java - 创建可重用类

Question

我有一个在 Android 中运行的应用程序，我想创建一个菜单并在某些 Activity 中重复，该菜单调用 Intent 以打开其他 Activity 。

我该怎么做？

我想也许我可以创建一个类，但我遇到了错误。我在哪里可以为此创建一个类？是否在 onCreate 方法内部？我怎样才能在另一个 Activity 中重复使用菜单？

谢谢!!

这是我的菜单代码:

menu_button = (Button) findViewById(R.id.menu_button);
    menu_button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            PopupMenu popupMenu = new PopupMenu(MainActivity.this, menu_button);
            popupMenu.getMenuInflater().inflate(R.menu.popup_menu, popupMenu.getMenu());

            popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                @Override
                public boolean onMenuItemClick(MenuItem item) {
                    switch (item.getItemId()) {
                        case R.id.one:
                            Intent vista = new Intent(MainActivity.this, openCamera.class);
                            MainActivity.this.startActivity(vista);

                    }
                    return true;

                    /*
                    Toast.makeText(MainActivity.this, "" + item.getTitle(), Toast.LENGTH_SHORT).show();
                    return true;
                    */
                }
            });
            popupMenu.show();
        }
    });

Answer 1

如果菜单总是一样的，并且你想在多个 Activity 中重复使用它，你只需像这样定义它:

public class TestMenu {

    private final PopupMenu popupMenu;

    public TestMenu(final Activity activity, View anchor) {
        popupMenu = new PopupMenu(activity, anchor);
        popupMenu.getMenuInflater().inflate(R.menu.popup_menu, popupMenu.getMenu());

        popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                switch (item.getItemId()) {
                    case R.id.one:
                        Intent vista = new Intent(activity, openCamera.class);
                        activity.startActivity(vista);
                }
                return true;
            }
        });
    }

    public void show() {
        popupMenu.show();
    }
}

然后像这样在您的 Activity 中使用它:

public class TestActivity extends Activity {

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

        Button menu_button = (Button) findViewById(R.id.menu_button);
        TestMenu myMenu = new TestMenu(this, menu_button);
        menu_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myMenu.show();
            }
        });
    }
}