如何在导航栏中添加后退按钮箭头功能

时间：2016-01-28 09:11:33

标签： java android android-studio navigation

我是初学程序员，只是怨恨开始android开发。 看了很多答案，无法找到适合我的答案。 我在操作栏中添加了后退箭头按钮，但无法弄清楚如何将导航添加到第一个加载的屏幕。

  

MainActivity.java 

public class DemoFragment extends Fragment {

public static final String TEXT = "text";

public static DemoFragment newInstance(String text) {

    Bundle args = new Bundle();
    args.putString(TEXT, text);
    DemoFragment fragment = new DemoFragment();
    fragment.setArguments(args);
    return fragment;
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_demo, container, false);
    String text = getArguments().getString(TEXT);
    return view;
}
  

DemoFragment.java 

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>
  

的AndroidManifest.xml 

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">

<include
    layout="@layout/app_bar_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<android.support.design.widget.NavigationView
    android:id="@+id/nav_view"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:fitsSystemWindows="true"
    app:headerLayout="@layout/nav_header_main"
    app:menu="@menu/activity_main_drawer" />

  

activity_main.xml中

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="lt.simbal.drawer.MainActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<include
    android:id="@+id/container"
    layout="@layout/content_main" />

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    android:src="@android:drawable/ic_dialog_email" />

  

app_bar_main.xml 

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="lt.simbal.drawer.MainActivity"
tools:showIn="@layout/app_bar_main">

<TextView
    android:id="@+id/container_text"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="MAIN_ACTIVITY" />

  

content_main.xml 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:id="@+id/text"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

  

fragment_demo.xml 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="@dimen/nav_header_height"
android:background="@drawable/side_nav_bar"
android:gravity="bottom"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:theme="@style/ThemeOverlay.AppCompat.Dark">

<ImageView
    android:id="@+id/imageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingTop="@dimen/nav_header_vertical_spacing"
    android:src="@android:drawable/sym_def_app_icon" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="@dimen/nav_header_vertical_spacing"
    android:text="Android Studio"
    android:textAppearance="@style/TextAppearance.AppCompat.Body1" />

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="android.studio@android.com" />

  

nav_header_main.xml 

<group android:checkableBehavior="single">
    <item
        android:id="@+id/nav_about"
        android:icon="@drawable/ic_menu_camera"
        android:title="@string/about" />

    <item
        android:id="@+id/nav_settings"
        android:icon="@drawable/ic_menu_manage"
        android:title="@string/settings" />
</group>

  

activity_main_drawer.xml 

{{1}}

5 个答案:

答案 0 :(得分：4)

您需要致电 setHomeAsUpIndicator ＆amp;的 setDisplayHomeAsUpEnabled

  

设置备用drawable以显示在图标/徽标/标题旁边   DISPLAY_HOME_AS_UP已启用。如果您正在使用，这可能很有用   此模式显示向上导航的备用选项，例如   滑动抽屉。

ActionBar actionBar = getSupportActionBar();

if (actionBar != null)
{
   ......
   actionBar.setDisplayHomeAsUpEnabled(true); //Set this to true if selecting "home" returns up by a single level in your UI rather than back to the top level or front page.
   actionBar.setHomeAsUpIndicator(R.drawable.Your_Icon); // set a custom icon for the default home button
}

立即

对于此处理，需要在您的活动中覆盖 onOptionsItemSelected(MenuItem item) 方法。

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()) {
    case R.id.home:

       // Add your LOGIC Here
        break;

    default:
        return super.onOptionsItemSelected(item);
    }

    return true;
}

答案 1 :(得分：3)

在onCreate

中添加以下代码 
final ActionBar actionBar = getSupportActionBar();
if (actionBar != null){
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeAsUpIndicator(R.drawable.back_dark);
}

R.drawable.back_dark是后退按钮图片

从您的代码中删除此actionBar.setHomeButtonEnabled(true);

已编辑： 找到一件事，更改以下方法

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    //if (id == R.id.action_settings) {
        //return true;
    //}
    switch (item.getItemId()) {
        // Respond to the action bar's Up/Home button
        case android.R.id.home:
            Toast.makeText(getApplicationContext(),"Back button clicked", Toast.LENGTH_SHORT).show();
            return true;
        case R.id.action_settings:
            return true;
    }
    return super.onOptionsItemSelected(item);
}

否则您的所有代码都是完美的！无需更改naythig

@JonasSeputis：我已经使用你的活动并在Android设备上运行它显示吐司＆＃34;单击后退按钮＆＃34; 检查下面的代码并评论其他代码

public class MainActivity extends AppCompatActivity {

    private DrawerLayout mDrawerLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

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

        ActionBar actionBar = getSupportActionBar();

        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
            actionBar.setHomeButtonEnabled(true);
        }

        /*DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        final ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
            @Override
            public void onBackStackChanged() {
                toggle.setDrawerIndicatorEnabled(getSupportFragmentManager().getBackStackEntryCount() == 0);
            }
        });*/
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        //int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        /*if (id == R.id.action_settings) {
            return true;
        }*/
        switch (item.getItemId()) {
            // Respond to the action bar's Up/Home button
            case android.R.id.home:
                Toast.makeText(getApplicationContext(), "Back button clicked", Toast.LENGTH_SHORT).show();
                return true;
            case R.id.action_settings:
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

答案 2 :(得分：3)

好吧，确保你确实宣布活动布局如下 - 

<activity
    android:name="com.example.myfirstapp.DisplayMessageActivity"
    android:parentActivityName="com.example.myfirstapp.MainActivity" >
    <!-- The meta-data element is needed for versions lower than 4.1 -->
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="com.example.myfirstapp.MainActivity" />
</activity>

现在在每个活动中添加以下代码

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// Respond to the action bar's Up/Home button
case android.R.id.home:
    NavUtils.navigateUpFromSameTask(this);
    return true;
}
return super.onOptionsItemSelected(item);
}

答案 3 :(得分：2)

在你的

中 
@Override
public boolean onOptionsItemSelected(MenuItem item){ 
    if (id == android.R.id.home){
    // add intent to class you wish to navigate
    Intent i = new Intent("com.your.package.classname");
    startActivity(i);

        }
}

答案 4 :(得分：1)

只需添加此行即可 onCreate：

getSupportActionBar().setDisplayHomeAsUpEnabled(true);

相关问题
最新问题