理工女孩

2018更新

因為我本身開發的App跟生命週期是息息相關的

所以如果你也是那還是少用Fragment!!

我曾經有用Fragment開發過

但是那個問題真的多到一個不行

但如果你的App只是單純地要呈現畫面

那你就很適合用Frgment下去做開發！

想要利用Fragment來跳轉頁面，頁面的上方標題不換，只轉換下面的頁面

畫面配置如下

下面的白色頁面 fragment_container 是用來切換頁面的部份

因為我想要在畫面的一開始下面的畫面就有東西，所以在onCreate的時候我就需要將 fragment_container放入東西

我想要切換的畫面為fragment_login

利用這個changeFragment function來將fragment_container取代成想要的畫面

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        changefragmet(fragment_1.newInstance());
    }

    private void changefragmet(android.support.v4.app.Fragment f){
        android.support.v4.app.FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.fragment_container,f);
        transaction.commitNowAllowingStateLoss();
    }

Fragment1

畫面配置如下，讓你想要呈現在fragment_container的畫面直接拉一個layout

按下Button後會切換到fragment2

public class fragment_1 extends Fragment{
    private View v;
    private Button next;

    public static fragment_1 newInstance(){
        fragment_1 f = new fragment_1();
        Bundle arg = new Bundle();
        f.setArguments(arg);
        return f;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        v = inflater.inflate(R.layout.fragment_one,container,false);
        next = (Button)v.findViewById(R.id.next);
        next.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                changefragmet(fragment_2.newInstance());
            }
        });
        return v;
    }

    private void changefragmet(android.support.v4.app.Fragment f){
        android.support.v4.app.FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.fragment_container,f);
        transaction.commitNowAllowingStateLoss();
    }
}

public class fragment_2 extends android.support.v4.app.Fragment{
    private View v;
    private Button back;

    public static fragment_2 newInstance(){
        fragment_2 f = new fragment_2();
        Bundle arg = new Bundle();
        f.setArguments(arg);
        return f;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        v = inflater.inflate(R.layout.fragment_two,container,false);
        back = (Button)v.findViewById(R.id.back);
        back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                changefragmet(fragment_1.newInstance());
            }
        });
        return v;
    }

    private void changefragmet(android.support.v4.app.Fragment f){
        android.support.v4.app.FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.fragment_container,f);
        transaction.commitNowAllowingStateLoss();
    }
}

實際操作畫面會變成下面這樣

下面都是利用Fragment做跳轉