Android设置状态栏透明（去除灰色背景）

Hey there! Let's figure out why your XXX and YYY are showing a grey background instead of being transparent. Based on the code snippet you shared and common Android gotchas, here are some actionable fixes to try:

More often than not, that grey color is coming from a parent view or your activity's default theme.

• Head to your styles.xml and look at the theme assigned to HomeActivity. If you see a line like <item name="android:windowBackground">@color/grey</item>, either remove it or set it to <item name="android:windowBackground">@android:color/transparent</item>.
• Double-check the parent layout of your XXX/YYY views too. If the parent has a solid grey background, it'll show through when the child views are set to transparent.

It's easy to mix up the ways to make a view transparent—here are the right methods:

• In XML: Use android:background="@android:color/transparent" (this only makes the background see-through) or android:alpha="0.0" (this makes the entire view, including its content, fully transparent).
• In Java: In your onCreate method, after binding the views, call:

// Replace xxxView and yyyView with your actual view IDs
xxxView.setBackgroundColor(Color.TRANSPARENT);
yyyView.setBackgroundColor(Color.TRANSPARENT);

Since you're using a Toolbar in HomeActivity, if your XXX/YYY are near or part of the Toolbar, its background might be causing the grey hue. Try making the Toolbar transparent too if needed:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_home_layout);
    // ... your existing code
    toolbar.setBackgroundColor(Color.TRANSPARENT);
}

If you're trying to make the status/navigation bar transparent along with your views, incorrect window flags can create a grey overlay. Add these lines early in your onCreate method:

getWindow().setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
getWindow().setStatusBarColor(Color.TRANSPARENT);

Note: FLAG_LAYOUT_NO_LIMITS lets your layout extend under the status bar, so you might need to add top padding to your Toolbar or main content to avoid overlap.

If all else fails, use Android Studio's Layout Inspector to find exactly which view is drawing the grey background:

• Run your app on a device/emulator, then go to Tools > Layout Inspector in Android Studio.
• Select HomeActivity from the list, then hover over the grey area in the preview. The inspector will highlight the view responsible for that background color.

内容的提问来源于stack exchange，提问作者Wallace Blend