单击按钮从Android中的EditText获取文本

Question

Hi I am working on calculator in android. I am having a EditText in wchich no will displayed depending on click of particular no.for example when user press 1 it will display 1.now when user clicks on 2 it will display 12 and so on.

i have things like this

  public class Main extends Activity implements OnClickListener {

   public static int no1=0,no2=0,op=0,flag=0;
   public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    EditText display1=(EditText) findViewById(R.id.display);    


     Button one= (Button) findViewById(R.id.one);  
     one.setOnClickListener(this);
   }


public void onClick(View v) {

    if(v.getId()==R.id.one)
    {
        switch(flag)
        {
        case 1:no1*=10+1;display1.setText(no1);
        case 2:no2*=10+1;display1.setText(no2);
        }


    }

but here i am getting error as "display1 cannot be resolved".

any solution to make work..??

Answer 1

Because it's only available in your onCreate method. Declare it as a field in your class.

private EditText display1;

Answer 2

Sometimes a complete code example helps:

public class Main extends Activity implements OnClickListener {

   private int no1=0;
   private int no2=0;
   private int op=0;
   private int flag=0;
   private EditText display1;

   public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);


     display1=(EditText) findViewById(R.id.display);    


     Button one= (Button) findViewById(R.id.one);  
     one.setOnClickListener(this);
   }


    public void onClick(View v) {

      if(v.getId()==R.id.one)
      {
        switch(flag)
        {
        case 1:no1*=10+1;display1.setText(no1);
        case 2:no2*=10+1;display1.setText(no2);
        }


   }
}

Basically you want to declare display1 as a private instance variable. The other variables do not need to be static, and should probably be declared private. And declarations formatted on separate lines for improved readability.

Have fun.

Answer 3

全局声明您的EditText和Button。

Answer 4

It should be better to keep a string showing in the EditText so that you have no difficulties appending and erasing. Then you can parse it to an integer so that you will be able to do math with it.

First you should declare your buttons and edit text globally:

public class Main extends Activity implements OnClickListener {
     private EditText display1 = (EditText) findViewById(R.id.display);    
     private Button one= (Button) findViewById(R.id.one);
     private Button two= (Button) findViewById(R.id.two);    

If you have the button label set as the number you can use it like this:

public void onClick(View view){
    display1.setText(display1.getText.toString() +  ((Button) view).getText().toString());
}    

That way, you can append the numbers to the end of the string in the display. If you want to use the number it's showing, you can use the following code:

int number = Integer.parseInt(display1.getText().toString());