保存ArrayList至SharedPreferences
其中ArrayList中每个元素为String：
ListenvironmentList = new ArrayList();
SharedPreferences.Editor editor = getSharedPreferences("EnvironDataList", MODE_PRIVATE).edit();
editor.putInt("EnvironNums", environmentList.size());
for (int i = 0; i < environmentList.size(); i++)
{ editor.putString("item_"+i, environmentList.get(i));
}
editor.commit();
对应的取出操作为：
ListenvironmentList = new ArrayList();
SharedPreferences preferDataList = getSharedPreferences("EnvironDataList", MODE_PRIVATE);
int environNums = preferDataList.getInt("EnvironNums", 0);
for (int i = 0; i < environNums; i++)
{
String environItem = preferDataList.getString("item_"+i, null);
environmentList.add(environItem);
}
保存ArrayList至SharedPreferences，其中list的每个元素为自定义对象
1 首先将自定义对象序列化
public class CoordinateAlterSample implements Serializable {
private double x;
private double y;
private String name;
public double getX() {
return x;
}
public void setX(double x) {
this.x = x;
}
public double getY() {
return y;
}
public void setY(double y) {
this.y = y;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
其次，将list转为json，即可保存到SharedPreferences中：
ListalterSamples = new ArrayList();
SharedPreferences.Editor editor = getSharedPreferences("AlterSamplesList", MODE_PRIVATE).edit();
Gson gson = new Gson();
String json = gson.toJson(alterSamples);
Log.d(TAG, "saved json is "+ json);
editor.putString("alterSampleJson", json);
editor.commit();
对应的取出操作为：
SharedPreferences preferences=getSharedPreferences("AlterSamplesList", MODE_PRIVATE);
Stringjson=preferences.getString("alterSampleJson",null);
if(json!=null){
Gson gson=newGson();Typetype=newTypeToken>(){}.
getType();
ListalterSamples=newArrayList();
alterSamples=gson.fromJson(json,type);
for(int i=0; i
{Log.d(TAG, alterSamples.get(i).getName()+":"+alterSamples.get(i).getX()+","+alterSamples.get(i).getY());
}
}