02安卓用户界面优化之（三）如何使用菜单

一、选项菜单（OptionsMenu）

在程序中直接通过代码创建选项菜单时需重写Activity的onCreateOptionsMenu和onOptionsItemSelected方法，其中onCreateOptionsMenu中用于创建菜单，onOptionsItemSelected用于监测菜单中哪一项被选中并在程序中做出响应。

public boolean onCreateOptionsMenu(Menu menu);通过调用Menu的addSubMenu方法返回一个SubMenu的子菜单，再调用SubMenu的add方法添加子菜单项。

public boolean onOptionsItemSelected(MenuItem item) ;通过调用MenuItem的getItemId方法来获得是哪个菜单项被选中，从而做出响应。

 

public boolean onOptionsItemSelected(MenuItem item)；

package com.example.shiyanshi.usingmenu;

import android.content.Intent;
import android.content.res.Resources;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView textView;

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

        textView=(TextView)findViewById(R.id.textView);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        SubMenu fontSize=menu.addSubMenu("字体大小");
        fontSize.add(0,R.dimen.FONT_10,0,"10号字体");
        fontSize.add(0,R.dimen.FONT_12,0,"12号字体");
        fontSize.add(0,R.dimen.FONT_14,0,"14号字体");
        fontSize.add(0,R.dimen.FONT_16,0,"16号字体");
        fontSize.add(0,R.dimen.FONT_18,0,"18号字体");
        fontSize.add(0,R.dimen.FONT_20,0,"20号字体");

        SubMenu ordinaryMenu=menu.addSubMenu("普通菜单项");

        SubMenu fontColor=menu.addSubMenu("字体颜色");
        fontColor.setHeaderTitle("选择字体颜色");
        fontColor.add(0, R.color.FONT_RED, 0, "红色");
        fontColor.add(0, R.color.FONT_GREEN, 0, "绿色");
        fontColor.add(0, R.color.FONT_BLUE, 0, "蓝色");

        SubMenu prog=menu.addSubMenu("启动程序");
        prog.setHeaderTitle("选择你要启动的程序");
        MenuItem item=prog.add("查看Swift");
        item.setIntent(new Intent(MainActivity.this,AnotherActivity.class));


//        MenuItem item1=prog.add("打开另外一个Activity");
//        item1.setIntent(new Intent(MainActivity.this,ThirdActivity.class));
        prog.add("打开另外一个Activity").setIntent(new Intent(MainActivity.this,ThirdActivity.class));

        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        Resources resources=MainActivity.this.getResources();

        switch (item.getItemId()){
            case R.dimen.FONT_10:
                textView.setTextSize(resources.getDimension(R.dimen.FONT_10));
                break;
             case R.dimen.FONT_12:
                textView.setTextSize(resources.getDimension(R.dimen.FONT_12));
                break;
             case R.dimen.FONT_14:
                textView.setTextSize(resources.getDimension(R.dimen.FONT_14));
                break;
             case R.dimen.FONT_16:
                textView.setTextSize(resources.getDimension(R.dimen.FONT_16));
                break;
             case R.dimen.FONT_18:
                textView.setTextSize(resources.getDimension(R.dimen.FONT_18));
                break;
             case R.dimen.FONT_20:
                textView.setTextSize(resources.getDimension(R.dimen.FONT_20));
                break;
            case R.color.FONT_RED:
                textView.setTextColor(resources.getColor(R.color.FONT_RED));
                break;
            case R.color.FONT_GREEN:
                textView.setTextColor(resources.getColor(R.color.FONT_GREEN));
                break;
            case R.color.FONT_BLUE:
                textView.setTextColor(resources.getColor(R.color.FONT_BLUE));
                break;
        }

        return super.onOptionsItemSelected(item);
    }
}

二、上下文菜单（ContextMenu）

上下文菜单是指当长按某个控件时，所弹出的菜单，其创建步骤为：

1.使用registerForContextMenu为要创建上下文菜单的控件注册

2.在onCreateContextMenu方法中，调用ContextMenu的add方法添加菜单项

3.在onCreateContextMenu方法中，调用MenuItem的getItemId方法获得所选中的菜单，并进行响应。

package com.example.shiyanshi.contextmenu;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView txt;

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

        txt=(TextView)findViewById(R.id.txt);
        registerForContextMenu(txt);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {

        menu.add(0,R.color.BACK_RED,0,"红色");
        menu.add(0,R.color.BACK_GREEN,0,"绿色");
        menu.add(0,R.color.BACK_BLUE,0,"蓝色");
        menu.setHeaderTitle("请选择背景颜色");
        menu.setGroupCheckable(0,true,true);


        super.onCreateContextMenu(menu, v, menuInfo);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.color.BACK_RED:
                txt.setBackgroundColor(MainActivity.this.getResources().getColor(R.color.BACK_RED));
                break;
            case R.color.BACK_GREEN:
                txt.setBackgroundColor(MainActivity.this.getResources().getColor(R.color.BACK_GREEN));
                break;
            case R.color.BACK_BLUE:
                txt.setBackgroundColor(MainActivity.this.getResources().getColor(R.color.BACK_BLUE));
                break;
        }

        return super.onContextItemSelected(item);
    }
}

三、通过xml文件创建菜单

通过xml文件创建菜单项时，只需在上述一二中onCreateOptionsMenu、onCreateContextMenu中创建MenuInflater（或调用getMenuInflater获得），并调用MenuInflater的inflater方法设置菜单项的资源文件。

其中在xml文件中item定义菜单项，其下可以有

<menu xmlns:android="http://schemas.android.com/apk/res/android">

<item>       item用于定义菜单项，其下可以用menu和item结合定义子菜单
    <menu>   menu可以直接接子菜单项item，也可以接group分组后再接item，如下
        <item></item>
        <item></item>
    </menu>        
</item>

</menu>

<item>
    <menu> 
        <group>
            <item></item>
            <item></item>
        </group>           
    </menu>
</item>

1.MainActivity.java

package com.example.shiyanshi.usingxmlcreatemenu;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

public class XmlActivity extends AppCompatActivity {

    private TextView txtOptions;
    private TextView txtContext;

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

        txtOptions=(TextView)findViewById(R.id.txtOptions);
        txtContext=(TextView)findViewById(R.id.txtContext);

        registerForContextMenu(txtContext);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.options_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will

        switch (item.getItemId()){
            case R.id.font10:
                item.setChecked(true);
                txtOptions.setTextSize(getResources().getDimension(R.dimen.FONT_10));
                break;
            case R.id.font12:
                item.setChecked(true);
                txtOptions.setTextSize(getResources().getDimension(R.dimen.FONT_12));
                break;
            case R.id.font14:
                item.setChecked(true);
                txtOptions.setTextSize(getResources().getDimension(R.dimen.FONT_14));
                break;
            case R.id.font16:
                item.setChecked(true);
                txtOptions.setTextSize(getResources().getDimension(R.dimen.FONT_16));
                break;
            case R.id.font18:
                item.setChecked(true);
                txtOptions.setTextSize(getResources().getDimension(R.dimen.FONT_18));
                break;
            case R.id.font20:
                item.setChecked(true);
                txtOptions.setTextSize(getResources().getDimension(R.dimen.FONT_20));
                break;
            case R.id.colorRed:
                item.setChecked(true);
                txtOptions.setTextColor(getResources().getColor(R.color.FONT_RED));
                break;
            case R.id.colorGreen:
                item.setChecked(true);
                txtOptions.setTextColor(getResources().getColor(R.color.FONT_GREEN));
                break;
            case R.id.colorBlue:
                item.setChecked(true);
                txtOptions.setTextColor(getResources().getColor(R.color.FONT_BLUE));
                break;
        }


        return super.onOptionsItemSelected(item);
    }


    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        getMenuInflater().inflate(R.menu.context_menu,menu);

        super.onCreateContextMenu(menu, v, menuInfo);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.contextRed:
                item.setChecked(true);
                txtContext.setBackgroundColor(Color.RED);
                break;
            case R.id.contextGreen:
                item.setChecked(true);
                txtContext.setBackgroundColor(Color.GREEN);
                break;
            case R.id.contextBlue:
                item.setChecked(true);
                txtContext.setBackgroundColor(Color.BLUE);
                break;
        }

        return super.onContextItemSelected(item);
    }

}

2.options_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:id="@+id/fontSize"
        android:title="@string/options_font_title">
        <menu>
            <group android:checkableBehavior="single" >
                <item android:id="@+id/font10"
                    android:title="@string/font10"/>
                <item android:id="@+id/font12"
                    android:title="@string/font12"/>
                <item android:id="@+id/font14"
                    android:title="@string/font14"/>
                <item android:id="@+id/font16"
                    android:title="@string/font16"/>
                <item android:id="@+id/font18"
                    android:title="@string/font18"/>
                <item android:id="@+id/font20"
                    android:title="@string/font20"/>
            </group>
        </menu>

    </item>

    <item android:id="@+id/fontColor"
        android:title="@string/options_color_title">
        <menu >
            <group android:checkableBehavior="single">
                <item android:id="@+id/colorRed"
                    android:title="@string/red"/>
                <item android:id="@+id/colorGreen"
                    android:title="@string/green"/>
                <item android:id="@+id/colorBlue"
                    android:title="@string/blue"/>
            </group>
        </menu>

    </item>
</menu>

3.context_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <group>
        <item android:id="@+id/contextRed"
            android:title="@string/red"/>
        <item android:id="@+id/contextGreen"
            android:title="@string/green"/>
        <item android:id="@+id/contextBlue"
            android:title="@string/blue"/>
    </group>
</menu>

四、弹出菜单（PopupMenu）

弹出菜单是指某个组件被单击后，会在其上方或下方所弹出的菜单其创建步骤：

1.调用new PopupMenu(Context context, View anchor)方法创建弹出式菜单PopupMenu

2.调用MenuInflater的inflater方法将菜单资源添加到菜单

3.通过PopupMenu的setOnMenuItemClickListener方法监视菜单项的状态

4.调用PopupMenu的show方法显示菜单

package com.henry.popupmenu;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.PopupMenu;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private PopupMenu popupMenu=null;

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



        findViewById(R.id.btnPopup).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                popupMenu=new PopupMenu(MainActivity.this,v);
                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.edit:
                                popupMenu.dismiss();
                                break;
                            default:
                                Toast.makeText(MainActivity.this, "您单击了"+ "【"+item.getTitle()+"】", Toast.LENGTH_SHORT).show();
                        }
                        return true;
                    }
                });


                popupMenu.show();


            }
        });
    }


}