问题
At least Gmail and Youtube Android apps use a side menu (navigation drawer?) that opens by swiping, or by clicking the app icon (home button):
Is the menu indicator / icon in the screenshot above a ready-made part of Android SDK? (Or a custom icon Google uses in their apps?) In any case, what's the easiest way to get your home button to look like that, i.e., like it opens a menu?
(targetSdkVersion 18; minSdkVersion 14)
Resolution
Finally got it working. What was missing for me was 1) the actual icon and 2) deferred call to syncState() on the ActionBarDrawerToggle.
回答1:
To create similar implementation / look in your application you should use ActionBarDrawerToggle and set your custom icon as indicator next to ActionBar home button. For example :
import android.app.ActionBar;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.widget.DrawerLayout;
private void setUpDrawerToggle(){
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the navigation drawer and the action bar app icon.
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.navigation_drawer_open, /* "open drawer" description for accessibility */
R.string.navigation_drawer_close /* "close drawer" description for accessibility */
) {
@Override
public void onDrawerClosed(View drawerView) {
invalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
@Override
public void onDrawerOpened(View drawerView) {
invalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
};
// Defer code dependent on restoration of previous instance state.
// NB: required for the drawer indicator to show up!
mDrawerLayout.post(new Runnable() {
@Override
public void run() {
mDrawerToggle.syncState();
}
});
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
Where R.drawable.ic_drawer is actually the icon to use as indicator. You can find it in Android Asset Studio; see Navigation Drawer Indicator.
References
- ActionBarDrawerToggle
- Creating a Navigation Drawer
回答2:
Android-Developer and HpTerm helped me in the right rirection, by
- Pointing out this is indeed NavigationDrawer specific (which I was already using as in Google's example)
- Telling where to find the
ic_drawer.pngicon (→ Android Asset Studio)
Now, unfortunately, creating ActionBarDrawerToggle like below seems not to be enough. At least on my Nexus 7 (API 18) test device.
drawerToggle = new ActionBarDrawerToggle(this,
drawerLayout,
R.drawable.ic_navigation_drawer,
R.string.side_menu_open,
R.string.side_menu_closed) {
// ...
};
Partial solution (API level 18+)
I found one way to make the indicator show up though: setHomeAsUpIndicator(). The downside: that method was added in API level 18.
@Override
protected void onCreate(Bundle savedInstanceState) {
// ...
getActionBar().setDisplayHomeAsUpEnabled(true); // also required
if (Build.VERSION.SDK_INT >= 18) {
getActionBar().setHomeAsUpIndicator(
getResources().getDrawable(R.drawable.ic_navigation_drawer));
}
}
So now the question remains: how to make this work (in my case) for API levels 14 through 17?
I verified on a 4.1.2 (API 16) device that the ic_drawer icon does not show up. With setDisplayHomeAsUpEnabled(true) I get the normal "home" icon (small arrow pointing left) and without it, the space left to my app icon remains blank.
Final solution
Got it working using the edited version of Android-Developer's answer.
Quite curiously, what was missing from my ActionBarDrawerToggle initialisation code was this:
// Defer code dependent on restoration of previous instance state.
drawerLayout.post(new Runnable() {
@Override
public void run() {
mDrawerToggle.syncState();
}
});
With that included, calling setHomeAsUpIndicator() is not needed.
回答3:
The keyword here is NavigationDrawer; there's a full working code example on the Android developer site.
READ THE END OF THE LINK GIVEN : Open and Close with the App Icon
The following code is copied from there
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ActionBarDrawerToggle mDrawerToggle;
...
public void onCreate(Bundle savedInstanceState) {
...
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer icon to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description */
R.string.drawer_close /* "close drawer" description */
) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
}
};
// Set the drawer toggle as the DrawerListener
mDrawerLayout.setDrawerListener(mDrawerToggle);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Pass the event to ActionBarDrawerToggle, if it returns
// true, then it has handled the app icon touch event
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle your other action bar items...
return super.onOptionsItemSelected(item);
}
...
}
Some files are available as download and the small 3 lines with the animation effect is fully exemplified.
You have to copy thoses files in the corresponding drawable folder. Depending on the theme you use, dark or light you have a different set of icons.
In my case I simply copied the drawer_shadow.9.png and ic_drawer.png in the drawable folder and followed the example and everything works just fine.
The icons are available in the link I provided, but they are NOT in the "Action Bar Icon Pack", they are in the sample app in the corresponding res/drawable folders.
来源：https://stackoverflow.com/questions/19724567/how-to-add-menu-indicator-next-to-action-bars-app-icon