Question

我在通过共享首选项从两个活动访问String值时遇到问题。我想我会犯一些错误可以帮助我吗？基本上我想从活动1和活动2得到的是使用编辑文本从用户获取整数值，将它们存储在共享首选项中（在应用程序重新启动时恢复）。现在使用活动1和2的值我想在结果活动中执行计算。

我的问题： -

如何在结果活动中访问共享首选项？
值存储在字符串中我可以对其执行计算，还是必须在结果活动中将它们转换为int？如果是，如何将它们转换为int（Integer.valueOff将起作用？）

活动1

public class Abc extends Activity {
    Button one2five, save1;
    EditText edtA, edtB, edtC, edtD, edtE, edtF;
    String tA, tsB, tsC, tsD, tsE, tsF;
    int tB, tC, tD, tE, tF;
    public static String FILE1 = "MyPrefsFile";
    SharedPreferences abcPref;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.abc);
        one2five = (Button) findViewById(R.id.btp1);
        save1 = (Button) findViewById(R.id.btps1);
        edtA = (EditText) findViewById(R.id.etA);
        edtB = (EditText) findViewById(R.id.etB);
        edtC = (EditText) findViewById(R.id.etC);
        edtD = (EditText) findViewById(R.id.etD);
        edtE = (EditText) findViewById(R.id.etE);
        edtF = (EditText) findViewById(R.id.etF);

        abcPref = getSharedPreferences("FILE1", 0);
        edtA.setText(abcPref.getString("tA", ""));
        edtB.setText(abcPref.getString("tsB", ""));
        edtC.setText(abcPref.getString("tsC", ""));
        edtD.setText(abcPref.getString("tsD", ""));
        edtE.setText(abcPref.getString("tsE", ""));
        edtF.setText(abcPref.getString("tsF", ""));

        one2five.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                if ((!edtA.getText().toString().equals(""))
                        && (!edtB.getText().toString().equals(""))
                        && (!edtC.getText().toString().equals(""))
                        && (!edtD.getText().toString().equals(""))
                        && (!edtE.getText().toString().equals(""))
                        && (!edtF.getText().toString().equals(""))) {
                    Intent openg2j = new Intent("com.sports.sport.G2J");
                    startActivity(openg2j);
                }
            }
        });
        save1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                abcPref = getSharedPreferences("FILE1", 0);
                SharedPreferences.Editor editor = abcPref.edit();
                editor.putString("tA", edtA.getText().toString());
                editor.putString("tsB", edtB.getText().toString());
                editor.putString("tsC", edtC.getText().toString());
                editor.putString("tsD", edtD.getText().toString());
                editor.putString("tsE", edtE.getText().toString());
                editor.putString("tsF", edtF.getText().toString());
                editor.commit();
            }
        });
    }
}

活动2

public class G2J extends Activity {
    Button two2five, save2;

    EditText edtG, edtH, edtI, edtJ, edtK;
    int tG, tH, tI, tJ, tK;
    String tsG, tsH, tsI, tsJ, tsK;
    public static String FileP2 = "MyPrefsFile";
    SharedPreferences abcPref;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.g2j);
        two2five = (Button) findViewById(R.id.btp2);
        save2 = (Button) findViewById(R.id.btps2);
        edtG = (EditText) findViewById(R.id.etG);
        edtH = (EditText) findViewById(R.id.etH);
        edtI = (EditText) findViewById(R.id.etI);
        edtJ = (EditText) findViewById(R.id.etJ);
        edtK = (EditText) findViewById(R.id.etK);

        abcPref = getSharedPreferences("FileP2", 0);
        edtG.setText(abcPref.getString("tsG", ""));
        edtH.setText(abcPref.getString("tsH", ""));
        edtI.setText(abcPref.getString("tsI", ""));
        edtJ.setText(abcPref.getString("tsJ", ""));
        edtK.setText(abcPref.getString("tsK", ""));

        two2five.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                if ((!edtG.getText().toString().equals(""))
                        && (!edtH.getText().toString().equals(""))
                        && (!edtI.getText().toString().equals(""))
                        && (!edtJ.getText().toString().equals(""))
                        && (!edtK.getText().toString().equals(""))) {
                    // TODO Auto-generated method stub
                    Intent openl2p = new Intent("com.sports.sport.Results");
                    startActivity(openl2p);
                }
            }
        });
        save2.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                abcPref = G2J.this.getSharedPreferences(FileP2, 0);
                SharedPreferences.Editor editor = abcPref.edit();
                editor.putString("tsG", edtG.getText().toString());
                editor.putString("tsH", edtH.getText().toString());
                editor.putString("tsI", edtI.getText().toString());
                editor.putString("tsJ", edtJ.getText().toString());
                editor.putString("tsK", edtK.getText().toString());
                editor.commit();
            }
        });
    }
}

最后结果活动

public class Results extends Activity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.resultmain);



        SharedPreferences abcPref=  this.getSharedPreferences(FILE1,0);

    }
}

Answer 1

在Abc活动回复中

abcPref = getSharedPreferences("FILE1", 0);

与

 abcPref = getSharedPreferences(FILE1, 0);

在G2J活动回复中

abcPref = getSharedPreferences("FileP2", 0);

与

 abcPref = getSharedPreferences(FileP2, 0);

在Results活动定义

中

public static String FILE1= "MyPrefsFile";

要对字符串值执行caluclation，您可以解析字符串 int value = Integer.parseInt(abcPref.getString("tsG"));等等

如果你只想接受editText中的整数值，那么在你的xcm add：

中

android:inputType="number"

<EditText
android:id="@+id/edtA"
android:inputType="number"
/>

Answer 2

try this way
public class Results extends Activity {


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            setContentView(R.layout.resultmain);
            SharedPreferences abcPref=  this.getSharedPreferences(FILE1,0);



             int a = Integer.parseInt(abcPref.getString("tA", ""));
             int b = Integer.parseInt(abcPref.getString("tsB", ""));
             int c = Integer.parseInt(abcPref.getString("tsC", ""));
             int d = Integer.parseInt(abcPref.getString("tsD", ""));
             int e = Integer.parseInt(abcPref.getString("tsE", ""));
             int f = Integer.parseInt(abcPref.getString("tsF", ""));

          // Your operations



        }
    }

Answer 3

我建议你在两个活动中使用getDefaultSharedPreferences()而不是getSharedPreferences（）。这样就不存在使用首选项文件名称输入拼写错误的风险。

Answer 4

第一，你应该检查空指针异常，如果用户保存它然后你提交编辑器，否则你不保存任何字符串值。因此，如果用户没有将其保存并仍在结果活动中，那么您将从您的偏好中获取字符串，例如abcPref.getString，然后它会抛出NullPointerException。您还可以使用Interger.parseInt(abcPref.getString("tA","" + 0));执行将String解析为Integer等等...

共享偏好在两个或多个活动之间共享

4 个答案: