第五次作业

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.homework3.MainActivity" >

    <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="212dp"
        android:text="请选择颜色" />

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="92dp"
        android:text="计算机1702辛锋"
        android:textSize="20sp" />

</RelativeLayout>

package com.example.homework5;
import android.support.v7.app.ActionBarActivity;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity implements OnClickListener{
	 String[] a = {"#FFFF00", "#0000FF", "#FF0000", "#00FF00", "#9900CC"};
	    int color = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //设置Button监听事件
        Button btn=(Button)findViewById(R.id.bt);
        btn.setOnClickListener(this);
        
    }
    @Override
    public void onClick(View v) {
    	
    	AlertDialog dialog;
        AlertDialog.Builder builder = new AlertDialog.Builder(this)
                .setTitle("选择背景颜色")           //设置标题
                .setIcon(R.drawable.ic_launcher)
                .setSingleChoiceItems(new String[]{ "黄色", "蓝色", "红色","绿色", "紫色"}, color, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        // 点单选按钮时发生的事件，这里which表示你点的单选按钮是第几个
                        color = which;
                    }
                })
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        //点确定按钮时发生的事件
                    	TextView tv=(TextView) findViewById(R.id.tv);               	
                       tv.setBackgroundColor(Color.parseColor(a[color]));
                       //String类型的颜色值转换成Int类型的颜色值
                        dialog.dismiss();
                    }
                })//添加“确定”按钮
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // 点取消按钮发生的事件
                        dialog.dismiss();
                    }
                });
        dialog = builder.create();
        dialog.show();
    }
}