color color值
     * @param alpha alpha值
     * @return 最终的状态栏颜色
     */
    private static int calculateStatusColor(@ColorInt int color, int alpha) {
        if (alpha == 0) {
            return color;
        }
        float a = 1 - alpha / 255f;
        int red = color >> 16 & 0xff;
        int green = color >> 8 & 0xff;
        int blue = color & 0xff;
        red = (int) (red * a + 0.5);
        green = (int) (green * a + 0.5);
        blue = (int) (blue * a + 0.5);
        return 0xff << 24 | red << 16 | green << 8 | blue;
    }

    /**
     * 生成一个和状态栏大小相同的半透明矩形条
     *
     * @param activity 须要设置的activity
     * @param color    状态栏颜色值
     * @param alpha    透明值
     * @return 状态栏矩形条
     */
    private static View createStatusBarView(Activity activity, @ColorInt int color, int alpha) {
        // 绘制一个和状态栏同样高的矩形
        View statusBarView = new View(activity);
        LinearLayout.LayoutParams params =
                new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, getStatusBarHeight(activity));
        statusBarView.setLayoutParams(params);
        statusBarView.setBackgroundColor(calculateStatusColor(color, alpha));
        statusBarView.setId(FAKE_STATUS_BAR_VIEW_ID);
        return statusBarView;
    }

    /**
     * 获取状态栏高度
     *
     * @param context context
     * @return 状态栏高度
     */
    public static int getStatusBarHeight(Context context) {
        // 得到状态栏高度
        int resourceId = context.getResources().getIdentifier("status_bar_height", "dimen", "android");
        return context.getResources().getDimensionPixelSize(resourceId);
    }

imageView这种须要填充到状态栏的状况

//重写这个方法
    protected void setStatusBar() {
        StatusBarUtil.setTransparentForImageView(...);
    }

    /**
     * 为头部是 ImageView 的界面设置状态栏全透明
     *
     * @param activity       须要设置的activity
     * @param needOffsetView 须要向下偏移的 View
     */
    public static void setTransparentForImageView(Activity activity, View needOffsetView) {
        setTranslucentForImageView(activity, 0, needOffsetView);
    }

   /**
     * 为头部是 ImageView 的界面设置状态栏透明
     *
     * @param activity       须要设置的activity
     * @param statusBarAlpha 状态栏透明度
     * @param needOffsetView 须要向下偏移的 View
     */
    public static void setTranslucentForImageView(Activity activity, @IntRange(from = 0, to = 255) int statusBarAlpha,
                                                  View needOffsetView) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
            return;
        }
        setTransparentForWindow(activity);
        addTranslucentView(activity, statusBarAlpha);
        //虽然imageView须要填充到状态栏，可是上面的文字按钮等控件并不须要填充到状态栏，因此须要设置偏移
        if (needOffsetView != null) {
            Object haveSetOffset = needOffsetView.getTag(TAG_KEY_HAVE_SET_OFFSET);
            if (haveSetOffset != null && (Boolean) haveSetOffset) {
                return;
            }
            ViewGroup.MarginLayoutParams layoutParams = (ViewGroup.MarginLayoutParams) needOffsetView.getLayoutParams();
            layoutParams.setMargins(layoutParams.leftMargin, layoutParams.topMargin + getStatusBarHeight(activity),
                    layoutParams.rightMargin, layoutParams.bottomMargin);
            needOffsetView.setTag(TAG_KEY_HAVE_SET_OFFSET, true);
        }
    }

    /**
     * 设置透明
     */
    private static void setTransparentForWindow(Activity activity) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            activity.getWindow().setStatusBarColor(Color.TRANSPARENT);
            activity.getWindow()
                    .getDecorView()
                      //两个 flag 要结合使用，表示让应用的主体内容占用系统状态栏的空间
                    .setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            activity.getWindow()
                    .setFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS, WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
        }
    }

    /**
     * 添加半透明矩形条
     *
     * @param activity       须要设置的 activity
     * @param statusBarAlpha 透明值
     */
    private static void addTranslucentView(Activity activity, @IntRange(from = 0, to = 255) int statusBarAlpha) {
        ViewGroup contentView = (ViewGroup) activity.findViewById(android.R.id.content);
        View fakeTranslucentView = contentView.findViewById(FAKE_TRANSLUCENT_VIEW_ID);
        if (fakeTranslucentView != null) {
            if (fakeTranslucentView.getVisibility() == View.GONE) {
                fakeTranslucentView.setVisibility(View.VISIBLE);
            }
            fakeTranslucentView.setBackgroundColor(Color.argb(statusBarAlpha, 0, 0, 0));
        } else {
            contentView.addView(createTranslucentStatusBarView(activity, statusBarAlpha));
        }
    }

    /**
     * 建立半透明矩形 View
     *
     * @param alpha 透明值
     * @return 半透明 View
     */
    private static View createTranslucentStatusBarView(Activity activity, int alpha) {
        // 绘制一个和状态栏同样高的矩形
        View statusBarView = new View(activity);
        LinearLayout.LayoutParams params =
                new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, getStatusBarHeight(activity));
        statusBarView.setLayoutParams(params);
        statusBarView.setBackgroundColor(Color.argb(alpha, 0, 0, 0));
        statusBarView.setId(FAKE_TRANSLUCENT_VIEW_ID);
        return statusBarView;
    }

最后小结一下思路：code

首先在基类设置状态栏透明，让contentView填充到状态栏，利用contentView的背景做为状态栏背景直接实现沉浸的效果，而后利用setFitsSystemWindows(true)和setClipToPadding(true)对控件预留出状态栏的位置。blog

若是须要单独设置状态栏颜色或者透明度，好比contentView的背景色和ActionBar背景不一致的状况，5.0以上经过设置setStatusBarColor实现，4.4-5.0经过假装状态栏实现。

最后若是须要实现相似图片这种须要填充到状态栏的状况，经过setTransparentForWindow实现，而后对其余控件重设MarginLayoutParams来实现预留出状态栏位置的效果。

通过上面的一些设置已经覆盖了绝大部分状况，对于Fragment，DrawerLayout，CoordinatorLayout等可能须要特殊处理的这里贴上gitgub地址。ps：做者不是我，我只是个搬砖的。
https://github.com/laobie/StatusBarUtil