java - 使用接口(interface)实现所有 Activity 的代码

Question

我正在尝试在每个 Activity 上实现一些代码，不想将代码复制并分页到每个 Activity 中。

最初，我只有一个父 Activity 和代码，然后扩展了所有其他 Activity ，但我无法在 ListActivities 或 ExpandableListActivities 上执行此操作。

我认为这将通过使用接口(interface)类然后让每个 Activity 实现它来完成。然而，当我尝试这样做时，Eclipse 给我一个错误并说要删除方法体。

这是我目前的情况

import android.content.Intent;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

public interface MenuOptions {

  /**
     * Method called when the hardware menu button is called. Uses optionmenu.xml for layout
     */
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.optionmenu, menu);
        return true;
    }

    /**
     * Event listener for the options menu. If home is pressed user is sent to home screen. If settings is pressed user is sent to setting screen
     * User is passed as an extra
     */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Intent nextIntent = null;

        switch (item.getItemId()) {
            case R.id.home:     
                        Toast.makeText(this, "You pressed the icon!", Toast.LENGTH_LONG).show();
                        nextIntent = new Intent(this, Home.class);

                      break;
            case R.id.settings:     
                        Toast.makeText(this, "You pressed the text!", Toast.LENGTH_LONG).show();
                        nextIntent = new Intent(this, Settings.class);
                      break;

        }

        nextIntent.putExtra("user", user);
        startActivity(nextIntent);
        return true;
    }

}

Answer 1

Java 中的

Interface 类应该只包含方法签名而不包含实现。因此你必须创建一个基类:

public class MenuOptions extends Activity {
  /**
     * Method called when the hardware menu button is called. Uses optionmenu.xml for layout
     */
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.optionmenu, menu);
        return true;
    }

    /**
     * Event listener for the options menu. If home is pressed user is sent to home screen. If settings is pressed user is sent to setting screen
     * User is passed as an extra
     */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Intent nextIntent = null;

        switch (item.getItemId()) {
            case R.id.home:     
                        Toast.makeText(this, "You pressed the icon!", Toast.LENGTH_LONG).show();
                        nextIntent = new Intent(this, Home.class);

                      break;
            case R.id.settings:     
                        Toast.makeText(this, "You pressed the text!", Toast.LENGTH_LONG).show();
                        nextIntent = new Intent(this, Settings.class);
                      break;

        }

        nextIntent.putExtra("user", user);
        startActivity(nextIntent);
        return true;
    }
}

以及您的 Activity :

public class YourActivity extends MenuOptions {
/*...*/
}