没有启动活动的android putextra

概述我需要帮助.我有两个活动和一个数据库.我想要做的就是当我按下活动A中的按钮时,我将我的editText中的字符串发送到活动B.在活动B中,我尝试在我的数据库中插入该字符串并将其显示在列表视图中.如果我在活动A中启动活动B但是我不会显示活动B.这是我的代码：活动A：publicclassExam

我需要帮助.
我有两个活动和一个数据库.我想要做的就是当我按下活动A中的按钮时,我将我的editText中的字符串发送到活动B.在活动B中,我尝试在我的数据库中插入该字符串并将其显示在列表视图中.如果我在活动A中启动活动B但是我不会显示活动B.

这是我的代码：

活动A：

public class Example extends Activity {public final static String ID_EXTRA2="com.example.activitIEs";public EditText MyinputText = null;ImageVIEw Mybutton;TextVIEw MyOutputText, Myinputtext; /** Called when the activity is first created. */ @OverrIDe public voID onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentVIEw(R.layout.diccionary);MyinputText = (EditText)findVIEwByID(R.ID.inputText);MyOutputText = (TextVIEw)findVIEwByID(R.ID.OutputText);    Mybutton = (ImageVIEw)findVIEwByID(R.ID.botonaceptar);    Mybutton.setonClickListener(MybuttonOnClickListener); public ImageVIEw.OnClickListener MyTranslatebuttonOnClickListener = new ImageVIEw.OnClickListener(){ public voID onClick(VIEw v) {    String inputString;     inputString = MyinputText.getText().toString();    try{    Intent d = new Intent(Example.this, Secondactivity.class);           d.putExtra(ID_EXTRA2, inputString);           //startActivity(d); <----- If i start the secondactivity, that works...    }catch (Exception e){        }}};public boolean onCreateOptionsMenu(Menu menu){    super.onCreateOptionsMenu(menu);    MenuInflater awesome = getMenuInflater();    awesome.inflate(R.menu.main_menu, menu);    return true;}public boolean onoptionsItemSelected(MenuItem item){    switch(item.getItemID()){    case R.ID.menu1:        startActivity(new Intent("com.example.activitIEs.SECONDACTIVITY"));        return true;        case R.ID.menu2:        //something to do        return true;}    return false;}};

活动B：

public class Secondactivity extends Activity  {NoteAdapter2 adapter = null;NoteHelper2 helper2 = null;Cursor dataset_cursor2 = null;String entriID = null;public ListVIEw List2;String passeDWord = null;@OverrIDepublic voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentVIEw(R.layout.second);    try{    List2 = (ListVIEw)findVIEwByID(R.ID.List2);    helper2 = new NoteHelper2(this);    ---->passeDWord = getIntent().getStringExtra(Example.ID_EXTRA2);    ---->helper2.insert(passeDWord); //here i insert the string in my db        startManagingCursor(dataset_cursor2);        dataset_cursor2 = helper2.getAll();    adapter = new NoteAdapter2(dataset_cursor2);    List2.setAdapter(adapter);    dataset_cursor2.requery();    adapter.notifyDataSetChanged();    //this is how we kNow to do when a List item is clicked    List2.setonItemClickListener(onListClick);    }    catch (Exception e){    // this is the line of code that sends a real error message to the log    Log.e("ERROR", "ERROR IN CODE" + e.toString());    //this is the line that prints out the location in the code where the error ocurred    e.printstacktrace();    }}@OverrIDeprotected voID onDestroy() {    super.onDestroy();    helper2.close();}private AdapterVIEw.OnItemClickListener onListClick = new AdapterVIEw.OnItemClickListener() {    public voID onItemClick(AdapterVIEw<?> parent, VIEw vIEw, int position, long ID){        entriID = String.valueOf(ID);    }};class NoteAdapter2 extends CursorAdapter {    NoteAdapter2(Cursor c){        super(Zhistorytranslate.this, c);    }    public voID bindVIEw(VIEw row2, Context ctxt, Cursor c) {        NoteHolder2 holder2 = (NoteHolder2)row2.getTag();        holder2.populateFrom2(c, helper2);    }    public VIEw newVIEw(Context ctxt, Cursor c, VIEwGroup parent) {        LayoutInflater inflater = getLayoutInflater();        VIEw row2 = inflater.inflate(R.layout.row2, parent, false);        NoteHolder2 holder2 = new NoteHolder2(row2);        row2.setTag(holder2);        return (row2);    }    }static class NoteHolder2 {    private TextVIEw entriText = null;    NoteHolder2(VIEw row2){        entriText = (TextVIEw)row2.findVIEwByID(R.ID.entri);    }    voID populateFrom2(Cursor c, NoteHelper2 helper2) {        entriText.setText(helper2.getEntri(c));    }}

解决方法:

如果我理解正确,你想要在不启动B的情况下将数据从A发送到B.在这种情况下,你需要忘记Intents并考虑在你的应用程序中使用store data的方法.我的建议是使用SharedPreferences.

以下是如何使用它：

>在您的活动A中,存储字符串：

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);SharedPreferences.Editor editor = prefs.edit();editor.putString("string_ID", inputString); //inputString: from the EditTexteditor.commit();

>在活动B中,您可以通过以下方式获取值：

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);String data = prefs.getString("string_ID", "no ID"); //no ID: default value

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