Eclipse 开发 Android, Hello, DatePicker （学习7）

最新推荐文章于 2023-02-28 10:22:52 发布

最新推荐文章于 2023-02-28 10:22:52 发布 · 176 阅读

文章标签：

#Android #Eclipse #C #C++ #C#

Android 专栏收录该内容

11 篇文章

订阅专栏

本文介绍了一个简单的Android应用HelloDatePicker的实现过程，通过该应用可以学习如何使用DatePicker组件选择日期，并在TextView中显示所选日期。

Hello, DatePicker

Start a new project/Activity called HelloDatePicker.

创建工程 HelloDatePicker，修改如下代码。

HelloDatePicker.java 代码

package com.example.test;

import java.util.Calendar;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;

public class HelloDatePicker extends Activity {
	
	private TextView mDateDisplay;
    private Button mPickDate;

    private int mYear;
    private int mMonth;
    private int mDay;

    static final int DATE_DIALOG_ID = 0;

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

        // capture our View elements
        mDateDisplay = (TextView) findViewById(R.id.dateDisplay);
        mPickDate = (Button) findViewById(R.id.pickDate);

        // add a click listener to the button
        mPickDate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDialog(DATE_DIALOG_ID);
            }
        });

        // get the current date
        final Calendar c = Calendar.getInstance();
        mYear = c.get(Calendar.YEAR);
        mMonth = c.get(Calendar.MONTH);
        mDay = c.get(Calendar.DAY_OF_MONTH);

        // display the current date
        updateDisplay();
    }
    
    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case DATE_DIALOG_ID:
            return new DatePickerDialog(this,
                        mDateSetListener,
                        mYear, mMonth, mDay);
        }
        return null;
    }
    
    // updates the date we display in the TextView
    private void updateDisplay() {
        mDateDisplay.setText(
            new StringBuilder()
                    // Month is 0 based so add 1
                    .append(mMonth + 1).append("-")
                    .append(mDay).append("-")
                    .append(mYear).append(" "));
    }

    // the callback received when the user "sets" the date in the dialog
    private DatePickerDialog.OnDateSetListener mDateSetListener =
        new DatePickerDialog.OnDateSetListener() {

            public void onDateSet(DatePicker view, int year, 
                                  int monthOfYear, int dayOfMonth) {
                mYear = year;
                mMonth = monthOfYear;
                mDay = dayOfMonth;
                updateDisplay();
            }
    };
    
}

Layout->main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView android:id="@+id/dateDisplay"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text=""/>

    <Button android:id="@+id/pickDate"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Change the date"/>

</LinearLayout>

运行 Eclipse -> HelloDatePicker->Run as->Android Application 运行界面如下：