我在这个问题上也浪费了 1 天的时间，但我终于想出了一个办法。
/**
* Controller for the toolbar which will take care of the drop down shadow also on pre-lollipop devices.
* <br/>
* The controller also handles the status bar based on the state of the toolbar.
* <p/>
* Created by <b>Negru Ionut Valentin</b> on <b>20/1/2016</b>.
*/
public class ToolbarController {
private boolean handleStatusBar = false;
private boolean showTitle = true;
/**
* Call this method in onCreate() method of your Activity or in onCreateView() in Fragment
*
* @param view
* The view into which to look for the toolbar
* @param activity
* The activity for which setup the toolbar
*
* @return The toolbar found and customized or {@code null}
*/
public Toolbar initToolbar(View view, Activity activity) {
Toolbar mToolbar = (Toolbar) view.findViewById(R.id.toolbar);
// Valid and visible toolbar - otherwise ignore
if (null != mToolbar && mToolbar.getVisibility() == View.VISIBLE) {
int paddingLeft = mToolbar.getPaddingLeft();
int paddingRight = mToolbar.getPaddingRight();
int paddingBottom = mToolbar.getPaddingBottom();
// Set the top padding of the toolbar to match the status bar height
int paddingTop = new CynnyContextWrapper(activity).getStatusBarHeight();
mToolbar.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP) {
ViewParent parent = mToolbar.getParent();
if (parent instanceof RelativeLayout) {
// Manually create the drop shadow
RelativeLayout.LayoutParams params =
new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
Metrics.convertDpToPixel(4, activity));
View dropShadow = new View(activity);
dropShadow.setBackgroundResource(R.drawable.toolbar_shadow);
params.addRule(RelativeLayout.BELOW, R.id.toolbar);
((RelativeLayout) parent).addView(dropShadow, params);
}
}
if (activity instanceof AppCompatActivity) {
// Check if the Activity actually support ActionBar with Toolbar and set our custom Toolbar for it
((AppCompatActivity) activity).setSupportActionBar(mToolbar);
// Get the actionbar from the activity
ActionBar actionBar = ((AppCompatActivity) activity).getSupportActionBar();
if (null != actionBar) {
// If the actionbar is valid, customize it
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
actionBar.setDisplayShowTitleEnabled(this.showTitle);
mToolbar.setNavigationIcon(R.drawable.ic_arrow_back_selector);
}
}
if (this.handleStatusBar) {
// For showing the status bar
activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
}
} else if (handleStatusBar) {
// Force hide the status bar
activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
}
return mToolbar;
}
/**
* Set the flag indicating if the controller should handle or not the status bar.
*
* @param handleStatusBar
* Flag which indicates if the initialization of the toolbar should also update
* the status bar state (if two calls are made for the init, the last one will
* be taken into consideration).
*
* @return The current toolbar controller.
*/
public ToolbarController setHandleStatusBar(boolean handleStatusBar) {
this.handleStatusBar = handleStatusBar;
return this;
}
/**
* Set the flag indicating if the toolbar should show or hide the title.
*
* @param showTitle
* Flag indicating if the toolbar should also show the title (the title can be changed after the toolbar
* initialization)
*
* @return The current toolbar controller.
*/
public ToolbarController setShowTitle(boolean showTitle) {
this.showTitle = showTitle;
return this;
}
}
在活动中你应该像这样在 onCreate() 方法中使用它：
// Create and customize the Toolbar controller
new ToolbarController().setHandleStatusBar(true).setShowTitle(true)
.initToolbar(((ViewGroup) findViewById(android.R.id.content)).getChildAt(0),
this);
在片段中你应该像这样在 onCreateView() 方法中使用它：
new ToolbarController().setHandleStatusBar(false).setShowTitle(false).initToolbar(resultView, getActivity());
不要忘记在布局中添加您的工具栏并将其 id 设置为android:id="@id/toolbar"。如果你想使用另一个 id，你可以自定义控制器并添加另一个使用你提供的 id 的 setter 方法。
我创建了两个工具栏布局：
v21
<!-- This is the new widget added in Lollipop - use with care -->
<android.support.v7.widget.Toolbar
android:id="@id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?attr/actionBarSize"
android:theme="@style/TitleToolbarTheme"
android:background="?android:attr/colorPrimary"
android:elevation="@dimen/toolbar_elevation"
/>
</merge>
其他
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
>
<!-- This is the new widget added in Lollipop - use with care -->
<android.support.v7.widget.Toolbar
android:id="@id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?attr/actionBarSize"
android:theme="@style/TitleToolbarTheme"
android:background="?attr/colorPrimary"
/>
</merge>
我在可能的布局中使用它们：
<include layout="@layout/toolbar" />
我希望这将有助于解决您的问题。另请注意，这可以进一步优化，但它对我有用，我不想再在这个问题上浪费时间了。