昨天我遇到问题-findViewById（）为我的工具栏返回NULL。我一直在寻找整个合作伙伴，但似乎找不到“大”问题的解决方案：D
这是styles.xml
<resources>
<style name = "AppTheme" parent = "@style/Theme.AppCompat.NoActionBar">
<!-- TODO: Create AppTheme -->
<item name="android:windowActionBar">false</item>
</style>
</resources>
这里是activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android = "http://schemas.android.com/apk/res/android"
xmlns:tools = "http://schemas.android.com/tools"
android:id = "@+id/drawer_layout"
android:layout_width = "match_parent"
android:layout_height = "match_parent"
tools:context = ".Main" >
<LinearLayout
android:orientation="vertical"
android:layout_width = "fill_parent"
android:layout_height = "fill_parent" >
<android.support.v7.widget.Toolbar
android:id="@+id/tool_bar"
android:layout_width = "fill_parent"
android:layout_height = "@dimen/toolbar_height"
android:background = "@mipmap/bg_toolbar" >
<ImageView
android:id = "@+id/toolbar_drawer_button"
android:clickable="true"
android:layout_width = "wrap_content"
android:layout_height = "@dimen/toolbar_height"
android:src = "@mipmap/ic_drawer" />
<TextView
android:id = "@+id/toolbar_title"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:layout_gravity = "center"
android:text = "@string/app_name"
android:textColor = "@color/toolbar_text"
android:textSize = "@dimen/toolbar_text_size"
android:textStyle = "bold|italic" />
<ImageView
android:id = "@+id/toolbar_settings"
android:clickable="true"
android:layout_width = "wrap_content"
android:layout_height = "@dimen/toolbar_height"
android:layout_gravity = "right"
android:background = "@android:color/transparent"
android:padding = "8dp"
android:src = "@mipmap/ic_settings" />
</android.support.v7.widget.Toolbar>
<FrameLayout
android:id = "@+id/view_container"
android:background="@mipmap/bg_main"
android:layout_width = "match_parent"
android:layout_height = "match_parent" />
</LinearLayout>
<ListView
android:id = "@+id/drawer"
android:layout_width = "@dimen/drawer_width"
android:layout_height = "match_parent"
android:layout_gravity = "left"
android:gravity = "center_vertical"
android:background = "@mipmap/bg_drawer" />
</android.support.v4.widget.DrawerLayout>
这是Main.java：
public class Main extends AppCompatActivity
{
private DrawerAdapter drawerAdapter;
private String[] drawerTitles;
private DrawerLayout drawerLayout;
private ArrayList< DrawerItem > drawerItems;
private TypedArray drawerIcons;
private ListView drawerList;
private Toolbar toolbar;
private ImageView drawerButton;
private LayoutInflater lInflater;
private FrameLayout view_container;
private Converter converter;
@Override protected void onCreate( Bundle savedInstanceState )
{
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_main );
lInflater = ( LayoutInflater ) getApplicationContext( ).getSystemService( LAYOUT_INFLATER_SERVICE );
/** Identifying views **/
view_container = ( FrameLayout ) findViewById( R.id.view_container );
drawerLayout = ( DrawerLayout ) findViewById( R.id.drawer_layout );
drawerList = ( ListView ) findViewById( R.id.drawer );
drawerItems = new ArrayList<>( );
toolbar = ( Toolbar ) drawerLayout.findViewById( R.id.tool_bar );
/** Setting toolbar as action bar **/
SetupToolbar( );
/** Getting resources **/
drawerTitles = getResources( ).getStringArray( R.array.drawer_categories );
drawerIcons = getResources( ).obtainTypedArray( R.array.drawer_icons );
/** Filling drawer with items ( rows ) **/
for( int i = 0; i < drawerTitles.length; i++ )
drawerItems.add( new DrawerItem( drawerTitles[ i ], drawerIcons.getResourceId( i, -1 ) ) );
/** Clearing icon array **/
drawerIcons.recycle( );
/** Setting drawer adapter **/
drawerAdapter = new DrawerAdapter( getApplicationContext( ), drawerItems );
drawerList.setAdapter( drawerAdapter );
/** Making drawer items selectable **/
drawerList.setOnItemClickListener( new DrawerItemClickListener( ) );
}
private void SetupToolbar( )
{
toolbar.bringToFront( );
if( toolbar != null )
{
setSupportActionBar( toolbar );
setTitle( null );
drawerButton = ( ImageView ) findViewById( R.id.toolbar_drawer_button );
if( drawerButton != null )
{
drawerButton.setOnClickListener( new View.OnClickListener( )
{
@Override public void onClick( View v )
{
if( drawerLayout.isDrawerOpen( drawerList ) )
drawerLayout.closeDrawer( drawerList );
else
drawerLayout.openDrawer( drawerList );
}
} );
}
}
}
public class DrawerItemClickListener implements AdapterView.OnItemClickListener
{
@Override public void onItemClick( AdapterView< ? > parent, View view, int position, long id )
{
view_container.removeAllViews( );
switch( position )
{
case 0:
lInflater.inflate( R.layout.fragment_distance, view_container );
break;
case 1:
lInflater.inflate( R.layout.fragment_volume, view_container );
break;
default:
Toast.makeText( getApplicationContext( ), "NOT YET READY !!!", Toast.LENGTH_SHORT ).show( );
break;
}
drawerLayout.closeDrawer( drawerList );
}
}
}
我尝试了很多不同的东西，但似乎都没有用。提前致谢！ ：）
由于某种原因，我的Android Studio开始默认使用CustomView，该视图不允许我编辑布局。它以一个主题开始，该主题在右下方包括工具栏和邮件图标。 mainAcitivty.java然后正在寻找该工具栏和fab，那里不再存在。
在mainAcitivty.java替换中：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
与此]
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
您必须在样式文件夹中放置样式。
您要在Avtivity中导入哪个工具栏？必须为android.support.v7.widget.Toolbar另外，您可以尝试更改toolbar = ( Toolbar ) drawerLayout.findViewById( R.id.tool_bar );至
将toolbar = ( Toolbar ) drawerLayout.findViewById( R.id.tool_bar );更改为toolbar = ( Toolbar ) findViewById( R.id.tool_bar );。
好吧，不确定如何，但是通过删除toolbar.bringToFront( ); ...固定了整个事情。
感谢大家的回答！
我认为它将在更新的Android Studio中工作.....导入androidx.appcompat.widget.Toolbar;