我正在处理一系列与Fragment
有关的令人费解的事件。我正在尝试向Activity
添加一个片段,然后在片段中调用一个方法来更新一些文本。然而,我发现在onCreateView()
完成之前,该方法正在片段中进行处理,这给我留下了一个空的View
对象,我的方法失败了。这是Activity
代码:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_log_entry_details);
fragmentManager = getSupportFragmentManager();
titleBarFragment = new TitleBarVerticalFragment();
fragmentTransaction = fragmentManager.beginTransaction ();
fragmentTransaction.add(R.id.log_entry_title_frame, titleBarFragment);
fragmentTransaction.commit();
titleBarFragment.updateTitleBar("Edit Log Entry", 20, false);
}
看起来很简单。这是TitleBarVerticalFragment类:
public class TitleBarVerticalFragment extends TitleBarFragment {
@Inject SharedVisualElements sharedVisualElements;
View view;
TextView titleLabel;
public TitleBarVerticalFragment() {
// add this line for any class that want to use any of the singleton objects
Injector.INSTANCE.getAppComponent().inject(this);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
Log.d(Constants.TAG, "title fragment onCreateView()");
view = inflater.inflate(R.layout.fragment_title_bar_vertical, container, false);
ImageView logoImage = (ImageView) view.findViewById(R.id.logo_vertical);
titleLabel = (TextView) view.findViewById(R.id.verticalTitleLabel);
titleLabel.setTextColor(sharedVisualElements.secondaryFontColor());
titleLabel.setTypeface(sharedVisualElements.font());
titleLabel.setTextSize(20);
logoImage.setImageDrawable(sharedVisualElements.logoImage());
logoImage.setBackgroundColor(Color.TRANSPARENT);
return view;
}
public void updateTitleBar(String text, int textSize, boolean titleLabelIsHidden) {
Log.d(Constants.TAG, "about to update title bar text");
if (view == null) {
Log.d(Constants.TAG, "vertical title fragment is null");
return;
}
if (titleLabel == null)
titleLabel = (TextView) view.findViewById(R.id.verticalTitleLabel);
if (titleLabel == null) {
Log.d(Constants.TAG, "vertical title label is null");
return;
}
Log.d(Constants.TAG, "updating title text: " + text);
titleLabel.setText(text);
titleLabel.setTextSize(textSize);
}
注意这个logcat输出的顺序。注意到onCreateView()
似乎是如何在updateTitleBar()
方法之后运行的吗?怎么可能呢?
即将更新标题栏文本
垂直标题片段为空
CreateView()上的标题片段
在调用片段的任何其他方法之前,如何确保onCreateView()
运行?非常感谢。
尝试在fragmentTransaction.commit()之后运行fragmentManager.executeEndingTransactions();以及在titleBarFragment.updateTitleBar之前("编辑日志条目",20,false);
只需在活动上使用onStart()
定义一个监听器接口并在您的"活动"中实现它。
interface LyfecycleListener {
void onCreatedView();
}
在您的活动中:
@Override
protected void onCreate(Bundle savedInstanceState) {
...
this.titleBarFragment = new TitleBarVerticalFragment();
this.titleBarFragment.setListener(this)
...
}
@Override
public void onCreatedView() {
titleBarFragment.updateTitleBar("Edit Log Entry", 20, false);
}
在您的片段中:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
...
this.listener.onCreatedView();
}