Android中的菜单 _Android

仓廪实则知礼节，衣食足则知荣辱。这篇文章主要讲述Android中的菜单相关的知识，希望能为你提供帮助。
***android中的菜单
*OptionsMenu:
onCreatOptiodMenu()方法
首先在menu文件夹下创建options_menu.xml文件：

< item android:id="@+id/action_search" android:title="@string/action_search"/> < item android:id="@+id/action_settings" android:title="@string/action_settings"/>

MainActivity.java中:

public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } //创建选项菜单--OptionsMenu @Override public boolean onCreateOptionsMenu(Menu menu) { //获取菜单填充器对象 MenuInflater menuinflater = getMenuInflater(); //将menu的xml文件转换成menu对象 menuinflater.inflate(R.menu.options_menu, menu); //也可以通过代码形式添加菜单项 menu.add(Menu.NONE, Menu.NONE,Menu.NONE, "扫描"); //返回必须是true，否则不显示menu return true; } //处理OptionMenu的点击事件 @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.action_search: Toast.makeText(MainActivity.this, "搜索", Toast.LENGTH_SHORT).show(); break; case R.id.action_settings: Toast.makeText(MainActivity.this, "设置", Toast.LENGTH_SHORT).show(); default: break; } return super.onOptionsItemSelected(item); } }

*ContextMenu:
onCreatContextMenu()方法

案例效果：需长按textview控件才可显示出菜单，通过选择相应的菜单项，在title中显示控件宽高

在activity_main.xml布局文件中添加一个textView控件，values文件夹下的main.xml文件中：

< item android:id="@+id/action_height" android:title="@string/action_height"/> < item android:id="@+id/action_width" android:title="@string/action_width"/>

MainActivity.java中：

public class MainActivity extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv = (TextView) findViewById(R.id.tv); registerForContextMenu(tv); //必须注册上下文菜单--> 通常上下文菜单是和ListView或者GridView这种适配器控件绑定在一起 } @Override public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { MenuInflater menuinflater = getMenuInflater(); menuinflater.inflate(R.menu.main, menu); super.onCreateContextMenu(menu, v, menuInfo); } @Override public boolean onContextItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.action_height: setTitle("控件的高度="+tv.getHeight()); break; case R.id.action_width: setTitle("控件的宽度="+tv.getWidth()); default: break; } return super.onContextItemSelected(item); } }

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*PopupMenu:
PopupMenu popMenu = new PopupMenu(this,v)

案例显示效果：通过点击button按钮显示出菜单选项，通过选择相应的菜单选项设置textview中字体的增大和减小

activity_main.xml中布局：

< Button android:layout_width="match_parent" android:layout_height="wrap_content" android:onClick="showPopup" android:textColor="#fff" android:background="#90C552" android:text="显示PopupMenu"/> < TextView android:id="@+id/tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="@string/hello_world" />

menu文件夹下的main.xml中设置菜单选项：

< item android:id="@+id/action_textadd" android:title="@string/action_textadd"/> < item android:id="@+id/action_textsub" android:title="@string/action_textsub"/>

MainActivity.java文件中：

public class MainActivity extends Activity { private float fontSize =15.0f; private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv = (TextView) findViewById(R.id.tv); } public void showPopup(View view){ PopupMenu popupmenu = new PopupMenu(this, view); //第二个参数anchor:锚点，popupmenu想要显示出来必须与一个控件绑定在一起，所以这里将其与view绑定，view也就是button getMenuInflater().inflate(R.menu.main, popupmenu.getMenu()); popupmenu.show(); //处理菜单选项点击事件 popupmenu.setOnMenuItemClickListener(new OnMenuItemClickListener() {@Override public boolean onMenuItemClick(MenuItem item) { switch (item.getItemId()) { case R.id.action_textadd: fontSize+=5; break; case R.id.action_textsub: fontSize-=5; default: break; } tv.setTextSize(fontSize); return false; } }); } }

【Android中的菜单】