Question

我遇到了两个问题。

1）如何让我的list.xml显示在listview.xml中？

在我的java类中，我扩展了ListActivity并使用代码：

ListView listView = (ListView)findViewById(R.id.list);
ArrayAdapter<?> arrayAdapter = new ArrayAdapter<?>(this, R.layout.row

我不知道如何完成这个。

2）如何将我保存在sharedPReference上的数据加载到我的行中，这是两个字符串值？

保存两个字符串值的代码是：

String product = "Health Vitamins";
String category = "Nutrition";
savePreference("NAME", product);
savePreference("NUTRITION", category);

然后我在savePreference方法中使用putString（key，value）和commit（）。当我想加载数据时，我只需使用loadPreference（），它将使用getString（“NAME”，“”）和getString（“NUTRITION”，“”）并检索数据。

问题是如何将我检索到的数据实际放入listview row.xml？例如，一旦调用了loadPreference（）方法，就可以检索两个字符串值并将其放在行中？任何想法？

Answer 1

String[] data = //load the array here.  

adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, android.R.id.text1, data);

无论你想把什么放进你的阵列。它可能是您的共享偏好值。但是，为什么你会使用共享偏好，因为它使用键值对。并且你不能在键上加倍意味着你的列表总是有1个或最多2个条目。

Answer 2

您可以使用Intent

从SharedPreferences将数据传递到ListView

公共类MainActivity扩展AppCompatActivity实现了View.OnClickListener {

private EditText nameEditText, rollEditText, deptEditText, semesterEditText;
private Button submittButton;
private TextView textView;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    nameEditText = findViewById(R.id.nameEditTextID);
    rollEditText = findViewById(R.id.rollEditTextID);
    deptEditText = findViewById(R.id.deptEditTextID);
    semesterEditText = findViewById(R.id.semesterEditTextID);
    submittButton = findViewById(R.id.submitButtonID);
    textView = findViewById(R.id.textViewID);


    submittButton.setOnClickListener(this);


}

@Override
public void onClick(View v) {

    if (v.getId() == R.id.submitButtonID) {

        String userName = nameEditText.getText().toString();
        String userRoll = rollEditText.getText().toString();
        String userDept = deptEditText.getText().toString();
        String userSemester = semesterEditText.getText().toString();

        if (userName.equals("") && userRoll.equals("") && userDept.equals("") && userSemester.equals("")) {

            Toast.makeText(getApplicationContext(), "Please enter data", Toast.LENGTH_SHORT).show();

        } else {

            SharedPreferences sharedPreferences = getSharedPreferences("Details", 0);
            //SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

            SharedPreferences.Editor editor = sharedPreferences.edit();

            editor.putString("userNameKey", userName);
            editor.putString("userRollKey", userRoll);
            editor.putString("userDeptKey", userDept);
            editor.putString("userSemesterKey", userSemester);
            editor.apply();
            nameEditText.setText("");
            rollEditText.setText("");
            deptEditText.setText("");
            semesterEditText.setText("");

            Toast.makeText(getApplicationContext(), "Saved successfully", Toast.LENGTH_SHORT).show();

            if (sharedPreferences.contains("userNameKey") && sharedPreferences.contains("userRollKey") && sharedPreferences.contains("userDeptKey")
                    && sharedPreferences.contains("userSemesterKey")) {

                Intent intent = new Intent(MainActivity.this, ListDataActivity.class);
                startActivity(intent);
            }





            /*if (sharedPreferences.contains("userNameKey") && sharedPreferences.contains("userRollKey") && sharedPreferences.contains("userDeptKey")
                    && sharedPreferences.contains("userSemesterKey")) {


                String name = sharedPreferences.getString("userNameKey", "Data not found");
                String roll = sharedPreferences.getString("userRollKey", "Data not found");
                String department = sharedPreferences.getString("userDeptKey", "Data not found");
                String semester = sharedPreferences.getString("userSemesterKey", "Data not found");

                Toast.makeText(getApplicationContext(), "Loaded successfully", Toast.LENGTH_SHORT).show();

                textView.setText(name + "\n" + roll + "\n" + department + "\n" + semester);
            }*/


        }


    }


}

公共类ListDataActivity扩展了AppCompatActivity {

private ListView listView;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list_data);

    listView = findViewById(R.id.listViewID);


    SharedPreferences sharedPreferences = getSharedPreferences("Details", 0);
    String name = sharedPreferences.getString("userNameKey", "Data not found");
    String roll = sharedPreferences.getString("userRollKey", "Data not found");
    String department = sharedPreferences.getString("userDeptKey", "Data not found");
    String semester = sharedPreferences.getString("userSemesterKey", "Data not found");

   Toast.makeText(this, "Roll is:" + roll, Toast.LENGTH_SHORT).show();




    ArrayList<String> arrayList = new ArrayList<>();
    arrayList.add(name);
    arrayList.add(roll);
    arrayList.add(department);
    arrayList.add(semester);
    ArrayAdapter<String>arrayAdapter = new ArrayAdapter<String>(this,R.layout.list_item,R.id.sampleTextViewID,arrayList);
    listView.setAdapter(arrayAdapter);




}

}

如何将数据从sharedPreference加载到ListView行？

2 个答案: