Question

我有一个活动“DashboardActivity”（不是主要的活动）我想要捕获BACK按钮询问他们是否想要注销（因为BACK通常会带你到登录界面）。

我试过了

public void onBackPressed() {
    // ask if they want to logout.....
    logOutIfTheyReallyWantTo();

    //super.onBackPressed();
}

但是在调试器中测试它似乎根本没有碰到代码。

然后我尝试添加

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)  {
    if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.ECLAIR
            && keyCode == KeyEvent.KEYCODE_BACK
            && event.getRepeatCount() == 0) {
        // Take care of calling this method on earlier versions of
        // the platform where it doesn't exist.
        onBackPressed();
    }

    return super.onKeyDown(keyCode, event);
}

这也证明是浪费时间。

最后我尝试了

@Override
public boolean onKeyLongPress(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        // a long press of the call key.
        // do our work, returning true to consume it.  by
        // returning true, the framework knows an action has
        // been performed on the long press, so will set the
        // canceled flag for the following up event.
        return true;
    }
    return super.onKeyLongPress(keyCode, event);
}

但是调试器没有检测到它们。 LogCat仅显示

    05-29 12:22:59.040: D/NetdConnector(14366): RCV <- {217 0}
    05-29 12:22:59.040: D/NetdConnector(14366): RSP <- {217 0}
    05-29 12:23:04.743: V/processReply(32759): sr0857000000
    05-29 12:23:07.673: W/KeyCharacterMap(32759): No keyboard for id 0
    05-29 12:23:07.673: W/KeyCharacterMap(32759): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
    05-29 12:23:07.907: V/Dashboard(32759): Pause
    05-29 12:23:07.915: I/ComfortActivity(32759): start
    05-29 12:23:07.915: V/ComfortActivity(32759): Resume
    05-29 12:23:08.032: D/dalvikvm(14430): GC_EXPLICIT freed 92K, 52% free 3322K/6791K, external 5633K/7003K, paused 77ms
    05-29 12:23:08.329: I/DashboardActivity(32759): stop
    05-29 12:23:08.829: V/processReply(32759): sr0856000000

关于这一点似乎有很多问题，我已经尝试了所有我能找到的建议但到目前为止没有运气。

----回答问题......

void logOutIfTheyReallyWantTo()
{
    AlertDialog.Builder alert = new AlertDialog.Builder(this);
    alert.setTitle("Log out?");
    alert.setMessage("Do you really want to log out?");

    //AlertDialog loginPrompt = alert.create();

    alert.setPositiveButton("OK", new DialogInterface.OnClickListener() 
    {

        public void onClick(DialogInterface dialog, int which) {
            ((ComfortApp) getApplicationContext()).soundClick();

            getComms().logout(true);
            Intent intent = new Intent(DashboardActivity.this, ConfigurationActivity.class);
            startActivityForResult(intent, 0);
        }
    });
    alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener()
    {

        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            // just like Perry the Platypus....
            // don't do much
            ((ComfortApp) getApplicationContext()).soundClick();
        }
    });
    alert.show();

}

Answer 1

覆盖活动中的finish()以捕获退出。如果您不想退出，请不要致电super。

@Override
    public void finish()
    {
        if(!wantToExit)
        {
            super.finish();
        }
        else
        {
            logOutIfTheyReallyWantTo();
        }
    }

onBackPressed()上Activity的默认实现是 -

public void  onBackPressed()
    {
        finish();
    }

Answer 2

您好请尝试以下代码..

@Override
    public void onBackPressed() {
        AlertDialog.Builder alertbox = new AlertDialog.Builder(this);
        alertbox.setMessage("Are you sure logout?");
        alertbox.setTitle("Logout");
        alertbox.setNeutralButton("Yes", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
                showDialog(0);
                new Thread() {
                    public void run() {
                        startActivity(new Intent(DashBoard.this, Login.class));
                        DashBoard.super.onBackPressed();
                    }
                }.start();
            }
        });
        alertbox.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
            }
        });
        alertbox.show();
    }

onBackPressed（）未被调用

2 个答案: