创建新的活动时，不能添加片段 [英] Can't add a fragment when Creating a new Activity
问题描述
我想要创建一个向导一样的Android应用程序，我想创建一个活动，两个动态片段，在创建活动时，第一个将被添加，第二时在一个按钮，用户点击第一个片段，现在我不能连片段添加到活动：
i'm trying to create a wizard Like Android application, i want to Create an activity and Two dynamic Fragments, the first one will be added when the Activity is created, and the second when the user clicks on a button in the First fragment, right now i can't even add the Fragment to the activity :
活动onCreate方法：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Fragment fr = new FragmentNumber();
getSupportFragmentManager().beginTransaction().add(fr, "number_fragment").commit();
}
这是我的活动code，当我运行这一点，屏幕是空白的。
this is my activity code, when i run this, the screen is blank.
在R.layout.activity_main指一个空的线性布局，我不希望添加的片段那里，因为我需要他们是动态的。
the R.layout.activity_main refer to an empty Linear Layout, i don't want to add the fragments there because i need them to be dynamic.
先谢谢了。
编辑：粘贴多个文件
activity_main.xml中
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="hello from main"
/>
</FrameLayout>
MaicActivity.java
package com.example.fragmenttraining;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;
公共类MainActivity扩展ActionBarActivity {
public class MainActivity extends ActionBarActivity{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(findViewById(android.R.id.content) != null)
{
Log.d("main activity", "content found");
}
FragmentNumber fr = new FragmentNumber();
//getSupportFragmentManager().beginTransaction().add(android.R.id.content, fr, "number_fragment").commit();
getSupportFragmentManager().beginTransaction().replace(android.R.id.content, fr).commit();
}
FragmentNumber numberFragment;
FragmentFacebook facebookFragment;
public void facebookClicked(View view)
{
numberFragment = new FragmentNumber();
numberFragment.facebookClicked(view);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
现在它的工作，但片段没有更换，它显示的activity_main +的FragmentNumber片段的内容的内容甚至ID我更换...
Now it's working, but the fragment is not replaced, it displays the content of the activity_main + the content of the FragmentNumber fragment even id i replace it ...
推荐答案
请按照下列步骤操作：
- 创建主（活动布局）文件。在这里面，添加一个框架布局，将作为您的碎片的容器。
- 现在，创建两个片段。这包括创建，将您的片段的 onCreateView 方法内被夸大两个XML文件。
- 您的一个片段（第一个）应该有一个按钮，用户将能够点击。也就是说，你必须通过ID找到它后附加一个onClick监听器，它onCreateView方法中。
- 现在，创建您的第一个分片里面一个接口，它添加了一个方法，你的活动应该实现后的界面覆盖。
- 当用户点击该按钮，OnClick方法里面，你应该调用接口方法通知click事件的活动。
- 活动里面，当方法被调用时，创建第二个片段的新实例，并添加它通过更换第一个视图 - 或者这取决于你是否在你的活动用两个窗格布局 - 在情况下，你只需要添加的片段。
- 记住之前简单地增加一个视图来检查，如果你的第一个片段存在。
- Create your main (activity layout) file. In it, add a frame layout which will act as a container for your fragments.
- Now create your two fragments. This involves creating two xml files that will be inflated inside your fragment's onCreateView method.
- One of your fragments (the first one) should have a button that the user will be able to click. That means you must attach an onClick listener to it inside the onCreateView method after finding it by id.
- Now create an interface inside your first fragment and add a method in it that your activity should override after implementing the interface.
- When the user clicks that button, inside onClick method, you should call the interface method to notify the activity of the click event.
- Inside the activity, when the method is called, create a new instance of the second fragment and add it to view by replacing the first one - or it depends on whether you are using two-pane layout in your activity - in that case, you just add the fragment.
- Remember to check if your fragment exists first before simply adding one to view.
我希望这些步骤能够帮助你。
I hope these steps help you.
样品code
public class WizardActivity extends Activity implements SecondFragment.OnButtonClickedListener
{
private FirstFragment firstFragment;
public void onCreate(Bundle saveInstanceState)
{
super.onCreate(saveInstanceState);
setContentView(R.layout.main);
firstFragment = new FirstFragment();
setFragment(firstFragment, "firstFragment");
}
@Override
public void loadSecondFragment()
{
SecondFragment secondFragment = new SecondFragment();
setFragment(secondFragment, "secondFragment");
}
public void setFragment(Fragment frag, String tag)
{
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
Fragment fragment = getFragmentManager().findFragmentById(R.id.fragmentContainer);
if(fragment == null)
{
ft.add(R.id.fragmentContainer, frag, tag);
} else {
ft.replace(R.id.fragmentContainer, frag, tag);
}
ft.addToBackStack(null);
ft.commit()
}
}
现在为主要布局的XML文件。
Now the xml file for main layout.
<LinearLayout ........>
<!--add whatever you need here-->
<FrameLayout
android:id="@+id/fragmentContainer"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
现在让我们来创建你的片段中的一个 - 第一个：
Now let us create one of your fragments - the first one:
FirstFragment.java
public class FirstFragment extends Fragment implements View.OnClickListener
{
private Activity mActivity;
@Override
public void onAttach(Activity act)
{
super.onAttach(act);
this.mActivity = act;
/*Initialize whatever you need here*/
}
@Override
public View onCreateView(LayoutInflator inflator, ViewGroup container, Bundle saveInstanceState)
{
View v = inflator.inflate(R.layout.first_fragment, container, false);
Button button = (Button)v.findViewById(R.id.button);
button.setOnClickListener(this);
}
@Override
public void onClick(View v)
{
((OnButtonClickListener), mActivity).loadSecondFragment();
}
public interface OnButtonClickListener
{
void loadSecondFragment();
}
}
您应该能够只是创建第二个片段，并将它在活动加载一个按钮被点击时。
You should be able to just create the second fragment and have it loaded in the activity when a button is clicked.
祝你好运。
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