轉自:http://blog.csdn.net/yangzhaomuma/article/details/50718191
在使用SharedPreferences的時候,大家都可以看到它有幾個讀寫的標誌位,比如 PRIVATE、READABLE、WRITEABLE等。
在使用SharedPreferences進行進程數據共享時,我們發現,有些雖然過時了,但是實際上還是可以用的。
只是Google不建議大家這麼幹了。所以這篇文章只是一個介紹實現,科普。
怎麼實現呢?
先新建兩個Android工程,分別命名爲:ShareprefenceShareA(後文稱爲A)、ShareprefenceShareB(後文稱爲B)。
我們想要實現的目標是,在A中寫入到Shareprefence中的內容,在B中可以讀到。
先貼出A中代碼:
- package com.example.shareprefencesharea;
- import android.os.Bundle;
- import android.app.Activity;
- import android.view.Menu;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.EditText;
- import android.widget.Toast;
- public class MainActivity extends Activity {
- Button btn,btn1;
- EditText editText;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- btn=(Button)findViewById(R.id.btn);
- btn1=(Button)findViewById(R.id.btn1);
- editText=(EditText)findViewById(R.id.text);
- final SharedPrefencesImp imp=new SharedPrefencesImp(MainActivity.this);
- btn.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- // TODO Auto-generated method stub
- imp.SetSharedPrefences("info", editText.getText().toString());
- }
- });
- btn1.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- // TODO Auto-generated method stub
- String result= imp.GetSharedPrefences("info");
- Toast.makeText(getApplicationContext(), result, 0).show();
- }
- });
- }
- }
package com.example.shareprefencesharea;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
Button btn,btn1;
EditText editText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn=(Button)findViewById(R.id.btn);
btn1=(Button)findViewById(R.id.btn1);
editText=(EditText)findViewById(R.id.text);
final SharedPrefencesImp imp=new SharedPrefencesImp(MainActivity.this);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
imp.SetSharedPrefences("info", editText.getText().toString());
}
});
btn1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String result= imp.GetSharedPrefences("info");
Toast.makeText(getApplicationContext(), result, 0).show();
}
});
}
}
以上代碼做的是set、get操作。
以下是SharedPrefencesImp的代碼:
- package com.example.shareprefencesharea;
- import android.content.Context;
- import android.content.SharedPreferences;
- public class SharedPrefencesImp {
- private Context context;
- private String settingString="SharedPrefencesXml";
- public SharedPrefencesImp(Context context)
- {
- this.context=context;
- }
- /**
- * 設置sharedprefences
- * @param keyname
- * @param keyvalue
- */
- public void SetSharedPrefences(String keyname,String keyvalue)
- {
- //SharedPreferences.Editor editor=PreferenceManager.getDefaultSharedPreferences(context).edit();寫法也可以如此,默認名稱爲包名
- SharedPreferences.Editor editor=context.getSharedPreferences(settingString, Context.MODE_WORLD_READABLE).edit();
- editor.putString(keyname, keyvalue);
- editor.commit();
- }
- /**
- * 獲取sharedprefences中key爲keyname的值
- * @param keyname
- * @return
- */
- public String GetSharedPrefences(String keyname)
- {
- SharedPreferences sharedPreferences=context.getSharedPreferences(settingString, Context.MODE_WORLD_READABLE);
- String resultString= sharedPreferences.getString(keyname, "");
- return resultString;
- }
- }
package com.example.shareprefencesharea;
import android.content.Context;
import android.content.SharedPreferences;
public class SharedPrefencesImp {
private Context context;
private String settingString="SharedPrefencesXml";
public SharedPrefencesImp(Context context)
{
this.context=context;
}
/**
* 設置sharedprefences
* @param keyname
* @param keyvalue
*/
public void SetSharedPrefences(String keyname,String keyvalue)
{
//SharedPreferences.Editor editor=PreferenceManager.getDefaultSharedPreferences(context).edit();寫法也可以如此,默認名稱爲包名
SharedPreferences.Editor editor=context.getSharedPreferences(settingString, Context.MODE_WORLD_READABLE).edit();
editor.putString(keyname, keyvalue);
editor.commit();
}
/**
* 獲取sharedprefences中key爲keyname的值
* @param keyname
* @return
*/
public String GetSharedPrefences(String keyname)
{
SharedPreferences sharedPreferences=context.getSharedPreferences(settingString, Context.MODE_WORLD_READABLE);
String resultString= sharedPreferences.getString(keyname, "");
return resultString;
}
}
與傳統的本進程中使用的shareprefence不同的地方在於,我們使用了MODE_WORLD_READABLE(傳統本進程使用,一般使用MODE_PRIVATE):
- SharedPreferences.Editor editor=context.getSharedPreferences(settingString, Context.MODE_WORLD_READABLE).edit();
SharedPreferences.Editor editor=context.getSharedPreferences(settingString, Context.MODE_WORLD_READABLE).edit();
B的主程序代碼如下:
- package com.example.shareprefenceshareb;
- import android.os.Bundle;
- import android.app.Activity;
- import android.content.Context;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.EditText;
- import android.widget.Toast;
- public class MainActivity extends Activity {
- Button btn,btn1;
- EditText editText;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- btn=(Button)findViewById(R.id.btn);
- btn1=(Button)findViewById(R.id.btn1);
- editText=(EditText)findViewById(R.id.text);
- Context c=null;
- try {
- //com.example.shareprefencesharea 是A的包名
- //Context.CONTEXT_IGNORE_SECURITY 忽略安全檢查標誌
- c = createPackageContext("com.example.shareprefencesharea", Context.CONTEXT_IGNORE_SECURITY);
- } catch (SecurityException e) {
- e.printStackTrace();
- } catch (Exception e) {
- e.printStackTrace();
- }
- final SharedPrefencesImp imp=new SharedPrefencesImp(c);
- btn1.setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- // TODO Auto-generated method stub
- String result= imp.GetSharedPrefences("info");
- Toast.makeText(MainActivity.this, result, 0).show();
- }
- });
- }
- }
package com.example.shareprefenceshareb;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
Button btn,btn1;
EditText editText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn=(Button)findViewById(R.id.btn);
btn1=(Button)findViewById(R.id.btn1);
editText=(EditText)findViewById(R.id.text);
Context c=null;
try {
//com.example.shareprefencesharea 是A的包名
//Context.CONTEXT_IGNORE_SECURITY 忽略安全檢查標誌
c = createPackageContext("com.example.shareprefencesharea", Context.CONTEXT_IGNORE_SECURITY);
} catch (SecurityException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
final SharedPrefencesImp imp=new SharedPrefencesImp(c);
btn1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String result= imp.GetSharedPrefences("info");
Toast.makeText(MainActivity.this, result, 0).show();
}
});
}
}
重點在做了註釋的這一行。
SharePrefencesImp的代碼如下:
- package com.example.shareprefenceshareb;
- import android.content.Context;
- import android.content.SharedPreferences;
- import android.content.pm.PackageManager.NameNotFoundException;
- public class SharedPrefencesImp {
- private Context context;
- private String settingString="SharedPrefencesXml";
- public SharedPrefencesImp(Context context)
- {
- this.context=context;
- }
- /**
- * 獲取sharedprefences中key爲keyname的值
- * @param keyname
- * @return
- */
- public String GetSharedPrefences(String keyname)
- {
- SharedPreferences sharedPreferences=context.getSharedPreferences(settingString, context.MODE_PRIVATE);
- String resultString= sharedPreferences.getString(keyname, "");
- return resultString;
- }
- }
package com.example.shareprefenceshareb;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.pm.PackageManager.NameNotFoundException;
public class SharedPrefencesImp {
private Context context;
private String settingString="SharedPrefencesXml";
public SharedPrefencesImp(Context context)
{
this.context=context;
}
/**
* 獲取sharedprefences中key爲keyname的值
* @param keyname
* @return
*/
public String GetSharedPrefences(String keyname)
{
SharedPreferences sharedPreferences=context.getSharedPreferences(settingString, context.MODE_PRIVATE);
String resultString= sharedPreferences.getString(keyname, "");
return resultString;
}
}
綜上,我們可以看到,進程間共用shareprefence是可以實現的。只是有個特別的地方,需要把第一個app的包名對應的context傳入到第二個app中,否則是取不到數據的。
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