实例HelloTimePicker

范例HelloTimePicker
Android docs中的范例，简单翻译整理如下。
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1、创建新项目，名称HelloTimePicker；

2、修改res/layout/main.xml，内容如下：

<?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/timeDisplay"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text=""/>    <Button android:id="@+id/pickTime"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Change the time"/></LinearLayout>

3、修改HelloTimePicker.java，增加成员变量定义，代码如下：

    private TextView mTimeDisplay;    private Button mPickTime;    private int mHour;    private int mMinute;    static final int TIME_DIALOG_ID = 0;

4、修改HelloTimePicker.java的onCreate方法，内容如下：

    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        // capture our View elements        mTimeDisplay = (TextView) findViewById(R.id.timeDisplay);        mPickTime = (Button) findViewById(R.id.pickTime);        // add a click listener to the button        mPickTime.setOnClickListener(new View.OnClickListener() {            public void onClick(View v) {                showDialog(TIME_DIALOG_ID);            }        });        // get the current time        final Calendar c = Calendar.getInstance();        mHour = c.get(Calendar.HOUR_OF_DAY);        mMinute = c.get(Calendar.MINUTE);        // display the current date        updateDisplay();    }

5、修改HelloTimePicker.java增加updateDisplay和pad方法，内容如下：

// updates the time we display in the TextViewprivate void updateDisplay() {    mTimeDisplay.setText(        new StringBuilder()                .append(pad(mHour)).append(":")                .append(pad(mMinute)));}private static String pad(int c) {    if (c >= 10)        return String.valueOf(c);    else        return "0" + String.valueOf(c);}

6、修改HelloTimePicker.java增加时间选择对话框，内容如下：

    // the callback received when the user "sets" the time in the dialog    private TimePickerDialog.OnTimeSetListener mTimeSetListener =        new TimePickerDialog.OnTimeSetListener() {            public void onTimeSet(TimePicker view, int hourOfDay, int minute) {                mHour = hourOfDay;                mMinute = minute;                updateDisplay();            }        };

7、修改HelloTimePicker.java增加onCreateDialog方法，内容如下：

@Overrideprotected Dialog onCreateDialog(int id) {    switch (id) {    case TIME_DIALOG_ID:        return new TimePickerDialog(this,                mTimeSetListener, mHour, mMinute, false);    }    return null;}

8、运行项目，即可看到运行效果，如下图所示：

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