我的后退按钮有问题。他不工作。当我从第一个活动转到第二个,从第二个到第三个返回按钮时不想工作。我用了 :
@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);
}
但是当我按下按钮时,我只得到:
05-23 10:45:57.863: W/KeyCharacterMap(238): 无法打开 keycharmap 文件 05-23 10:45:57.863: W/KeyCharacterMap(238): 加载 keycharmap 文件时出错'/system/usr/keychars/ pm8058-keypad.kcm.bin'。hw.keyboards.0.devname='pm8058-keypad' 05-23 10:45:57.863:W/KeyCharacterMap(238):使用默认键盘映射:/system/usr/keychars/qwerty.kcm.bin
并且此功能中的此日志未显示在日志中。为什么?
编辑: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);
    }
第二:
@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);
}