Android 提交时未将数据保存在共享首选项中
我试图将片段接收到的数据保存到共享首选项中,以便在重新创建相同片段时可以重用存储在共享首选项中的数据。但不知何故,数据并没有得到保存,而preference的默认值被返回到我的片段中。 下面是代码。 实现共享偏好的片段Android 提交时未将数据保存在共享首选项中,android,android-fragments,sharedpreferences,storage,android-preferences,Android,Android Fragments,Sharedpreferences,Storage,Android Preferences,我试图将片段接收到的数据保存到共享首选项中,以便在重新创建相同片段时可以重用存储在共享首选项中的数据。但不知何故,数据并没有得到保存,而preference的默认值被返回到我的片段中。 下面是代码。 实现共享偏好的片段 提前谢谢 而不是streamUrl=playerSettings.getString(streamUrl,“未找到链接”) 你应该使用 streamUrl = playerSettings.getString("streamLink","No Link Found"); 也可以
提前谢谢 而不是
streamUrl=playerSettings.getString(streamUrl,“未找到链接”)代码>
你应该使用
streamUrl = playerSettings.getString("streamLink","No Link Found");
也可以使用apply代替commit代替streamUrl=playerSettings.getString(streamUrl,“未找到链接”)代码>
你应该使用
streamUrl = playerSettings.getString("streamLink","No Link Found");
也可以使用apply而不是commit您使用的是两个SharedReferences播放器设置;一个全局,一个在onCreate中,您使用的是未初始化的上一个
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
public class StreamFragment extends Fragment {
public String streamUrl=null;
TextView textView;
public static final String playerData="pData";
SharedPreferences playerSettings;
public StreamFragment(){};
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString("streamLink","No Link Found");
}
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stream, container, false);
playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString("streamLink","No Link Found");
//getData();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
return view;
}
public void getUrl(String data)
{
streamUrl=data;
playerSettings = this.getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = playerSettings.edit();
editor.putString("streamLink", streamUrl);
editor.commit();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
}
}
您正在使用两个SharedReferences播放器设置;一个全局,一个在onCreate中,您使用的是未初始化的上一个
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
public class StreamFragment extends Fragment {
public String streamUrl=null;
TextView textView;
public static final String playerData="pData";
SharedPreferences playerSettings;
public StreamFragment(){};
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString("streamLink","No Link Found");
}
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stream, container, false);
playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString("streamLink","No Link Found");
//getData();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
return view;
}
public void getUrl(String data)
{
streamUrl=data;
playerSettings = this.getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = playerSettings.edit();
editor.putString("streamLink", streamUrl);
editor.commit();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
}
}
首选项值的键不正确。请注意下面的一行
streamUrl = playerSettings.getString(streamUrl,"No Link Found");
使用一些常量值作为键
private static final String STREAM_URL = "stream_url";
并使用常数作为键,如下所述
streamUrl = playerSettings.getString(STREAM_URL,"No Link Found");
首选项值的键不正确。请注意下面的一行
streamUrl = playerSettings.getString(streamUrl,"No Link Found");
使用一些常量值作为键
private static final String STREAM_URL = "stream_url";
并使用常数作为键,如下所述
streamUrl = playerSettings.getString(STREAM_URL,"No Link Found");
我试图在这里解释这一点:
请参阅此图:
如您所见,onCreate
在onCreateview
之前启动
让我们分析您的代码:
public class StreamFragment extends Fragment {
public String streamUrl=null;
TextView textView;
public static final String playerData="pData";
SharedPreferences playerSettings;
public StreamFragment(){};
在这里,您的streamUrl
是null
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
/*SharedPreferences -- no needed*/playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString(/*streamUrl -- replace with a key value*/,"No Link Found");
}
这是第一个被激发的方法。这里您试图从SharedRef
获取一个字符串,该字符串应命名为null
。这一点是错误的。getString
上的第一个参数应该是一个键,并且对于相同的值,在任何地方都应该是唯一的
另一件事是,您正在使用相同的名称显示另一个istance ofSharedReferences
,因此请删除IStantation中的强制转换
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stream, container, false);
//playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE); -- they are already istantiated
streamUrl = playerSettings.getString(/*streamUrl -- replace with a key value*/,"No Link Found");
//getData();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
return view;
}
现在,您正在将streamUrl
设置为SharedReferences的
值,该值使用相同的变量streamUrl
命名。这意味着:
streamUrl /*which is currently null*/ = playerSettings.getString(null, "No Link Found");
您仍应将键
从streamUrl
替换为静态唯一字段
public void getUrl(String data)
{
streamUrl=data;
//playerSettings = this.getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE); -- already done above
SharedPreferences.Editor editor = playerSettings.edit();
editor.putString("streamLink", streamUrl);
//editor.commit(); --replace with apply
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
}
}
这应该是保存值的点,因此上面使用的键应该是“streamLink”
将提交替换为应用并删除IStation,因为它已完成
现在。。说它应该是这样的:
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
public class StreamFragment extends Fragment {
public String streamUrl=null;
TextView textView;
public static final String playerData="pData";
public static final String valueKey="streamLink";
SharedPreferences playerSettings;
public StreamFragment(){};
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString(valueKey,"No Link Found");
}
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stream, container, false);
streamUrl = playerSettings.getString(valueKey,"No Link Found");
//getData();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
return view;
}
public void getUrl(String data)
{
streamUrl=data;
SharedPreferences.Editor editor = playerSettings.edit();
editor.putString(valueKey, streamUrl);
editor.apply();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
}
}
希望这能对你有所帮助。我试着在这里解释一下这一点:
请参阅此图:
如您所见,onCreate
在onCreateview
之前启动
让我们分析您的代码:
public class StreamFragment extends Fragment {
public String streamUrl=null;
TextView textView;
public static final String playerData="pData";
SharedPreferences playerSettings;
public StreamFragment(){};
在这里,您的streamUrl
是null
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
/*SharedPreferences -- no needed*/playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString(/*streamUrl -- replace with a key value*/,"No Link Found");
}
这是第一个被激发的方法。这里您试图从SharedRef
获取一个字符串,该字符串应命名为null
。这一点是错误的。getString
上的第一个参数应该是一个键,并且对于相同的值,在任何地方都应该是唯一的
另一件事是,您正在使用相同的名称显示另一个istance ofSharedReferences
,因此请删除IStantation中的强制转换
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stream, container, false);
//playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE); -- they are already istantiated
streamUrl = playerSettings.getString(/*streamUrl -- replace with a key value*/,"No Link Found");
//getData();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
return view;
}
现在,您正在将streamUrl
设置为SharedReferences的
值,该值使用相同的变量streamUrl
命名。这意味着:
streamUrl /*which is currently null*/ = playerSettings.getString(null, "No Link Found");
您仍应将键
从streamUrl
替换为静态唯一字段
public void getUrl(String data)
{
streamUrl=data;
//playerSettings = this.getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE); -- already done above
SharedPreferences.Editor editor = playerSettings.edit();
editor.putString("streamLink", streamUrl);
//editor.commit(); --replace with apply
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
}
}
这应该是保存值的点,因此上面使用的键应该是“streamLink”
将提交替换为应用并删除IStation,因为它已完成
现在。。说它应该是这样的:
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
public class StreamFragment extends Fragment {
public String streamUrl=null;
TextView textView;
public static final String playerData="pData";
public static final String valueKey="streamLink";
SharedPreferences playerSettings;
public StreamFragment(){};
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
playerSettings = getActivity().getSharedPreferences(playerData, Context.MODE_PRIVATE);
streamUrl = playerSettings.getString(valueKey,"No Link Found");
}
@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_stream, container, false);
streamUrl = playerSettings.getString(valueKey,"No Link Found");
//getData();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
return view;
}
public void getUrl(String data)
{
streamUrl=data;
SharedPreferences.Editor editor = playerSettings.edit();
editor.putString(valueKey, streamUrl);
editor.apply();
Toast.makeText(getActivity(),"Stream Saved"+streamUrl,Toast.LENGTH_LONG).show();
}
}
希望这能对您有所帮助。您的getUrl(String)
方法未调用。因此您的共享首选项值未存储,在playerSettings.getString(streamUrl,“未找到链接”)之前调用它代码>
此外,您还创建了两次“SharedReferences”实例,从onCreateView
中删除。请使用editor.apply()
而不是editor.commit()
您的getUrl(String)
方法未调用。因此您的共享首选项值未存储,在playerSettings.getString(streamUrl,“未找到链接”)之前调用它代码>
此外,您还创建了两次“SharedReferences”实例,从onCreateView
中删除。使用editor.apply()
而不是editor.commit()
editor.commit();不推荐使用use editor.apply();您再次在oncreate方法中创建实例。只需在onCreate方法中重新调用“SharedReferences”。@Jadavlat听说apply不会发送成功结果您在哪里调用getUrl()
方法?@VivekMishra使用interfaceeditor.commit()调用片段;不推荐使用use editor.apply();您再次在oncreate方法中创建实例。只需在onCreate方法中重新调用“SharedReferences”。@Jadavlat听说apply不发送成功结果您在哪里调用getUrl()
方法?@VivekMishra使用接口调用片段但我读到commit返回成功结果,而apply wontYes,commit返回成功结果。但是apply的优点是它是异步的。为什么不使用androidstudio建议您使用的东西,而不是您已经使用过的东西呢?应用是正确的解决方案。提交正在工作。。。然而,@santosh解决了主要问题,但我读到commit返回成功结果,而Apply wontYes,commit返回成功。但是apply的优点是它是异步的,为什么不使用androidstudio建议您使用的东西呢