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如何在android studio中添加按鈕點擊事件

[英]how to add button click event in android studio

所以我做了一些研究,在通過代碼將你的按鈕定義為一個對象之后

private Button buttonname;
buttonname = (Button) findViewById(R.id.buttonnameinandroid) ;

這是我的問題

buttonname.setOnClickListener(this); //as I understand it, the "**this**" denotes the current `view(focus)` in the android program

然后你的OnClick()事件...

問題:

當我輸入“this”時,它說:

setOnClickListener (Android.View.view.OnClickListener) in View cannot be applied to (com.helloandroidstudio.MainActivity)

我不知道為什么?

這是 .java 文件中的代碼

import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

    private Button btnClick;
    private EditText Name, Date;
    private TextView msg, NameOut, DateOut;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btnClick = (Button) findViewById(R.id.button) ;
        btnClick.setOnClickListener(this);
        Name = (EditText) findViewById(R.id.textenter) ;
        Date = (EditText) findViewById(R.id.editText) ;
        msg = (TextView) findViewById(R.id.txtviewOut) ;
        NameOut = (TextView) findViewById(R.id.txtoutName) ;
        DateOut = (TextView) findViewById(R.id.txtOutDate) ;
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
    }

    public void onClick(View v)
    {
        if (v == btnClick)
        {
            if (Name.equals("") == false && Date.equals("") == false)
            {
                NameOut = Name;
                DateOut = Date;
                msg.setVisibility(View.VISIBLE);
            }
            else
            {
                msg.setText("Please complete both fields");
                msg.setVisibility(View.VISIBLE);
            }
        }
        return;

    }

View中的SetOnClickListener(Android.View.view.OnClickListener)不能應用於(com.helloandroidstudio.MainActivity)

這意味着換句話說(由於您當前的情況)您的 MainActivity 需要實現OnClickListener

public class Main extends ActionBarActivity implements View.OnClickListener {
   // do your stuff
}

這:

buttonname.setOnClickListener(this);

意味着您要為“在此實例上”的Button 分配偵聽器->此實例代表OnClickListener ,因此您的類必須實現該接口。

它類似於匿名偵聽器類(您也可以使用):

buttonname.setOnClickListener(new View.OnClickListener() {

   @Override
   public void onClick(View view) {

   }
});
Button button= (Button)findViewById(R.id.buttonId);
button.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
    // click handling code
   }
});
package com.mani.smsdetect;

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

public class MainActivity extends Activity implements View.OnClickListener {

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

        //Intialization Button

        btnClickMe = (Button) findViewById(R.id.btnClickMe);

        btnClickMe.setOnClickListener(MainActivity.this);
        //Here MainActivity.this is a Current Class Reference (context)
    }

    @Override
    public void onClick(View v) {

        //Your Logic
    }
}

當您以這種方式定義OnClickListener (或任何偵聽器)時

btnClick.setOnClickListener(this);

您需要在Activity implement OnClickListener

public class MainActivity extends ActionBarActivity implements OnClickListener{
public class MainActivity extends AppCompatActivity implements View.OnClickListener

每當您在點擊事件上使用 (this) 時,您的主要活動都必須實現 ocClickListener。 Android Studio 會為您完成,在“this”字樣上按 alt+enter。

package com.mani.helloworldapplication;

import android.app.Activity;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements View.OnClickListener {
    //Declaration
    TextView tvName;
    Button btnShow;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        //Empty Window
        super.onCreate(savedInstanceState);
        //Load XML File
        setContentView(R.layout.activity_main);

        //Intilization
        tvName = (TextView) findViewById(R.id.tvName);
        btnShow = (Button) findViewById(R.id.btnShow);

        btnShow.setOnClickListener(this);

    }

    @Override
    public void onClick(View v)
    {
        String name = tvName.getText().toString();
        Toast.makeText(MainActivity.this,name,Toast.LENGTH_SHORT).show();
    }
}

啟動您的 OnClickListener,但是當您到達第一個設置括號時,鍵入 new,然后鍵入 View,然后按 Enter。 完成后應該如下所示:

Button btn1 = (Button)findViewById(R.id.button1);

btn1.setOnClickListener(new View.OnClickListener() {            
    @Override
    public void onClick(View v) {
//your stuff here.
    }
});

//據我所知,“this”表示android程序中的當前視圖(焦點)

不,“this”僅在this引用的MainActivity實現View.OnClickListener ,這是setOnClickListener()方法的參數類型。 這意味着您應該在MainActivity實現View.OnClickListener

public class MainActivity extends Activity {

    Button button;

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

        button = (Button) findViewById(R.id.submitButton);
        button.setOnClickListener(new MyClass());

    }

    public class MyClass implements View.OnClickListener {

        @Override
        public void onClick(View v) {

        }

    }
}

我找到了一個視頻。 該視頻清楚地指導了如何處理按鈕單擊。 現在,我知道有三種方法可以處理Android中“視圖”上的事件點擊。

您可以簡單地在 Button 或任何使用 Lambda 表達式的東西上設置 onClickListener ,它看起來像

private Button buttonname;
buttonname = (Button)findViewById(R.id.buttonnameinandroid);

buttonname.setOnClickListener(v ->
    {
       //Your Listener Code Here
    });

在 Activity java 類中,您首先需要一個方法來查找按鈕的視圖:

btnSum =(Button)findViewById(R.id.button);

在此設置后單擊偵聽器

btnSum.setOnClickListener(new View.OnClickListener() {

並為您的功能覆蓋 onClick 方法。我在這里找到了一個完整的示例: http : //javainhouse.blogspot.in/2016/01/button-example-android-studio.html

您的Activity必須實現View.OnClickListener ,如下所示:

public class MainActivity extends 
Activity implements View.OnClickListener{
// YOUR CODE
}

MainActivity重寫方法onClick() ,如下所示:

@override
public void onClick (View view){
//here YOUR Action response to Click Button 
}

您什么都不用做,只需在btnClick.setOnClickListener()鍵入new View.OnClickListener() btnClick.setOnClickListener() 我的意思是你必須輸入btnClick.setOnClickListener(new View.onClickListener括號將保持打開狀態,只需按回車鍵,就會像這樣創建一個方法,

btnClick.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });

這只是意味着您正在創建 OnClickListener 的新視圖並將視圖作為參數傳遞。 現在你可以在 onClick(View v) 方法中做你應該做的任何事情。

處理按鈕事件的不同方式

Button btn1 = (Button)findViewById(R.id.button1);
btn1.setOnClickListener(new View.OnClickListener() {            
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Toast.makeText(context, "Button 1", 
     Toast.LENGTH_LONG).show();
        }
    });

[查看此文章以了解有關按鈕事件處理程序的更多詳細信息]

public class EditProfile extends AppCompatActivity {

    Button searchBtn;
    EditText userName_editText;
    EditText password_editText;
    EditText dob_editText;
    RadioGroup genderRadioGroup;
    RadioButton genderRadioBtn;
    Button editBtn;
    Button deleteBtn;
    Intent intent;
    DBHandler dbHandler;

    public static final String USERID_EDITPROFILE = "userID";

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

        searchBtn = (Button)findViewById(R.id.editprof_searchbtn);
        userName_editText = (EditText)findViewById(R.id.editprof_userName);
        password_editText = (EditText)findViewById(R.id.editprof_password);
        dob_editText = (EditText)findViewById(R.id.editprof_dob);
        genderRadioGroup = (RadioGroup)findViewById(R.id.editprof_radiogroup);
        editBtn = (Button)findViewById(R.id.editprof_editbtn);
        deleteBtn = (Button)findViewById(R.id.editprof_deletebtn);
        intent = getIntent();


        dbHandler = new DBHandler(EditProfile.this);

        setUserDetails();

        deleteBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String username = userName_editText.getText().toString();

                if(username == null){
                    Toast.makeText(EditProfile.this,"Please enter username to delete your profile",Toast.LENGTH_SHORT).show();
                }
                else{
                    UserProfile.Users users = dbHandler.readAllInfor(username);

                    if(users == null){
                        Toast.makeText(EditProfile.this,"No profile found from this username, please enter valid username",Toast.LENGTH_SHORT).show();
                    }
                    else{
                        dbHandler.deleteInfo(username);
                        Intent redirectintent_home = new Intent("com.modelpaper.mad.it17121002.Home");
                        startActivity(redirectintent_home);
                    }
                }
            }
        });

        editBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                String userID_String = intent.getStringExtra(Home.USERID);
                if(userID_String == null){
                    Toast.makeText(EditProfile.this,"Error!!",Toast.LENGTH_SHORT).show();
                    Intent redirectintent_home =  new Intent(getApplicationContext(),Home.class);
                    startActivity(redirectintent_home);
                }
                int userID = Integer.parseInt(userID_String);

                String username = userName_editText.getText().toString();
                String password = password_editText.getText().toString();
                String dob = dob_editText.getText().toString();
                int selectedGender = genderRadioGroup.getCheckedRadioButtonId();
                genderRadioBtn = (RadioButton)findViewById(selectedGender);
                String gender = genderRadioBtn.getText().toString();

                UserProfile.Users users = UserProfile.getProfile().getUser();
                users.setUsername(username);
                users.setPassword(password);
                users.setDob(dob);
                users.setGender(gender);
                users.setId(userID);

                dbHandler.updateInfor(users);
                Toast.makeText(EditProfile.this,"Updated Successfully",Toast.LENGTH_SHORT).show();
                Intent redirectintent_home = new Intent(getApplicationContext(),Home.class);
                startActivity(redirectintent_home);
            }
        });

        searchBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
               String username = userName_editText.getText().toString();
               if (username == null){
                   Toast.makeText(EditProfile.this,"Please enter a username",Toast.LENGTH_SHORT).show();
               }
               else{
                   UserProfile.Users users_search = dbHandler.readAllInfor(username);


                   if(users_search == null){
                       Toast.makeText(EditProfile.this,"Please enter a valid username",Toast.LENGTH_SHORT).show();
                   }
                   else{
                       userName_editText.setText(users_search.getUsername());
                       password_editText.setText(users_search.getPassword());
                       dob_editText.setText(users_search.getDob());
                       int id = users_search.getId();
                       Intent redirectintent = new Intent("com.modelpaper.mad.it17121002.EditProfile");
                       redirectintent.putExtra(USERID_EDITPROFILE,Integer.toString(id));
                       startActivity(redirectintent);
                   }
               }
            }
        });


    }

    public void setUserDetails(){

        String userID_String = intent.getStringExtra(Home.USERID);
        if(userID_String == null){
            Toast.makeText(EditProfile.this,"Error!!",Toast.LENGTH_SHORT).show();
            Intent redirectintent_home = new Intent("com.modelpaper.mad.it17121002.Home");
            startActivity(redirectintent_home);
        }
        int userID = Integer.parseInt(userID_String);
        UserProfile.Users users = dbHandler.readAllInfor(userID);
        userName_editText.setText(users.getUsername());
        password_editText.setText(users.getPassword());
        dob_editText.setText(users.getDob());
    }
}

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