Multiple Buttons' OnClickListener() android

问题:

I\'m currently making a simple calculator app on Android. Im trying to set up the code so that when a number button is pressed it updates the calculator screen with that number. Currently I\'m doing it like this.

    Button one = (Button) findViewById(R.id.oneButton);
    one.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            TextView output = (TextView) findViewById(R.id.output);
            output.append(\"1\");
        }
    });

It works but I\'m writing this same code for every single button on the calculator. As you can imagine it is very redundant. Is there anyway I can write this code in a more efficient way? One that involves not writing this method for every single button?

回答1:

You Just Simply have to Follow these steps for making it easy...

You don\'t have to write new onClickListener for Every Button... Just Implement View.OnClickLister to your Activity/Fragment.. it will implement new Method called onClick() for handling onClick Events for Button,TextView` etc.

1. Implement OnClickListener() in your Activity/Fragment

public class MainActivity extends Activity implements View.OnClickListener {

}

1. Implement onClick() method in your Activity/Fragment

public class MainActivity extends Activity implements View.OnClickListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public void onClick(View v) {
      // default method for handling onClick Events..
    }
}

1. Implement OnClickListener() For Buttons

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.your_layout);

    Button one = (Button) findViewById(R.id.oneButton);
    one.setOnClickListener(this); // calling onClick() method
    Button two = (Button) findViewById(R.id.twoButton);
    two.setOnClickListener(this);
    Button three = (Button) findViewById(R.id.threeButton);
    three.setOnClickListener(this);

}

1. Find Buttons By Id and Implement Your Code..

@Override
public void onClick(View v) {

    switch (v.getId()) {

        case R.id.oneButton:
            // do your code
            break;

        case R.id.twoButton:
            // do your code
            break;

        case R.id.threeButton:
            // do your code
            break;

        default:
            break;
    }

}

Please refer to this link for more information :

https://androidacademic.blogspot.in/2016/12/multiple-buttons-onclicklistener-android.html

This will make easier to handle many buttons click events and makes it looks simple to manage it...

回答2:

You could set the property:

android:onClick=\"buttonClicked\"

in the xml file for each of those buttons, and use this in the java code:

public void buttonClicked(View view) {

    if (view.getId() == R.id.button1) {
        // button1 action
    } else if (view.getId() == R.id.button2) {
        //button2 action
    } else if (view.getId() == R.id.button3) {
        //button3 action
    }

}

回答3:

I created dedicated class that implements View.OnClickListener.

public class ButtonClickListener implements View.OnClickListener {

    @Override
    public void onClick(View v) {
        Toast.makeText(MainActivity.this, \"Button Clicked\", Toast.LENGTH_SHORT).show();
    }

}

Then, I created an instance of this class in MainActivity

private ButtonClickListener onClickBtnListener = new ButtonClickListener();

and then set onClickListener for button

btn.setOnClickListener(onClickBtnListener);

回答4:

Set a Tag on each button to whatever you want to work with, in this case probably an Integer. Then you need only one OnClickListener for all of your buttons:

Button one = (Button) findViewById(R.id.oneButton);
Button two = (Button) findViewById(R.id.twoButton);
one.setTag(new Integer(1));
two.setTag(new Integer(2));

OnClickListener onClickListener = new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        TextView output = (TextView) findViewById(R.id.output);
        output.append(v.getTag());
    }
}

one.setOnClickListener(onClickListener);
two.setOnClickListener(onClickListener);

回答5:

public class MainActivity extends AppCompatActivity implements OnClickListener  {
    Button  b1,b2;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b1= (Button) findViewById(R.id.button);
        b2= (Button) findViewById(R.id.button2);
        b1.setOnClickListener(this);
        b2.setOnClickListener(this);
    }


    @Override
    public void onClick(View v)
    {
        if(v.getId()==R.id.button)
        {
            Intent intent=new Intent(getApplicationContext(),SignIn.class);
            startActivity(intent);
        }
        else if (v.getId()==R.id.button2)
        {
            Intent in=new Intent(getApplicationContext(),SignUpactivity.class);
            startActivity(in);
        }
    }
}

回答6:

    you can do like this

    TextView output = (TextView) findViewById(R.id.output);
    one.setOnClickListener(youractivity.this);
    // set the onclicklistener for other buttons also

    @Override
    public void onClick(View v) {
      int id = v.getId();
    switch(id) {
    case R.id.oneButton:      
       append(\"1\",output);
       break;
    case R.id.twoButton:
        append(\"2\",output);
       break;
    case R.id.threeButton:
        append(\"3\",output);
       break;
     } 
      }

 private void append(String s,TextView t){
  t.setText(s); 
}

    you can identify the views in your activity in a seperate method. 
    Hope this will help you.

回答7:

I had a similar issue and what I did is: Create a array of Buttons

Button buttons[] = new Button[10];

Then to implement on click listener and reference xml id\'s I used a loop like this

for (int i = 0; i < 10; i++) {      
String buttonID = \"button\" + i;
        int resID = getResources().getIdentifier(buttonID, \"id\",
                \"your package name here\");
        buttons[i] = (Button) findViewById(resID);
        buttons[i].setOnClickListener(this);
    }

But calling them up remains same as in Prag\'s answer point 4. PS- If anybody has a better method to call up all the button\'s onClick, please do comment.

回答8:

Implement onClick() method in your Activity/Fragment public class MainActivity extends Activity implements View.OnClickListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public void onClick(View v) {

switch (itemId) {

// if you call the fragment with nevigation bar then used.

       case R.id.nav_menu1:
            fragment = new IntroductionFragment();
            break;

// if call activity with nevigation bar then used.

        case R.id.nav_menu6:
            Intent i = new Intent(MainActivity.this, YoutubeActivity.class);
            startActivity(i);
  // default method for handling onClick Events..
}

}

回答9:

public void onClick(View v) {
    int id = v.getId();
    switch (id){
        case R.id.button1:
            //do ur code
            Toast.makeText(this,\"This is button 1\",Toast.LENGTH_SHORT).show();
            break;
        case R.id.button2:
            Intent intent = new Intent(this,SecondActivity.class);
            Intent.putExtra(\"key\",value);
            startActivity(intent);
            break;
        case R.id.button3:
            //do ur code
            break;
        case R.id.button4:
            //do ur code;
            break;
        default:
            //do ur code;
    }
}