Android 按下工具栏上的“后退”按钮

我如何为我的android应用程序创建一个代码，当我按下工具栏（操作栏）上的后退按钮时，一些代码将发生

我试过了，但没用

添加到主要活动中。反压法

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

然后将其添加到onCreate方法中

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

然后添加以下行：

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

你可以这样试试

@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();
            }
        });

---

检查我的答案：当用户按下后退按钮时，将调用onBackPressed（）方法；如果我没说错的话，你的意思是“主页”按钮。谢谢。。第一个方法起作用。如果第一个方法不起作用，则加载项片段->设置选项菜单（true）

@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);
}
}

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();
            }
        });