java - 如何让我的 android 应用程序将 SharedPreferences 作为一组首选项，以便我可以控制它并使用按钮清除首选项

Question

我试图拥有一次 SharedPreferences 并将其控制为不同的方法，而不是在不同的方法中使用不同的 SharedPreferences。我在 onCreate、LoadPreferences、SavePreferences 和 ClearTextViews 方法中有 SharedPreferences。我想这样做，以便我将首选项从 EditText 中输入的文本保存到 TextViews，然后能够使用按钮将它们全部清除。如果可以，请你帮助我。以下是相关代码：

公共类 notesActivity 扩展 Activity 实现 OnClickListener {

Button saveNote;
Button clearText;
EditText note;
TextView textSavedNote1, textSavedNote2, textSavedNote3, textSavedNote4, textSavedNote5, textSavedNote6;
SharedPreferences spNote;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_notes);

    saveNote = (Button)this.findViewById(R.id.saveNotes);
    saveNote.setOnClickListener(this);

    clearText = (Button)this.findViewById(R.id.clearAllText);
    clearText.setOnClickListener(this);

    textSavedNote1 = (TextView)findViewById(R.id.stringSavedNote1);
    textSavedNote2 = (TextView)findViewById(R.id.stringSavedNote2);
    textSavedNote3 = (TextView)findViewById(R.id.stringSavedNote3);
    textSavedNote4 = (TextView)findViewById(R.id.stringSavedNote4);
    textSavedNote5 = (TextView)findViewById(R.id.stringSavedNote5);
    textSavedNote6 = (TextView)findViewById(R.id.stringSavedNote6);

    note = (EditText)this.findViewById(R.id.notes);

    spNote = PreferenceManager.getDefaultSharedPreferences(this);
    SharedPreferences.Editor edit = spNote.edit();
    edit.putString("note"+saveNote,note.getText().toString());
    edit.commit();
}



public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    // Goes back to the home screen
    case R.id.item1:  Intent i = new Intent(notesActivity.this, UserSettingActivity.class);
    startActivity(i);

    case R.id.item2:
            Intent intent = new Intent(this, MainActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
            return true;
    // Refreshes the page.   
    case R.id.item3:
            finish();
            startActivity(getIntent());
        default:
            return super.onOptionsItemSelected(item);
    }
}


public void onClick (View v){
    if(v==saveNote){
        SavePreferences("NOTE1", note.getText().toString());
        LoadPreferences();
        note.setText("");
        if(textSavedNote1.getText().toString().length()>0){
            SavePreferences("NOTE2", note.getText().toString());
            LoadPreferences();
            note.setText("");
        }
        else{
    }
}
    else if(v==clearText){
        ClearTextViews();
    }
}

private void SavePreferences(String key, String value){
    SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(key, value);
    editor.commit();
   }

private void LoadPreferences(){
    SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
    String strSavedNote1 = sharedPreferences.getString("NOTE1", "");
    String strSavedNote2 = sharedPreferences.getString("NOTE2", "");
    String strSavedNote3 = sharedPreferences.getString("NOTE3", "");
    String strSavedNote4 = sharedPreferences.getString("NOTE4", "");
    String strSavedNote5 = sharedPreferences.getString("NOTE5", "");
    String strSavedNote6 = sharedPreferences.getString("NOTE6", "");
    textSavedNote1.setText(strSavedNote1);
    textSavedNote2.setText(strSavedNote2);
    textSavedNote3.setText(strSavedNote3);
    textSavedNote4.setText(strSavedNote4);
    textSavedNote5.setText(strSavedNote5);
    textSavedNote6.setText(strSavedNote6);
   }

private void ClearTextViews(){ 

    SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.clear();
    editor.commit();

}

}

Answer 1

有一些链接可能会有所帮助

如何在 Android 中使用 SharedPreferences 来存储、获取和编辑值

http://developer.android.com/reference/android/content/SharedPreferences.html

例子

如何使用 SharedPreferences

http://android-er.blogspot.com.br/2011/01/example-of-using-sharedpreferencesedito.html

Answer 2

试试下面的代码。

/*I have added one more button, on click on that button i have set call clearText function and set all text     empty, each time before clicking on save button you click first clear button then next value will be inserted in next textview.*/
public class SharedPreferenceJustOneSetOfPreferencesActivity extends Activity implements OnClickListener{

    private Button saveNote,clearText,ClearAll;
    static TextView textSavedNote1, textSavedNote2, textSavedNote3, textSavedNote4, textSavedNote5, textSavedNote6;
    private EditText note;
    private SharedPreferences spNote;
    private static final String TAG = SharedPreferenceJustOneSetOfPreferencesActivity.class.getSimpleName();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        initView();
        saveInPreference();
    }

    private void initView() {
        textSavedNote1 = (TextView)findViewById(R.id.textSavedNote1);
        textSavedNote2 = (TextView)findViewById(R.id.textSavedNote2);
        textSavedNote3 = (TextView)findViewById(R.id.textSavedNote3);
        textSavedNote4 = (TextView)findViewById(R.id.textSavedNote4);
        textSavedNote5 = (TextView)findViewById(R.id.textSavedNote5);
        textSavedNote6 = (TextView)findViewById(R.id.textSavedNote6);
        note = (EditText)findViewById(R.id.note);
        saveNote = (Button)findViewById(R.id.saveNote);
        clearText = (Button)findViewById(R.id.clearText);
        ClearAll = (Button)findViewById(R.id.ClearAll);
        saveNote.setOnClickListener(this);
        clearText.setOnClickListener(this); 
        ClearAll.setOnClickListener(this);
    }
    private void saveInPreference() {
        spNote = PreferenceManager.getDefaultSharedPreferences(this);
        SharedPreferences.Editor edit = spNote.edit();
        edit.putString("note"+saveNote,note.getText().toString());
        edit.commit();
    }
    public boolean onCreateOptionsMenu(Menu menu){
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.layout.menu, menu);
        return true;        
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId()) {
        case R.id.item1:  Intent i = new Intent(SharedPreferenceJustOneSetOfPreferencesActivity.this, UserSettingActivity.class);
        startActivity(i);
        case R.id.item2:
                Intent intent = new Intent(SharedPreferenceJustOneSetOfPreferencesActivity.this, MainActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(intent);
                return true;
        case R.id.item3:
              finish();
              startActivity(getIntent());
            default:
                return super.onOptionsItemSelected(item);
        }
    }
    @Override
    public void onClick(View view) {
        if (view == saveNote) {
            String textvedNote1 =textSavedNote1.getText().toString();
            String textvedNote2= textSavedNote2.getText().toString();
            String textvedNote3 =textSavedNote3.getText().toString();
            String textvedNote4= textSavedNote4.getText().toString();
            String textvedNote5 =textSavedNote5.getText().toString();
            String textvedNote6= textSavedNote6.getText().toString();

            if (textvedNote1.equals("")) {          
                SavePreferences("NOTE1", note.getText().toString());
                Log.e(TAG,"textvedNote1: Inside "+textvedNote1.length());
                LoadPreferences();
                note.setText("");
            }else  if (textvedNote2.equals("")&& !textvedNote1.equals("")) {            
                SavePreferences("NOTE2", note.getText().toString());
                Log.e(TAG,"textvedNote2: Inside "+textvedNote1.length());
                LoadPreferences();
                note.setText("");
            } else if (textvedNote3.equals("")&& !textvedNote2.equals("")) {
                Log.e(TAG,"textvedNote3: Inside "+textvedNote2.length());
                SavePreferences("NOTE3", note.getText().toString());
                LoadPreferences();
                note.setText("");
            } else if (textvedNote4.equals("")&& !textvedNote3.equals("")) {
                Log.e(TAG,"textvedNote4: Inside "+textvedNote3.length());
                SavePreferences("NOTE4", note.getText().toString());
                LoadPreferences();
                note.setText("");
            } else if (textvedNote5.equals("")&& !textvedNote4.equals("")) {
                Log.e(TAG,"textvedNote5: Inside "+textvedNote4.length());
                SavePreferences("NOTE5", note.getText().toString());
                LoadPreferences();
                note.setText("");
            } else if (textvedNote6.equals("")&& !textvedNote5.equals("")) {
                SavePreferences("NOTE6", note.getText().toString());
                Log.e(TAG,"textvedNote6: Inside "+textvedNote5.length());
                LoadPreferences();
                note.setText("");
            }
        } else if (view == clearText) {
            ClearTextViews();
        }else if (view == ClearAll){
            ClearTextViews();
            textSavedNote1.setText("");
            textSavedNote2.setText("");
            textSavedNote3.setText("");         
            textSavedNote4.setText("");         
            textSavedNote5.setText("");
            textSavedNote6.setText("");
        }

    }
    private void SavePreferences(String key, String value){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
    }
    private void LoadPreferences(){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        String strSavedNote1 = sharedPreferences.getString("NOTE1", "");
        String strSavedNote2 = sharedPreferences.getString("NOTE2", "");
        String strSavedNote3 = sharedPreferences.getString("NOTE3", "");
        String strSavedNote4 = sharedPreferences.getString("NOTE4", "");
        String strSavedNote5 = sharedPreferences.getString("NOTE5", "");
        String strSavedNote6 = sharedPreferences.getString("NOTE6", "");
        if (!strSavedNote1.equals("")) {
            Log.e(TAG,"LoadPreferences1: "+strSavedNote1);
            textSavedNote1.setText(strSavedNote1);
        } else if (!strSavedNote2.equals("")) {
            Log.e(TAG,"LoadPreferences2:  "+strSavedNote2);
            textSavedNote2.setText(strSavedNote2);
        } else if (!strSavedNote3.equals("")) {
            Log.e(TAG,"LoadPreferences3:  "+strSavedNote3);
            textSavedNote3.setText(strSavedNote3);
        } else if (!strSavedNote4.equals("")) {
            textSavedNote4.setText(strSavedNote4);
        } else if (!strSavedNote5.equals("")) {
            textSavedNote5.setText(strSavedNote5);
        } else if (!strSavedNote6.equals("")) {
            textSavedNote6.setText(strSavedNote6);
        }
    }
    private void ClearTextViews(){
        SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear();
        editor.commit();
    }
}