我只是在尝试构建一个使用片段的简单示例应用程序。我的场景是,我有两个活动,每个活动中都有一个片段。第一个片段有一个edittext和一个按钮。第二个片段有一个文本视图。当我在edittext中输入一个名称并单击按钮时,第二个片段中的文本视图应该显示在第一个片段的edittext中输入的名称。
我能够将值从第一个片段发送到它的活动,然后从该活动发送到第二个活动。现在我如何在第二个片段中使用这个值呢?
下面是Java代码:
package com.example.fragmentexample;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class Fragment_1 extends Fragment{
OnFragmentChangedListener mCallback;
// Container Activity must implement this interface
public interface OnFragmentChangedListener {
public void onButtonClicked(String name);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
mCallback = (OnFragmentChangedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnHeadlineSelectedListener");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View view = inflater.inflate(R.layout.fragment_fragment_1, container, false);
final EditText edtxtPersonName_Fragment = (EditText) view.findViewById(R.id.edtxtPersonName);
Button btnSayHi_Fragment = (Button) view.findViewById(R.id.btnSayHi);
btnSayHi_Fragment.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String name = edtxtPersonName_Fragment.getText().toString();
FragmentManager fm = getFragmentManager();
Fragment_2 f2 = (Fragment_2) fm.findFragmentById(R.id.fragment_content_2);
Activity activity = getActivity();
if(activity != null)
{
Toast.makeText(activity, "Say&ing Hi in Progress...", Toast.LENGTH_LONG).show();
}
if(f2 != null && f2.isInLayout())
{
f2.setName(name);
}
else
{
mCallback.onButtonClicked(name);
}
}
});
return view;
}
}
文件MainActivity.Java
package com.example.fragmentexample;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Choreographer.FrameCallback;
import android.view.Menu;
public class MainActivity extends Activity implements Fragment_1.OnFragmentChangedListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
@Override
public void onButtonClicked(String name) {
// TODO Auto-generated method stub
Intent i = new Intent(this, SecondActivity.class);
i.putExtra("", name);
startActivity(i);
}
}
文件SecondActivity.Java
package com.example.fragmentexample;
import android.app.Activity;
import android.os.Bundle;
public class SecondActivity extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Bundle b = getIntent().getExtras();
Fragment_2 f2 = new Fragment_2();
f2.setArguments(b);
}
}
Fragment_2.Java
package com.example.fragmentexample;
import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class Fragment_2 extends Fragment{
View view;
TextView txtName;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
view = inflater.inflate(R.layout.fragment_fragment_2, container, false);
// Exception at this line
String name = getArguments().getString("message");
txtName = (TextView) view.findViewById(R.id.txtViewResult);
txtName.setText(name);
return view;
}
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
}
public void setName(String name)
{
txtName.setText("Hi " + name);
}
}
我得到了以下异常:
04-16 18:10:24.573: E/AndroidRuntime(713): FATAL EXCEPTION: main
04-16 18:10:24.573: E/AndroidRuntime(713): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.fragmentexample/com.example.fragmentexample.SecondActivity}: android.view.InflateException: Binary XML file line #8: Error inflating class fragment
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.ActivityThread.access$500(ActivityThread.java:122)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.os.Handler.dispatchMessage(Handler.java:99)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.os.Looper.loop(Looper.java:132)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.ActivityThread.main(ActivityThread.java:4123)
04-16 18:10:24.573: E/AndroidRuntime(713): at java.lang.reflect.Method.invokeNative(Native Method)
04-16 18:10:24.573: E/AndroidRuntime(713): at java.lang.reflect.Method.invoke(Method.java:491)
04-16 18:10:24.573: E/AndroidRuntime(713): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
04-16 18:10:24.573: E/AndroidRuntime(713): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
04-16 18:10:24.573: E/AndroidRuntime(713): at dalvik.system.NativeStart.main(Native Method)
04-16 18:10:24.573: E/AndroidRuntime(713): Caused by: android.view.InflateException: Binary XML file line #8: Error inflating class fragment
04-16 18:10:24.573: E/AndroidRuntime(713): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:688)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.view.LayoutInflater.rInflate(LayoutInflater.java:724)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.view.LayoutInflater.inflate(LayoutInflater.java:479)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.view.LayoutInflater.inflate(LayoutInflater.java:391)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.view.LayoutInflater.inflate(LayoutInflater.java:347)
04-16 18:10:24.573: E/AndroidRuntime(713): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:223)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.Activity.setContentView(Activity.java:1786)
04-16 18:10:24.573: E/AndroidRuntime(713): at com.example.fragmentexample.SecondActivity.onCreate(SecondActivity.java:13)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.Activity.performCreate(Activity.java:4397)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1048)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)
04-16 18:10:24.573: E/AndroidRuntime(713): ... 11 more
04-16 18:10:24.573: E/AndroidRuntime(713): Caused by: java.lang.NullPointerException
04-16 18:10:24.573: E/AndroidRuntime(713): at com.example.fragmentexample.Fragment_2.onCreateView(Fragment_2.java:24)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:754)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:956)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.FragmentManagerImpl.addFragment(FragmentManager.java:1035)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.app.Activity.onCreateView(Activity.java:4177)
04-16 18:10:24.573: E/AndroidRuntime(713): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:664)
04-16 18:10:24.573: E/AndroidRuntime(713): ... 21 more
如何将值从SecondActivity.java中的捆绑包获取到Fragment_2.Java文件?
发布于 2016-12-03 22:48:37
//在Fragment_1.java中
Bundle bundle = new Bundle();
bundle.putString("key","abc"); // Put anything what you want
Fragment_2 fragment2 = new Fragment_2();
fragment2.setArguments(bundle);
getFragmentManager()
.beginTransaction()
.replace(R.id.content, fragment2)
.commit();
//在Fragment_2.java中
Bundle bundle = this.getArguments();
if(bundle != null){
// handle your code here.
}
希望这能对你有所帮助。
发布于 2018-08-19 12:02:49
在片段之间传递数据的最新解决方案可以通过使用ViewModel和LiveData等安卓架构组件来实现。使用此解决方案,您不需要定义通信接口,并且可以获得使用视图模型的优势,如由于配置更改而导致的数据生存。
在此解决方案中,通信中涉及的片段共享相同的视图模型对象,该对象绑定到它们的活动生命周期。视图模型对象包含livedata对象。一个片段设置要在livedata对象上传递的数据,第二个片段观察器livedata更改并接收数据。
下面是完整的示例:
发布于 2020-08-27 17:01:46
特别是现在Android团队正在推动更多地坚持单一活动模型,片段之间的通信变得更加重要。
在接收方片段中,添加一个监听器:
setFragmentResultListener(
"data_request_key",
lifecycleOwner,
FragmentResultListener { requestKey: String, bundle: Bundle ->
// Unpack the bundle and use data
val frag1Str = bundle.getString("frag1_data_key")
})
在发件人片段(Frag1)中:
setFragmentResult(
"data_request_key",
bundleOf("frag1_data_key" to value)
)
请记住,此功能仅在fragment-ktx版本1.3.0-alpha04及更高版本中可用。
学分和进一步阅读:
https://stackoverflow.com/questions/16036572
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