Android儲存ArrayList至SharedPreferences

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儲存ArrayList至SharedPreferences
其中ArrayList中每個元素為String

List<String> environmentList = new ArrayList<String>();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();

 

對應的取出操作為：

List<String> environmentList = new ArrayList<String>();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);}

 

儲存ArrayList至SharedPreferences，其中list的每個元素為自訂對象
1 首先將自訂對象序列化

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，將list轉為json，即可儲存到SharedPreferences中

List<CoordinateAlterSample> alterSamples = new ArrayList<CoordinateAlterSample>();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();

 

對應的取出操作為：

SharedPreferences preferences = getSharedPreferences("AlterSamplesList", MODE_PRIVATE);String json = preferences.getString("alterSampleJson", null);if (json != null){    Gson gson = new Gson();    Type type = new TypeToken<List<CoordinateAlterSample>>(){}.getType();    List<CoordinateAlterSample> alterSamples = new ArrayList<CoordinateAlterSample>();    alterSamples = gson.fromJson(json, type);    for(int i = 0; i < alterSamples.size(); i++)    {        Log.d(TAG, alterSamples.get(i).getName()+":" + alterSamples.get(i).getX() + "," + alterSamples.get(i).getY());    }}

Android儲存ArrayList至SharedPreferences