我在framelayout中附加了一个片段......我正在获取片段的子视图 使用framelayout。
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pan);
CardFragment fragment=new CardFragment();
FragmentManager fm=getSupportFragmentManager();
FragmentTransaction ft=fm.beginTransaction();
ft.add(R.id.container, fragment);
container=(FrameLayout)findViewById(R.id.container);
img_pan=(ImageView)container.findViewById(R.id.img_pan);
txt_name=(TextView)container.findViewById(R.id.txt_name);
txt_father=(TextView)container.findViewById(R.id.txt_father);
txt_dob=(TextView)container.findViewById(R.id.txt_dob);
txt_type=(TextView)container.findViewById(R.id.txt_type);
txt_panid=(TextView)container.findViewById(R.id.txt_panid);
}
@Override
public void onResume()
{
super.onResume();
Intent i=getIntent();
String name=i.getStringExtra("pan_name");
String father=i.getStringExtra("pan_father");
String dob=i.getStringExtra("pan_dob");
String type=i.getStringExtra("pan_type");
String panid=i.getStringExtra("pan_id");
filePath=i.getStringExtra("pan_filePath");
Log.d("CardActivity", "Filepath: "+filePath);
Bitmap bmp=BitmapFactory.decodeFile(filePath);
if(bmp==null)
{
Log.d("CardActivity", "Error getting image to bitmap");
}
img_pan.setImageBitmap(bmp);
txt_name.setText(name);
txt_father.setText(father);
txt_dob.setText(dob);
txt_type.setText(type);
txt_panid.setText(panid);
}
当我尝试向视图添加值时，它会抛出NullPointerException
编辑：在将所有内容分成碎片之前，它工作得很好。EDIT2：我已根据建议更改了活动和片段，活动onCreate：
Bundle state=new Bundle();
state.putString("pan_name", name);
state.putString("pan_father", father);
state.putString("pan_dob", dob);
state.putString("pan_type",type);
state.putString("pan_id", panid);
state.putString("pan_filepath", filePath);
CardFragment fragment=new CardFragment();
fragment.setArguments(state);
FragmentManager fm=getSupportFragmentManager();
FragmentTransaction ft=fm.beginTransaction();
ft.add(R.id.container, fragment);
ft.commit();
if(fm.executePendingTransactions())
{
Log.d("CardActivity", "Executed all pending operations");
}
片段onCreateView方法：
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState)
{
super.onCreateView(inflater, container, savedInstanceState);
img_pan=(ImageView)container.findViewById(R.id.img_pan);
txt_name=(TextView)container.findViewById(R.id.txt_name);
txt_father=(TextView)container.findViewById(R.id.txt_father);
txt_dob=(TextView)container.findViewById(R.id.txt_dob);
txt_type=(TextView)container.findViewById(R.id.txt_type);
txt_panid=(TextView)container.findViewById(R.id.txt_panid);
Bundle bundle=getArguments();
String name=bundle.getString("pan_name");//line 39
String father=bundle.getString("pan_father");
String dob=bundle.getString("pan_dob");
String type=bundle.getString("pan_type");
String id=bundle.getString("pan_id");
String filePath=bundle.getString("pan_filepath");
Bitmap bmp=BitmapFactory.decodeFile(filePath);
img_pan.setImageBitmap(bmp);
txt_name.setText(name);
txt_father.setText(father);
txt_dob.setText(dob);
txt_type.setText(type);
txt_panid.setText(id);
return inflater.inflate(R.layout.layout_pan, container,false);
}
现在它仍然返回一个NullPointerException，logcat似乎指向了getArguments（）。我尝试使用saveInstanceState但没有成功。
E/AndroidRuntime(13367): Caused by: java.lang.NullPointerException
E/AndroidRuntime(13367): at com.example.newscancardapp.CardFragment.onCreateView(CardFragment.java:39)
E/AndroidRuntime(13367): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1478)
E/AndroidRuntime(13367): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
E/AndroidRuntime(13367): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
E/AndroidRuntime(13367): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1086)
E/AndroidRuntime(13367): at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1877)
E/AndroidRuntime(13367): at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:552)
E/AndroidRuntime(13367): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1133)
E/AndroidRuntime(13367): at android.app.Activity.performStart(Activity.java:4529)
E/AndroidRuntime(13367): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1929)
编辑3此代码正常运行：
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState)
{
super.onCreateView(inflater, container, savedInstanceState);
View pan_layout=inflater.inflate(R.layout.layout_card, container,false);
img_pan=(ImageView)pan_layout.findViewById(R.id.img_pan);
txt_name=(TextView)pan_layout.findViewById(R.id.txt_name);
txt_father=(TextView)pan_layout.findViewById(R.id.txt_father);
txt_dob=(TextView)pan_layout.findViewById(R.id.txt_dob);
txt_panid=(TextView)pan_layout.findViewById(R.id.txt_panid);
Bundle bundle=getArguments();
String name=bundle.getString("name");
String father=bundle.getString("father");
String dob=bundle.getString("dob");
String id=bundle.getString("id");
//String filePath=bundle.getString("filepath");
//Bitmap bmp=BitmapFactory.decodeFile(filePath);
//img_pan.setImageBitmap(bmp);
txt_name.setText(name);
txt_father.setText(father);
txt_dob.setText(dob);
txt_panid.setText(id);
return pan_layout;
}
将代码重构为单独的应用程序以进行测试...我已禁用filePath。 感谢Luksprog的回答。
答案 0 :(得分：1)
我在一个framelayout中附上了一个片段......我得到了 使用framelayout创建片段的子视图。
首先，为了将片段实际绑定到活动，您需要在commit()上调用FragmentTransaction方法。
即使你这样做，你的代码仍会失败，因为片段事务是异步的，当你调用commit()时它不会发生，它将在以后当主UI线程完成当前时安排信息。要解决此问题，您可以在提交后使用的executePendingTransactions()上调用FragmentManager（但这不是正确的路线）。
您不应该尝试直接使用片段的视图。当您尝试初始化片段的视图时，应该通过在实例化时将数据作为参数传递给片段的Bundle或通过使片段直接从活动中检索它来完成（在其中一个回调中使用getActivity()并将其投射到您的活动中）（例如onCreateView()）。