將Edittext的值存儲在字符串中？

Question

我想獲得edittext的值並將其放入烤麪包。 顯然這行代碼有問題，因爲應用程序崩潰時，我打好了。

String newItem = et_getItem.getText().toString(); 

編輯：這是全班同學：

public class MainActivity extends AppCompatActivity { 

TextView txt_array; 


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


    Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar); 
    setSupportActionBar(myToolbar); 

    txt_array = (TextView) findViewById(R.id.txt_array); 

} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.toolbar_menu, menu); 
    return true; 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 

    int id = item.getItemId(); 

    if (id == R.id.action_add) { 

     openDialog(); 

     return true; 
    } 

    return super.onOptionsItemSelected(item); 
} 

private void openDialog() { 

    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); 

    LayoutInflater inflater = MainActivity.this.getLayoutInflater(); 

    // Inflate and set the layout for the dialog 
    // Pass null as the parent view because its going in the dialog layout 
    View theInflatedView = inflater.inflate(R.layout.dialog_add, null); 
    builder.setView(theInflatedView); 


    builder.setPositiveButton("Okay!", new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int id) { 
      EditText et_getItem = (EditText) findViewById(R.id.et_add); 
      String newItem = et_getItem.getText().toString(); 

      Toast.makeText(getApplicationContext(), "The item " + newItem + " has been added!", Toast.LENGTH_SHORT).show(); 
     } 
    }); 
    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int id) { 
      dialog.cancel(); 
     } 
    }); 



    //AFTER setting the properties, create the dialog! 
    AlertDialog dialog = builder.create(); 

    //AFTER creating the dialog, don't forget to show it! 
    dialog.show(); 
} 

}

這是dialog_add.xml文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:orientation="vertical"> 

<EditText 
    android:id="@+id/et_add" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_marginBottom="4dp" 
    android:layout_marginLeft="4dp" 
    android:layout_marginRight="4dp" 
    android:layout_marginTop="16dp" 
    android:digits="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" 
    android:hint="Type in a list item..." 
    android:inputType="textCapWords" /> 
</LinearLayout> 

的logcat：

02-28 18:36:29.156 5913-5913/com.smaragd16.mylist E/AndroidRuntime: FATAL EXCEPTION: main 
                   Process: com.smaragd16.mylist, PID: 5913 
                   java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference 
                    at com.smaragd16.mylist.MainActivity$1.onClick(MainActivity.java:71) 
                    at android.support.v7.app.AlertController$ButtonHandler.handleMessage(AlertController.java:157) 
                    at android.os.Handler.dispatchMessage(Handler.java:102) 
                    at android.os.Looper.loop(Looper.java:148) 
                    at android.app.ActivityThread.main(ActivityThread.java:5525) 
                    at java.lang.reflect.Method.invoke(Native Method) 
                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:730) 
                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:620) 

Answer 1

試試這個：

View theInflatedView = inflater.inflate(R.layout.dialog_add, null); 
builder.setView(theInflatedView); 

代替

builder.setView(inflater.inflate(R.layout.dialog_add, null)); 

而且你想既然已經對話框的佈局中聲明來初始化錯誤引用的EditText，你應該做它作爲

EditText et_getItem = (EditText) dialog.findViewById(R.id.et_add); 

而不是

EditText et_getItem = (EditText) findViewById(R.id.et_add); 

我希望它適合你。