Android Button setOnClickListener Design

Question

I am building an Android Application  I ve noticed that I am creating many repetitions of code similar to this in each of my classes   Button buttonX    Button findViewById R id buttonXName      Register the onClick listener with the implementation above buttonX setOnClickListener new OnClickListener         public void onClick View v                  DO SOMETHING   RUN SOME FUNCTION     DO CHECKS    ETC               I now have fifteen buttons and this is making my code ugly  Does anyone have a class or some examples on how I can turn all these codes into something more efficient  so I can    Create the button object  Button buttonX  Button findViewById R id buttonXName    Set the listener  buttonX setOnClickListener new OnClickListener    Determine if it was clicked  public void onClick View v   Then run specific code for each button    If anyone knows anything  I d appreciate it

User · Answer

You can use array to handle several button click listener in android like this: here i am setting button click listener for n buttons by using array as:

Button btn[] = new Button[n];

NOTE: n is a constant positive integer

Code example:

//class androidMultipleButtonActions 
package a.b.c.app;

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

public class androidMultipleButtonActions extends Activity implements OnClickListener{
    Button btn[] = new Button[3];

    public void onCreate(Bundle savedInstanceState) {   
    super.onCreate(savedInstanceState);
        setContentView(R.layout.main);        
        btn[0] = (Button) findViewById(R.id.Button1);
        btn[1] = (Button) findViewById(R.id.Button2);
        btn[2] = (Button) findViewById(R.id.Button3);
        for(int i=0; i<3; i++){
            btn[i].setOnClickListener(this);
        }           
    }

    public void onClick(View v) {
        if(v == findViewById(R.id.Button1)){
            //do here what u wanna do.
        }
        else if(v == findViewById(R.id.Button2)){
            //do here what u wanna do.
        }
        else if(v == findViewById(R.id.Button3)){
            //do here what u wanna do.
        }
    }
}

Note: First write an main.xml file if u dont know how to write please mail to: [email protected]

User · Answer

public class MainActivity extends AppCompatActivity  implements View OnClickListener       Button b1        Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity main           b1  Button findViewById R id button           b1 setOnClickListener this               Override     public void onClick View v            Toast makeText getApplicationContext    Button is Working  Toast LENGTH LONG  show

User · Answer

Android lambada solution  public void registerButtons        register R id buttonName1    - gt     Your code goes here          register R id buttonName2    - gt     Your code goes here          register R id buttonName3    - gt     Your code goes here         private void register int buttonResourceId  Runnable r       findViewById buttonResourceId  setOnClickListener v - gt  r run         Switch case solution solution  public void registerButtons        register R id buttonName1       register R id buttonName2       register R id buttonName3      private void register int buttonResourceId       findViewById buttonResourceId  setOnClickListener buttonClickListener      private OnClickListener buttonClickListener   new OnClickListener           Override     public void onClick View v           switch  v getId                  case R id buttonName1                     TODO Auto-generated method stub                 break              case R id buttonName2                     TODO Auto-generated method stub                 break              case View NO ID              default                     TODO Auto-generated method stub                 break

User · Answer

I think you can usually do what you need in a loop  which is much better than many onClick methods if it can be done   Check out this answer for a demonstration of how to use a loop for a similar problem  How you construct your loop will depend on the needs of your onClick functions and how similar they are to one another  The end result is much less repetitive code that is easier to maintain

User · Answer

public class MyActivity extends AppCompatActivity implements View OnClickListener         Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity scan options            Button button   findViewById R id button           Button button2   findViewById R id button2            button setOnClickListener this           button2 setOnClickListener this               Override     public void onClick View view             int id   view getId             switch  id                 case R id button                        Write your code here first button                  break                case R id button2                        Write your code here for second button                  break

User · Answer

Since setOnClickListener is defined on View not Button  if you don t need the variable for something else  you could make it a little terser like this   findViewById R id buttonXName  setOnClickListener new OnClickListener         public void onClick View v          DO SOMETHING   RUN SOME FUNCTION     DO CHECKS    ETC

User · Answer

Implement Activity with View OnClickListener like below   public class MyActivity extends AppCompatActivity implements View OnClickListener         Override     protected void onCreate Bundle savedInstanceState            super onCreate savedInstanceState           setContentView R layout activity scan options            Button button   findViewById R id button           Button button2   findViewById R id button2            button setOnClickListener this           button2 setOnClickListener this               Override     public void onClick View view             int id   view getId             switch  id                 case R id button                        Write your code here first button                  break                case R id button2                        Write your code here for second button                  break

User · Answer

If you re targeting 1 6 or later  you can use the android onClick xml attribute to remove some of the repetitive code  See this blog post by Romain Guy    lt Button     android height  wrap content     android width  wrap content     android onClick  myClickHandler    gt    And in the Java class  use these below lines of code   class MyActivity extends Activity       public void myClickHandler View target               Do stuff

User · Answer

Implement OnClickListener   on your Activity     public class MyActivity extends Activity implements View OnClickListener       For each button use     buttonX setOnClickListener this     In your Activity onClick   method test for which button it is      Override public void onClick View view        if  View equals buttonX              Do something     Also in onClick you could use view getId   to get the resource ID and then use that in a switch case block to identify each button and perform the relevant action

[android] Android Button setOnClickListener Design

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