第二個活動的標題欄中的後退按鈕

Question

我想在第二個活動的標題欄中添加後退按鈕...這是我當前的代碼...當我點擊活動時....不幸的是，ActionBarMenu已停止.. 。我不知道什麼是錯的吧...請幫我...主營Acticity：

package com.example.hamza.actionbarmenu; 

import android.content.Intent; 
import android.os.Bundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.support.v4.app.NavUtils; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
import android.view.View; 
import android.view.Menu; 
import android.view.MenuItem; 

public class MainActivity extends AppCompatActivity { 

    @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(); 
      } 
     }); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @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.spinner) 
     { 
      Intent intent = new Intent(this, secondActivity.class); 
      startActivity(intent); 
     } 




     return super.onOptionsItemSelected(item); 
    } 
} 




Second Activity... 


package com.example.hamza.actionbarmenu; 

import android.app.ActionBar; 
import android.os.Bundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.support.v4.app.NavUtils; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.content.Intent; 

public class secondActivity extends AppCompatActivity 
{ 
    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_second); 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     ActionBar actionBar = getActionBar(); 
     actionBar.setDisplayHomeAsUpEnabled(true); 

     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(); 
      } 
     }); 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     switch (item.getItemId()) { 
      case android.R.id.home: 
       NavUtils.navigateUpFromSameTask(this); 
       return true; 
     } 
     return super.onOptionsItemSelected(item); 
    } 
} 


menu_main.xml .... 



<menu 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" 
    tools:context="com.example.hamza.actionbarmenu.MainActivity"> 

    <item 
     android:id="@+id/spinner" 
     android:title="@string/title" 
     android:actionViewClass="android.widget.Spinner" 
     android:showAsAction="ifRoom" 
     /> 

    <item 
     android:id="@+id/Orange" 
     android:title="@string/Fruit" 
     android:actionViewClass="android.widget.Spinner" 
     android:showAsAction="ifRoom" 
     /> 

    <item 
     android:id="@+id/Apple" 
     android:title="@string/select" 
     android:actionViewClass="android.widget.Spinner" 
     android:showAsAction="ifRoom" 
     /> 


</menu> 



String.xml .... 


<resources> 
    <string name="app_name">ActionBarMenu</string> 
    <string name="action_settings">Settings</string> 
    <string name="title">Mango</string> 
    <string name="select">Apple</string> 
    <string name="Fruit">Orange</string> 
    <string name="title_activity_third">You Select Apple</string> 
    <string name="title_activity_second">You Select Mango</string> 
    <string name="title_activity_fourth">You Select Orange</string> 
</resources> 


Android Manifest.xml ... 


<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.hamza.actionbarmenu"> 

    <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"> 
      <meta-data 
       android:name="android.support.PARENT_ACTIVITY" 
       android:value="com.example.hamza.actionbarmenu.MainActivity" /> 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity 
      android:name=".secondActivity" 
      android:label="@string/title_activity_second" 
      android:theme="@style/AppTheme.NoActionBar"></activity> 
    </application> 

</manifest> 

Answer 1

創建一個新的Blank Activity' and copy your code in it.空白活動have a working Back`按鈕。

Answer 2

如果您使用Android Studio，通過嚮導創建活動是確保一切正常工作的最佳方式。 Android的內置後退按鈕集成到設備中，因此您不必擔心將某個按鈕放在設備欄中。