setSupportActionBar toolbar cannot be applied to (

问题:

I've been looking for an answer and I've tried many possible solutions, but nothing seems to work..

I'm trying to setup a Material Action Bar following this tutorial.

Here's my code:

tool_bar.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/ColorPrimary"
    android:elevation="4dp">

</android.support.v7.widget.Toolbar>

activity.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFF">
    <!-- The main content view -->
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <include
            android:id="@+id/app_bar"
            layout="@layout/tool_bar" />
    </RelativeLayout>
    <!-- Navigation Drawer -->
    <ListView
        android:id="@+id/left_drawer"
        android:layout_width="220dp"
        android:layout_height="match_parent"
        android:layout_gravity="left"
        android:background="#1C1C1C"
        android:divider="@android:color/darker_gray"
        android:dividerHeight="1dp" />

</android.support.v4.widget.DrawerLayout>

And finally my activity.java:

import android.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toolbar;


public class rutaActivity extends ActionBarActivity {

private Toolbar toolbar;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ruta);

        getSupportActionBar().hide();//Ocultar ActivityBar anterior

        toolbar = (Toolbar) findViewById(R.id.app_bar);
        setSupportActionBar(toolbar); //HERE'S THE PROBLEM !!!!

Error:

setSupporActionBar (android.support.v7.widget.Toolbar) in ActionBarActivity cannot be applied to (android.widget.Toolbar)

How can I fix this?

回答1:

In your Activity.java import android.support.v7.widget.Toolbar instead of android.widget.Toolbar:

import android.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v7.widget.Toolbar;


public class rutaActivity extends AppCompactActivity {

private Toolbar toolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_ruta);

    getSupportActionBar().hide();//Ocultar ActivityBar anterior

    toolbar = (Toolbar) findViewById(R.id.app_bar);
    setSupportActionBar(toolbar); //NO PROBLEM !!!!

回答2:

In using toolbar you should extends AppCompatActivity and then import android.support.v7.widget.Toolbar

回答3:

For adding a ToolBar that supports Material Design, the official documentation directions are probably the best to follow.

1. Add the v7 appcompat support library.

2. Make your activity extend AppCompatActivity.

   public class MyActivity extends AppCompatActivity {
     // ...
   }
   

3. Declare NoActionBar in the Manifest.

   <application
       android:theme="@style/Theme.AppCompat.Light.NoActionBar"
       />
   

4. Add a toolbar to your activity's xml layout.

   <android.support.v7.widget.Toolbar
      android:id="@+id/my_toolbar"
      android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
      ...
      />
   

5. Call setSupportActionBar in the activity's onCreate.

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_my);
       Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
       setSupportActionBar(myToolbar);
   }
   

Note: You will have to import the following in the activity.

import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

回答4:

Certify that your Manifest declaration includes android:theme="@style/AppTheme.NoActionBar" tag, like the following:

<activity
    android:name=".PointsScreen"
    android:theme="@style/AppTheme.NoActionBar">
</activity>

回答5:

Adding import android.support.v7.widget.Toolbar to the import list resolve this issue.

Then add the toolbar widget layout file:

<android.support.v7.widget.Toolbar
    android:id="@+id/list_toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?attr/colorPrimary"
    android:minHeight="?attr/actionBarSize"
    android:theme="?attr/actionBarTheme"
    />

In onCreate method of java code

//call to

Tootbar toolbar = findViewById(R.id.toolbar); setSupportActionBar(toolbar);

Source: https://developer.android.com/training/appbar/up-action

回答6:

import android.support.v7.widget.Toolbar; import it into your java class

回答7:

I was using previously this code:

Toolbar toolbar =  findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

and extended AppCompatActivity also but I was getting the same error. So in place of using Toolbar class, I have imported the below class and it worked for me:

android.support.v7.widget.Toolbar

回答8:

I'm having the same problem. My Logcat says

java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor

I have already an action bar so when i use setSupportActionBar(toolbar); my app gets an error for this conflict. To fix this problem add NoActionBar in your app theme style resource file.

Change this

<style name="ParentMaterialTheme" parent="Theme.AppCompat.Light">

To this

<style name="ParentMaterialTheme" parent="Theme.AppCompat.Light.NoActionBar">

回答9:

With the addition of androidx in Studio 3.0+ the Toolbar compatibility is now in a new library, accessible like this

import androidx.appcompat.widget.Toolbar

回答10:

For android version above 3 :

import androidx.appcompat.widget.Toolbar;

For android version bellow 3 :

import android.widget.Toolbar;

回答11:

In You MainActivity.java import android .support.v7.widget.Toolbar insert of java program