Fragment相关

发表于 2016-08-04 阅读次数：

Fragment中监听返回键

//主界面获取焦点,用来监听返回键
private void getFocus() {
    View view = getView();
    if (view == null) {
        return;
    }

    view.setFocusableInTouchMode(true);
    view.requestFocus();
    view.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK) {
                // 监听到返回按钮点击事件
                if (mCbControlSelectAll.getVisibility() == View.VISIBLE) {
                    sync(false);
                    return true;
                }
            }
            return false;
        }
    });
}

Android必知必会-Fragment监听返回键事件

通过调用 fragment 的 `isAdded()` 方法，来判断当前的 fragment 是否阵亡。

具体用法参考：com.example.android.architecture.blueprints.todoapp.tasks.TasksContract.isActive();
isAdded()文档：Return true if the fragment is currently added to its activity.

How to implement onBackPressed() in Fragments?

public interface OnBackPressedListener {
    public void doBack();
}

// create method to set listener in CustomActivity
public void setOnBackPressedListener(OnBackPressedListener onBackPressedListener) {
    this.onBackPressedListener = onBackPressedListener;
}

// in override onBackPressed implement something like that
@Override
public void onBackPressed() {
    if (onBackPressedListener != null)
        onBackPressedListener.doBack();
    else
        super.onBackPressed();
}

// in your fragment in onCreateView you should add our listener
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    activity = getActivity();
    ((CustomActivity)activity).setOnBackPressedListener(new OnBackPressedListener(){
        @override
        public void doBack(){
            // do your logic
        }
    });
    return view;
}

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