<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item android:id="@+id/blue" android:title="蓝色"  app:showAsAction="never"></item>
    <item android:id="@+id/red" android:title="红色" > </item>
    <item android:id="@+id/green" android:title="绿色" ></item>
</menu>

代码

package com.example.zuoye01;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
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=findViewById(R.id.textview);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity,menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id=item.getItemId();
        switch (id){
            case R.id.blue:
                textView.setTextColor(Color.parseColor("#2239A2"));
                break;
            case R.id.green:
                textView.setTextColor(Color.parseColor("#1BA233"));
                break;
            case R.id.red:
                textView.setTextColor(Color.parseColor("#A21C31"));
                break;
        }
        return super.onOptionsItemSelected(item);
    }
}

自定义Dialog

   MyDialog myDialog = new MyDialog(MainActivity.this);
                myDialog.show();
                Window window = myDialog.getWindow();
                WindowManager.LayoutParams lp = window.getAttributes();
                lp.width=600;
                lp.height=1000;
                window.setAttributes(lp);

package com.example.day01;

import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.Toast;

public class MyDataDialog extends Dialog {
    Context context;
    public MyDataDialog(Context context) {
        super(context);
        this.context = context;
    }
    private DatePicker dp;
    private Button queding;
    private Button quxiao;
//onCreate()，show()，onStart() ，cancel()，onDismiss()，Stop()
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.mydata);
//        setCanceledOnTouchOutside(false);
        dp=findViewById(R.id.data_picker);
        queding = findViewById(R.id.queding);
        quxiao=findViewById(R.id.quxiao);
        queding.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(context,dp.getYear()+"年"+(dp.getMonth()+1)+"月",Toast.LENGTH_SHORT).show();
                MyDataDialog.this.dismiss();
            }
        });
        quxiao.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(context,"取消",Toast.LENGTH_SHORT);
                MyDataDialog.this.dismiss();
            }
        });
    }



}

布局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
   >
<DatePicker
    android:id="@+id/data_picker"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
</DatePicker>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/data_picker"
        android:layout_alignRight="@id/data_picker"
        android:orientation="horizontal">
        <Button
            android:id="@+id/queding"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@null"
            android:layout_weight="1"
            android:text="确定"/>
        <Button
            android:id="@+id/quxiao"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@null"
            android:layout_weight="1"
            android:text="取消"/>
    </LinearLayout>
</RelativeLayout>