按下工具欄上的後退按鈕

Question

如何爲我的android應用程序創建代碼當我按下工具欄上的後退按鈕（Action Bar）時，會發生一些代碼。

我試過了，但不起作用。

添加到主要活動。 onbackpress方法

@Override 
public void onBackPressed() { 
    super.onBackPressed(); 
    stopActivityTask(); 
} 

Answer 1

你可以試試這個方式..

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
switch (item.getItemId()) { 
    case android.R.id.home: 
     // this takes the user 'back', as if they pressed the left-facing  

     triangle icon on the main android toolbar. 
     // if this doesn't work as desired, another possibility is to call 

     stopActivityTask(); // finish() here. 
     getActivity().onBackPressed(); 
     return true; 
    default: 
     return super.onOptionsItemSelected(item); 
} 
} 

如果不起作用

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     // Title and subtitle 
     toolbar.setTitle(R.string.about_toolbar_title); 
     toolbar.setNavigationIcon(R.drawable.ic_action_back); 
     toolbar.setNavigationOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       stopActivityTask(); 
       finish(); 
      } 
     }); 

Answer 2

@Override 
    public boolean onOptionsItemSelected(MenuItem item) { 

    int id = item.getItemId(); 

    // click on icon to go back 
    //triangle icon on the main android toolbar. 

    if (id == android.R.id.home) { 
     //your code 
     return true; 
    } 
    return super.onOptionsItemSelected(item); 
} 

Answer 3

private Toolbar toolbar; 

然後在你onCreate方法添加此

toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 

然後添加這些行：

 @Override 
     public boolean onOptionsItemSelected(MenuItem item) { 
     /* 
      ADD WHAT YOU WANT TO DO WHEN ARROW IS PRESSED 
     */ 
     return super.onOptionsItemSelected(item); 
}