5.2 Android Basic QuickStart Widgets&Other View Time Picker

Time Picker

演练时间选择控件。

在本教程中当用户单击按钮后我们将创建TimePickerDialog。从对话框选择的时间将被更新到TextView中。

新建项目HelloTimePicker。

打开res/layout/main.xml使用下面的代码:
<?xml version="1.0" encoding="utf-8"?>

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

android:orientation="vertical"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

>

<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. 打开HelloTimePicker.java 创建成员变量:

private TextView mTimeDisplay;

private Button mPickTime;

private int mHour;

private int mMinute;

static final int TIME_DIALOG_ID=0;

4. 修改OnCreate()方法的代码:

@Override

public 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() {

@Override

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);

// dispaly the current date

updateDisplay();

}

5. 增加updateDisplay()方法和pad()方法:

//update the time we display in the Textview

private 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. 增加一个TimePickerDialog.OnTimeSetListener的成员，当用户设置新的时间时被调用：

//the callback received when the user 'sets' the time in the dialog

private TimePickerDialog.OnTimeSetListener mTimeSetListener=

new TimePickerDialog.OnTimeSetListener() {

@Override

public void onTimeSet(TimePicker view, int hourOfDay, int minute) {

// TODO Auto-generated method stub

mHour = hourOfDay;

mMinute=minute;

updateDisplay();

}

};

7. 添加onCreateDialog(int)回调方法：

@Override

protected Dialog onCreateDialog(int id) {

// TODO Auto-generated method stub

switch(id){

case TIME_DIALOG_ID:

return new TimePickerDialog(this,

mTimeSetListener,mHour,mMinute,false);

}

return null;

}

8. 运行应用程序



author: im@xingquan.org