Question

I have a problem with back button. He doesn’t work. When I go from first activity to second and from second to third back button don’t want work. I used :

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        moveTaskToBack(true);
        Log.v("Co1s", "Cos1");
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

But when I push the button I get only:

05-23 10:45:57.863: W/KeyCharacterMap(238): Can’t open keycharmap file
05-23 10:45:57.863: W/KeyCharacterMap(238): Error loading keycharmap
file ‘/system/usr/keychars/pm8058-keypad.kcm.bin’.
hw.keyboards.0.devname=’pm8058-keypad’ 05-23 10:45:57.863:
W/KeyCharacterMap(238): Using default keymap:
/system/usr/keychars/qwerty.kcm.bin

And this log in this function is not showing in logs. Why?

Edit:
acrivity nr1:

protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.services_description);

        back_button = (Button) findViewById(R.id.service_back_button);
        back_button.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                intent = new Intent(services_description.this, service.class);
                TabActivityGroup parentActivity = (TabActivityGroup)getParent();
                parentActivity.startChildActivity("menu_activity", intent);     
                finish();
            }
        });
    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            Log.v("Co1s", "Cos1");
        }
        return super.onKeyDown(keyCode, event);
    }

and second:

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.service);

    title = (TextView) findViewById(R.id.serviceTitle);
    description = (TextView) findViewById(R.id.serviceDescription);
    nextPage = (ImageView) findViewById(R.id.serviceNextPage);
    back_button = (Button) findViewById(R.id.service_back_button);


    nextPage.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            intent = new Intent(service.this, services_description.class);
            TabActivityGroup parentActivity = (TabActivityGroup)getParent();
            parentActivity.startChildActivity("menu_activity", intent);     

        }
    });
    back_button.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {

            finish();

        }
    });
}
@Override
public void onBackPressed() {
    Log.v("Cos", "Cos");
    finish();
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        moveTaskToBack(true);
        Log.v("Co1s", "Cos1");
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

Answer 1

You shouldn’t have to do anything to get the back button working. Just remove the whole block if (keyCode == KeyEvent.KEYCODE_BACK) etc, and you should be all good.

If you for some reason need to log when the back button is clicked, I think you could do it like this:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        Log.v("Co1s", "Cos1");
    }
    return super.onKeyDown(keyCode, event);
}

The important thing is that you pass on the “handling” of the click on the button to the overridden method and let the Android OS itself handle going back to the previous activity.