如何在活動中顯示對話框中的edittext輸入

剛纔忘了指出，在對話框中編輯文本：

number1 = (EditText)dialogcalc.findViewById(R.id.number1); 
number2 = (EditText)dialogcalc.findViewById(R.id.number2);

我試圖做出乘以來自用戶的數量的計算器。該數字可以放在對話框中的Edittext中。點擊對話框上的按鈕計算結果後，該數字必須乘以數字，並顯示在激活對話框的活動中。當我點擊計算按鈕時出現錯誤，我做錯了什麼？

的main.xml（對話）

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
android:orientation="vertical" > 

<!-- number 1 --> 
<LinearLayout 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:orientation="horizontal" > 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="number:" /> 
    <EditText 
     android:id="@+id/number1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:hint="0" 
     android:inputType="number" 
     android:layout_marginLeft="20dp" /> 
</LinearLayout> 

<!-- number 2 --> 
<LinearLayout 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
android:orientation="horizontal" > 
    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="number:" /> 
    <EditText 
     android:id="@+id/number2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:hint="0" 
     android:inputType="number" 
     android:layout_marginLeft="20dp" /> 
</LinearLayout> 


<Button 
    android:id="@+id/btncalculate" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Calculate"/> 

<Button 
    android:id="@+id/btnreset" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Reset" /> 

</LinearLayout>

Java文件：

package com.tip.calc; 

import android.app.Activity; 
import android.app.Dialog; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.ImageView; 
import android.widget.TextView; 


public class OverviewpageActivity extends Activity { 
private TextView multiplydisplay; 
private TextView multiply2display; 
private Button btntocalculator; 
private Button btnpopup; 

private EditText number1; 
private EditText number2; 

private double number1calc = 0; 
private double number2calc = 0; 
private double multiply  = 0; 
private double multiply2  = 0; 

/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.overview); 

    multiplydisplay = (TextView)findViewById(R.id.multiplydisplay); 
    multiply2display = (TextView)findViewById(R.id.multiplydisplay2); 
    btntocalculator = (Button)findViewById(R.id.btntocalculator); 
    btnpopup = (Button)findViewById(R.id.btnpopup); 


    btntocalculator.setOnClickListener(new Button.OnClickListener() { 
     public void onClick (View v) { 

      final Dialog dialogcalc = new Dialog(OverviewpageActivity.this); 
      dialogcalc.setContentView(R.layout.main); 
      dialogcalc.setTitle("calc"); 
      dialogcalc.setCancelable(true); 

      Button buttoncalculate = (Button) dialogcalc.findViewById(R.id.btncalculate); 
      buttoncalculate.setOnClickListener(new OnClickListener() { 
       public void onClick(View v) { 

         if(number1.getText().toString().trim().length() < 1){number1calc=0;} 
         else{number1calc=Double.parseDouble(number1.getText().toString());} 

         if(number2.getText().toString().trim().length() < 1){number2calc=0;} 
         else{number2calc=Double.parseDouble(number2.getText().toString());} 

         //calculate 
         multiply=(number1calc*number2calc)*0.222; 
         multiply2=(number1calc*number2calc)*0.888; 

         //display 
         multiplydisplay.setText(Double.toString(multiply)); 
         multiply2display.setText(Double.toString(multiply2)); 

        dialogcalc.dismiss(); 
       } 
      }); 

      dialogcalc.show(); 

     } 
    }); 

    btnpopup.setOnClickListener(new OnClickListener() { 
     public void onClick(View v) { 
      //set up dialog 
      final Dialog dialog = new Dialog(OverviewpageActivity.this); 
      dialog.setContentView(R.layout.custom_dialog); 
      dialog.setTitle("This is my custom dialog box"); 
      dialog.setCancelable(true); 

      TextView text = (TextView) dialog.findViewById(R.id.TextView01); 
      text.setText(R.string.about); 

      ImageView img = (ImageView) dialog.findViewById(R.id.ImageView01); 
      img.setImageResource(R.drawable.carbon); 

      Button button = (Button) dialog.findViewById(R.id.Button01); 
      button.setOnClickListener(new OnClickListener() { 
       public void onClick(View v) { 
        dialog.dismiss(); 
       } 
      }); 
      dialog.show(); 
     } 
    }); 

} 
}

來源

2012-01-30 John

什麼是錯誤？ – 2012-01-30 11:09:39

就這麼簡單

AlertDialog.Builder alert = new AlertDialog.Builder(this); 

alert.setTitle("Title"); 
alert.setMessage("Message"); 

// Set an EditText view to get user input 
final EditText input = new EditText(this); 
alert.setView(input); 

alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() { 
public void onClick(DialogInterface dialog, int whichButton) { 
    String value = input.getText().toString(); 
    // Do something with value! 
    } 
}); 

alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
    public void onClick(DialogInterface dialog, int whichButton) { 
    // Canceled. 
    } 
}); 

alert.show();

來源

2012-01-30 11:09:54

工作正常，應該是被接受的答案。 – astuter 2014-03-13 11:41:09

我覺得這是你的問題：

number1.getText().toString().trim().length()

你永遠不會實例化number1。它是空的。我很確定這是爲你造成一個NullPointer。

來源

2012-01-30 11:11:46

修復了NumberFormatExceptions和一些NPE的OverviewpageActivity。它現在有效。我沒有使用你的佈局。只是手工做的。

import android.app.Activity; 
import android.app.Dialog; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.*; 


public class OverviewpageActivity extends Activity { 
private TextView multiplydisplay; 
private TextView multiply2display; 
private Button btntocalculator; 


private EditText number1; 
private EditText number2; 

private double number1calc = 0; 
private double number2calc = 0; 
private double multiply  = 0; 
private double multiply2  = 0; 

/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    LinearLayout rl = new LinearLayout (this); 

    rl.setOrientation(1); 

    multiplydisplay = new TextView(this); 
    multiply2display = new TextView(this); 
    btntocalculator = new Button(this); 

    btntocalculator.setText("calc"); 
    rl.addView(multiplydisplay); 
    rl.addView(multiply2display); 
    rl.addView(btntocalculator); 


    btntocalculator.setOnClickListener(new Button.OnClickListener() { 
     public void onClick (View v) { 

      final Dialog dialogcalc = new Dialog(OverActivity.this); 
      //dialogcalc.setContentView(R.layout.main); 
      LinearLayout rl = new LinearLayout (OverActivity.this); 

    rl.setOrientation(1); 
      number1 = new EditText(OverActivity.this); 
      number2 = new EditText(OverActivity.this); 
      number1.setWidth(50); 
      number2.setWidth(50); 
      rl.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT)); 
      rl.addView(number1); 
      rl.addView(number2); 


      dialogcalc.setTitle("calc"); 
      dialogcalc.setCancelable(true); 

      Button buttoncalculate = new Button(OverActivity.this); 
      buttoncalculate.setText("do calc"); 
      rl.addView(buttoncalculate); 
      dialogcalc.setContentView(rl); 
      buttoncalculate.setOnClickListener(new OnClickListener() { 
       public void onClick(View v) { 
          try{ 
         if(number1.getText().toString().trim().length() < 1){number1calc=0;} 
         else{number1calc=Double.parseDouble(number1.getText().toString());} 

         if(number2.getText().toString().trim().length() < 1){number2calc=0;} 
         else{number2calc=Double.parseDouble(number2.getText().toString());} 
          }catch (NumberFormatException nfe) 
          { 
           nfe.printStackTrace(); 
          } 


         //calculate 
         multiply=(number1calc*number2calc)*0.222; 
         multiply2=(number1calc*number2calc)*0.888; 

         //display 
         multiplydisplay.setText(Double.toString(multiply)); 
         multiply2display.setText(Double.toString(multiply2)); 

        dialogcalc.dismiss(); 
       } 
      }); 

      dialogcalc.show(); 

     } 
    }); 


    setContentView(rl); 
} 
}

來源

2012-01-30 11:35:37

如何在活動中顯示對話框中的edittext輸入

回答

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