安卓 onBackPressed() 不工作

Question

我正在尝试添加此功能:

-当点击 Return 按钮时，它会弹出一个退出提示 (AlertDialog with yes or no)

问题

但是它不能正常工作。如果我点击按钮，它会直接退出程序。

这是我的整个 Activity 代码:(我测试过的退出函数在代码的末尾)

@SuppressWarnings("deprecation")
public class MainScreen extends TabActivity {
    // TabSpec Names
    private static final String Alerts_SPEC = "Alertes";
    private static final String Status_SPEC = "Status";
    private static final String Details_SPEC = "Events";

    @SuppressWarnings("deprecation")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_screen);

        TabHost tabHost = getTabHost();

        // Inbox Tab
        TabSpec alertsSpec = tabHost.newTabSpec(Alerts_SPEC);
        alertsSpec.setIndicator(Alerts_SPEC);
        Intent alertsIntent = new Intent(this, FragmentAlerts.class);
        alertsSpec.setContent(alertsIntent);

        // Outbox Tab
        TabSpec statusSpec = tabHost.newTabSpec(Status_SPEC);
        statusSpec.setIndicator(Status_SPEC);
        Intent statusIntent = new Intent(this, FragmentStatus.class);
        statusSpec.setContent(statusIntent);

        // Profile Tab
        TabSpec detailsSpec = tabHost.newTabSpec(Details_SPEC);
        detailsSpec.setIndicator(Details_SPEC);
        Intent detailsIntent = new Intent(this, FragmentEvents.class);
        detailsSpec.setContent(detailsIntent);


        // Adding all TabSpec to TabHost
        tabHost.addTab(alertsSpec); // Adding Inbox tab
        tabHost.addTab(statusSpec); // Adding Outbox tab
        tabHost.addTab(detailsSpec); // Adding Profile tab


    }

    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.activity_main_actions, menu);

        return super.onCreateOptionsMenu(menu);
    }

    /**
     * On selecting action bar icons
     * */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Take appropriate action for each action item click
        switch (item.getItemId()) {
        case R.id.action_refresh:
            // refresh
            finish();
            startActivity(getIntent());
            return true;
        case R.id.action_password:
            // help action
            Intent i = new Intent(getApplicationContext(), LoginActivityAdmin.class);
            startActivity(i);
            finish();
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }
// -------------- EXIT CODE BEGINS ------------------------------

    @Override 
    public boolean onKeyDown(int keyCode, KeyEvent event){ 

        if ((keyCode == KeyEvent.KEYCODE_BACK)) { //stop your music here
             // To exit application
            onBackPressed2();
        } 
        return super.onKeyDown(keyCode, event); 
    }

    public void onBackPressed2() {

        new AlertDialog.Builder(this)
               .setMessage("Are you sure you want to exit?")
               .setCancelable(false)
               .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                        MainScreen.this.finish();
                   }
               })
               .setNegativeButton("No", null)
               .show();

    }

}

解决方案:

我为每个 child 添加了这段代码:

@Override
  public void onBackPressed() {
    this.getParent().onBackPressed();   
  }

然后在我的主要 Activity 中调用它:

    @Override 
  public void onBackPressed() {

        new AlertDialog.Builder(this)
               .setMessage("Are you sure you want to exit?")
               .setCancelable(false)
               .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int id) {
                       MainScreen.this.finish();
                   }
               })
               .setNegativeButton("No", null)
               .show();

    }

Answer 1

从这个链接尝试一些东西:

Key Events in TabActivities?

每个选项卡的 Activity 处理“后退”按键。