后退按钮上的actionBar不起作用

Question

我有一个<按钮上的actionBar旁边的应用程序标题和+按钮。

我用下面

final ActionBar actionBar = getSupportActionBar(); 
actionBar.setDisplayHomeAsUpEnabled(true); 
actionBar.setHomeAsUpIndicator(R.mipmap.back_to); 

代码创建<按钮，然后

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

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     switch (item.getItemId()) { 
      case R.id.home: // back to previous activity, < button 
       onBackPressed(); 
      break; 

      case R.id.addDetails: 
       mClickedPosition = -1; 
       View menuItemView = findViewById(R.id.addDetails); 
       PopupMenu po = new PopupMenu(this, menuItemView); //for drop-down menu 
       po.getMenuInflater().inflate(R.menu.popup_details, po.getMenu()); 
       po.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() { 
        public boolean onMenuItemClick(MenuItem item) { 
         Toast.makeText(getApplication(), "You Clicked : " + item.getTitle(), Toast.LENGTH_SHORT).show(); 
         if ("Add Work Details".equals(item.getTitle())) { 
          Intent intent = new Intent(getApplication(), Add_Details_Information.class); // go to Details class 
          startActivityForResult(intent, PROJECT_REQUEST_CODE); 
         } else { 

         } 
         return true; 
        } 
       }); 
       po.show(); //showing popup menu 
     } 
     return super.onOptionsItemSelected(item); 

    } 

但只有+按钮的作品。点击<按钮后，如何恢复到之前的活动状态？

Answer 1

只需将R.id.home更改为android.R.id.home即可。