Android开发：结合两个Java文件

Question

我有两个不同的java文件，并且想知道是否有办法将它们组合起来，以便两个代码都在一个文件中。

下面简单地创建一个对话框，在没有单击时不执行任何操作，如果单击是，则移动到新活动：

package com.example.top_tech_deals;


import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;



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


    Button btnAlertTwoBtns = (Button) findViewById(R.id.btnAlertWithTwoBtns);






    /**
     * Showing Alert Dialog with Two Buttons one Positive Button with Label
     * "YES" one Negative Button with Label "NO"
     */
    btnAlertTwoBtns.setOnClickListener(new View.OnClickListener() {

        public void onClick(View arg0) {
            // Creating alert Dialog with two Buttons

            AlertDialog.Builder alertDialog = new AlertDialog.Builder(AlertDialogActivity.this);

            // Setting Dialog Title
            alertDialog.setTitle("Confirm Delete...");

            // Setting Dialog Message
            alertDialog.setMessage("Are you sure you want delete this?");

            // Setting Icon to Dialog
            alertDialog.setIcon(R.drawable.delete);

            // Setting Positive "Yes" Button
            alertDialog.setPositiveButton("YES",
                    new DialogInterface.OnClickListener() {
                        public void onClick (DialogInterface dialog,int which) {
                            // Write your code  here to execute after dialog

                            Intent k = new  Intent(AlertDialogActivity.this, Camera.class);
                             startActivity(k);

                            Toast.makeText (getApplicationContext(), "You clicked on YES", Toast.LENGTH_SHORT).show();
                        }
                    });
            // Setting Negative "NO" Button
            alertDialog.setNegativeButton("NO",
                    new DialogInterface.OnClickListener() {
                        public void onClick (DialogInterface dialog,    int which) {
                            // Write your code  here to execute after dialog
                            Toast.makeText (getApplicationContext(), "You clicked on NO", Toast.LENGTH_SHORT).show();
                            dialog.cancel();
                        }
                    });

            // Showing Alert Message
            alertDialog.show();

        }
    });

}
}

第二个代码创建一个下拉菜单，其中包含用户可以选择的项目：

package com.example.top_tech_deals;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
import android.widget.AdapterView.OnItemSelectedListener;

public class AndroidSpinnerExampleActivity extends Activity implements OnItemSelectedListener{
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.spinex);

    // Spinner element
    Spinner spinner = (Spinner) findViewById(R.id.spinner);

    // Spinner click listener
    spinner.setOnItemSelectedListener(this);

    // Spinner Drop down elements
    List<String> categories = new ArrayList<String>();
    categories.add("Automobile");
    categories.add("Business Services");
    categories.add("Computers");
    categories.add("Education");
    categories.add("Personal");
    categories.add("Travel");

    // Creating adapter for spinner
    ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,  android.R.layout.simple_spinner_item, categories);

    // Drop down layout style - list view with radio button
    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    // attaching data adapter to spinner
    spinner.setAdapter(dataAdapter);
}

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    // On selecting a spinner item
    String item = parent.getItemAtPosition(position).toString();

    // Showing selected spinner item
    Toast.makeText(parent.getContext(), "Selected: " + item, Toast.LENGTH_LONG).show ();

}

public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub

}

}

基本上我想要的是我的一个xml文件，它同时使用了一个对话框和一个下拉菜单，但是因为我在将这两个代码放入一个java文件时遇到了麻烦，我使用了创建两个不同的xml文件。链接到AlertDialogActivity的xml和链接到AndroidSpinnerExampleActivity的spinex.xml。我尝试将两个java文件链接到同一个xml但我发现只有一个java文件似乎做了什么，所以我相信唯一的解决办法就是将这两个代码组合成一个java文件，但我似乎总是会出错我试试的时候。

Answer 1

每个公共类必须位于单独的文件中，文件名与类相同。但是，如果您将其中一个课程更改为不公开，那么确定。我认为最佳做法是保持文件不变。将您的课程放在单独的文件中，以便将来可维护性更好，这样您就可以轻松找到您的课程。

Answer 2

  

基本上我想要的是我的一个xml文件同时使用一个对话框   框和下拉菜单，但是因为我在放置时遇到了麻烦   将这两个代码放入一个java文件中，我使用了两个   不同的xml文件，post.xml链接到AlertDialogActivity   和spinex.xml链接到AndroidSpinnerExampleActivity。

请按照以下步骤操作：

• 创建一个包含Button和Spinner。
的布局文件
• 创建一个扩展Activity并实现OnItemSelectedListener接口
的类
• 将先前创建的布局设置为上述活动的内容视图
您将拥有onCreate方法中的

• ：

  setContentView(R.layout.combinedlayout); 
  // must be in the combinedlayout
  Button btnAlertTwoBtns = (Button) findViewById(R.id.btnAlertWithTwoBtns);
  btnAlertTwoBtns.setOnClickListener(new View.OnClickListener() {
     // the rest of the listener code from your first class.
  }
  // must be in the combinedlayout
  Spinner spinner = (Spinner) findViewById(R.id.spinner);
  
  // Spinner click listener
  spinner.setOnItemSelectedListener(this);
  
  // Spinner Drop down elements
  List<String> categories = new ArrayList<String>();
  categories.add("Automobile");
  categories.add("Business Services");
  categories.add("Computers");
  categories.add("Education");
  categories.add("Personal");
  categories.add("Travel");
  
  // Creating adapter for spinner
  ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,  android.R.layout.simple_spinner_item, categories);
  
  // Drop down layout style - list view with radio button
  dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  
  // attaching data adapter to spinner
  spinner.setAdapter(dataAdapter);
  

Answer 3

我对你的问题有点困惑。你想组合这些活动，以便你有一个活动，同时打开对话框的按钮和屏幕上的微调器？如果是这样，你应该能够做到这一点。

只需创建一个包含按钮和微调器的xml文件：

<Button
    .... />

<Spinner
    .... />

然后，你可以只有一个Activity来引用微调器和按钮，填充微调器并将一个onItemSelectedListener赋给微调器。您可以像以前一样处理按钮。

import android.widget.AdapterView.OnItemSelectedListener;

public class AndroidSpinnerAndButtonExampleActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.your_layout);

        // Spinner element
        Spinner spinner = (Spinner) findViewById(R.id.spinner);


        // Spinner Drop down elements
        List<String> categories = new ArrayList<String>();
        categories.add("Automobile");
        categories.add("Business Services");
        categories.add("Computers");
        categories.add("Education");
        categories.add("Personal");
        categories.add("Travel");

        // Creating adapter for spinner
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,  android.R.layout.simple_spinner_item, categories);

        // Drop down layout style - list view with radio button
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        // attaching data adapter to spinner
        spinner.setAdapter(dataAdapter);

        setSpinnerOnItemSelectedListener(spinner);

        Button btnAlertTwoBtns = (Button) findViewById(R.id.btnAlertWithTwoBtns);

        /**
         * Showing Alert Dialog with Two Buttons one Positive Button with Label
         * "YES" one Negative Button with Label "NO"
         */
        btnAlertTwoBtns.setOnClickListener(new View.OnClickListener() {

                public void onClick(View arg0) {
                // Creating alert Dialog with two Buttons

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

                // Setting Dialog Title
                alertDialog.setTitle("Confirm Delete...");

                // Setting Dialog Message
                alertDialog.setMessage("Are you sure you want delete this?");

                // Setting Icon to Dialog
                alertDialog.setIcon(R.drawable.delete);

                // Setting Positive "Yes" Button
                alertDialog.setPositiveButton("YES",
                    new DialogInterface.OnClickListener() {
                    public void onClick (DialogInterface dialog,int which) {
                    // Write your code  here to execute after dialog

                    Intent k = new  Intent(this, Camera.class);
                    startActivity(k);

                    Toast.makeText (getApplicationContext(), "You clicked on YES", Toast.LENGTH_SHORT).show();
                    }
                    });
                // Setting Negative "NO" Button
                alertDialog.setNegativeButton("NO",
                        new DialogInterface.OnClickListener() {
                        public void onClick (DialogInterface dialog,    int which) {
                        // Write your code  here to execute after dialog
                        Toast.makeText (getApplicationContext(), "You clicked on NO", Toast.LENGTH_SHORT).show();
                        dialog.cancel();
                        }
                        });

                // Showing Alert Message
                alertDialog.show();

                }
        });
    }

    public void setSpinnerOnItemSelectedListener(Spinner spinner){
        spinner.setOnItemSelectedListener(new OnItemSelectedListener(){
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                // On selecting a spinner item
                String item = parent.getItemAtPosition(position).toString();

                // Showing selected spinner item
                Toast.makeText(parent.getContext(), "Selected: " + item, Toast.LENGTH_LONG).show ();

            }

            public void onNothingSelected(AdapterView<?> arg0) {
                // TODO Auto-generated method stub

            }
    });
}

}