在处理片段onNewIntent [英] Handling onNewIntent in Fragment

问题描述

我写一个使用NFC读取存储在它的一些数据的应用程序。我的应用程序使用的片段和片段不来onNewIntent（）方法。一直以来，我读的数据与我不同的类，它处理NFC相关的操作完成后，我需要做的唯一的事情就是更新片段内的TextView。然而，该实现也可以用来新意图传递给片段。

I am writing an application that uses NFC to read some data stored on it. My application uses Fragments and Fragment don't come with onNewIntent() method. Since, the data I am reading is done with my separate class which handles NFC related operation, the only thing I need to do is update the TextView inside the Fragment. However this implementation can also be used to pass new Intent to the Fragment.

这是我目前的执行，这使得使用接口。在收到后的新意图和NFC相关检查成功，我呼吁听众。这是它承载片段FragmentActivity。

Here is my current implementation which makes use of an interface. I am calling the listener after new Intent is received and NFC related checks succeeds. This is the FragmentActivity which hosts Fragment.

public class Main extends FragmentActivity implements
    ActionBar.OnNavigationListener {

private Bundle myBalanceBundle;
private NFC nfcObj;
private NewBalanceListener newBlanceListener;

@Override
public void onNewIntent(Intent intent) {
    setIntent(intent);
}

@Override
protected void onResume() {
    getNFCState();
    super.onResume();
}

private void getNFCState() {
    //Other NFC related codes
    else if (nfc_state == NFC.NFC_STATE_ENABLED){
        readNFCTag();
    }
}

private void readNFCTag() {
    //Other NFC related codes
    if (getIntent().getAction().equals(NfcAdapter.ACTION_TECH_DISCOVERED)) {
        nfcObj.setTag((Tag) getIntent().getParcelableExtra(
                NfcAdapter.EXTRA_TAG));
        nfcObj.readQuickBalance();

        transitQuickReadFragment(nfcObj.getCurrentBalance());
    }
}

private void transitQuickReadFragment(String balance) {
    // Creates a balance bundle and calls to select MyBalance Fragment if it
    // is not visible. Calls listener is it is already visible.
    if (actionBar.getSelectedNavigationIndex() != 1) {
        if (myBalanceBundle == null)
            myBalanceBundle = new Bundle();

        myBalanceBundle.putString(Keys.BALANCE.toString(), balance);

        actionBar.setSelectedNavigationItem(1);
    } else {
        newBlanceListener.onNewBalanceRead(balance);
    }
}

@Override
public boolean onNavigationItemSelected(int position, long id) {
    // Other fragment related codes
    fragment = new MyBalance();
    fragment.setArguments(myBalanceBundle);
    newBlanceListener = (NewBalanceListener) fragment;
    // Other fragment related codes
}

// Interface callbacks. You can pass new Intent here if your application
// requires it.
public interface NewBalanceListener {
    public void onNewBalanceRead(String newBalance);

}
}

这是MyBalance片段有TextView的需要，每当NFC读取进行更新：

This is MyBalance Fragment which has TextView that needs to be updated whenever NFC is read:

public class MyBalance extends Fragment implements NewBalanceListener {

private TextView mybalance_value;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    //Other onCreateView related code

    Bundle bundle = this.getArguments();
    if (bundle != null)
        mybalance_value.setText(bundle.getString(Keys.BALANCE.toString(),
                "0.00"));
    else
        mybalance_value.setText("0.00");

    //Other onCreateView related code
}

@Override
public void onNewBalanceRead(String newBalance) {
    mybalance_value.setText(newBalance);
}
}

这code完美的作品像预期为我的应用程序，但是，我想知道是否有更好的方式来处理来自片段新意图是什么？

This code works perfectly like expected for my application but, I want to know if there is better way to handle new Intent from Fragments?

推荐答案

没有，有没有更好的办法。片段可以活得比较长的活动，并不一定依赖于它们在所有所以提供了新的意图就没有意义了。

No, there is no better way. Fragments can live longer than Activities and are not necessarily tied to them at all so providing new intents would not make sense.

顺便说一句，你有你的code几个错误：）

Btw, you have a few bugs in your code :)

if (actionBar.getSelectedNavigationIndex() != 1) {

魔术数字是坏！使用常量。

Magic numbers are bad! use a constant.

    if (myBalanceBundle == null)
        myBalanceBundle = new Bundle();

    myBalanceBundle.putString(Keys.BALANCE.toString(), balance);
    actionBar.setSelectedNavigationItem(1);

我们已经知道，navigationitem设定为1

we already know that the navigationitem is set to 1

} else {
    newBlanceListener.onNewBalanceRead(balance);

添加一个空检查。用户可能从来没有选择的导航项目。

Add a null check. The user might have never selected a navigation item.

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