尝试创建一个简单的时间选择器来填充按钮时，我在下面遇到了这段代码，似乎是我在寻找的东西-但在运行时崩溃。你们可以指出问题还是提供更好的代码。提前致谢。
<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:padding="16dp"
tools:context=".MainActivity"
>
<TextView
android:id="@+id/tv"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
/>
<Button
android:id="@+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onButtonClicked"
android:text="Set Time"
android:layout_below="@id/tv"
/>
</RelativeLayout>
这是代码
package com.example.xxxx;
import android.app.AlertDialog;
import android.app.TimePickerDialog;
import android.graphics.Color;
import android.os.Bundle;
import android.app.Fragment;
import android.text.format.DateFormat;
import android.view.Gravity;
import android.widget.TextView;
import android.app.DialogFragment;
import android.app.Dialog;
import java.util.Calendar;
import android.widget.TimePicker;
/**
* A simple {@link Fragment} subclass.
*/
public class MainActivity extends DialogFragment implements TimePickerDialog.OnTimeSetListener{
@Override
public Dialog onCreateDialog(Bundle savedInstanceState){
//Use the current time as the default values for the time picker
final Calendar c = Calendar.getInstance();
int hour = c.get(Calendar.HOUR_OF_DAY);
int minute = c.get(Calendar.MINUTE);
//Create and return a new instance of TimePickerDialog
/*
public constructor.....
TimePickerDialog(Context context, int theme,
TimePickerDialog.OnTimeSetListener callBack, int hourOfDay, int minute, boolean is24HourView)
The 'theme' parameter allow us to specify the theme of TimePickerDialog
.......List of Themes.......
THEME_DEVICE_DEFAULT_DARK
THEME_DEVICE_DEFAULT_LIGHT
THEME_HOLO_DARK
THEME_HOLO_LIGHT
THEME_TRADITIONAL
*/
TimePickerDialog tpd = new TimePickerDialog(getActivity(), AlertDialog.THEME_DEVICE_DEFAULT_DARK
,this, hour, minute, DateFormat.is24HourFormat(getActivity()));
//You can set a simple text title for TimePickerDialog
//tpd.setTitle("Title Of Time Picker Dialog");
/*.........Set a custom title for picker........*/
TextView tvTitle = new TextView(getActivity());
tvTitle.setText("TimePickerDialog Title");
tvTitle.setBackgroundColor(Color.parseColor("#EEE8AA"));
tvTitle.setPadding(5, 3, 5, 3);
tvTitle.setGravity(Gravity.CENTER_HORIZONTAL);
tpd.setCustomTitle(tvTitle);
/*.........End custom title section........*/
return tpd;
}
//onTimeSet() callback method
public void onTimeSet(TimePicker view, int hourOfDay, int minute){
//Do something with the user chosen time
//Get reference of host activity (XML Layout File) TextView widget
TextView tv = (TextView) getActivity().findViewById(R.id.tv);
//Set a message for user
//Get the AM or PM for current time
String aMpM = "AM";
if(hourOfDay >11)
{
aMpM = "PM";
}
//Make the 24 hour time format to 12 hour time format
int currentHour;
if(hourOfDay>11)
{
currentHour = hourOfDay - 12;
}
else
{
currentHour = hourOfDay;
}
tv.setText("Your chosen time is...\n\n");
//Display the user changed time on TextView
tv.setText(tv.getText()+ String.valueOf(currentHour)
+ " : " + String.valueOf(minute) + " " + aMpM + "\n");
}
错误记录
02-17 08:58:46.497: E/AndroidRuntime(21811): FATAL EXCEPTION: main
02-17 08:58:46.497: E/AndroidRuntime(21811): Process: com.example.xxxx, PID: 21811
02-17 08:58:46.497: E/AndroidRuntime(21811): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.xxxx/com.example.xxxx.MainActivity}: java.lang.ClassCastException: com.example.xxxx.MainActivity cannot be cast to android.app.Activity
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3093)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.ActivityThread.access$1100(ActivityThread.java:221)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.os.Handler.dispatchMessage(Handler.java:102)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.os.Looper.loop(Looper.java:158)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.ActivityThread.main(ActivityThread.java:7224)
02-17 08:58:46.497: E/AndroidRuntime(21811): at java.lang.reflect.Method.invoke(Native Method)
02-17 08:58:46.497: E/AndroidRuntime(21811): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
02-17 08:58:46.497: E/AndroidRuntime(21811): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
02-17 08:58:46.497: E/AndroidRuntime(21811): Caused by: java.lang.ClassCastException: com.example.xxxx.MainActivity cannot be cast to android.app.Activity
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.Instrumentation.newActivity(Instrumentation.java:1095)
02-17 08:58:46.497: E/AndroidRuntime(21811): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3083)
02-17 08:58:46.497: E/AndroidRuntime(21811): ... 9 more
最佳答案
为此使用自定义布局。您必须在其中按下以下按钮：time_picker_dialod.xml
<?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"
android:orientation="vertical"
android:background="@color/accentcolor"
android:padding="8dp">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@+id/date_time_set">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="10dp"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="Select Time"
android:textSize="14sp"
android:textStyle="bold" />
<TimePicker
android:id="@+id/time_picker"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</ScrollView>
<Button
android:id="@+id/date_time_set"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="Set Time" />
</RelativeLayout>
现在，您可以在对话框中使用此布局，如下所示
ProgressDialog progressDialog = new ProgressDialog(Add_ReminderActivity.this);
progressDialog.setMessage("Please wait.");
progressDialog.show();
final View dialogView = View.inflate(Add_ReminderActivity.this, R.layout.time_picker_dialod, null);
final AlertDialog alertDialog = new AlertDialog.Builder(Add_ReminderActivity.this).create();
alertDialog.setView(dialogView);
final TimePicker timePicker = (TimePicker) dialogView.findViewById(R.id.time_picker);
if (Build.VERSION.SDK_INT >= 23) {
timePicker.setHour(00);
timePicker.setMinute(00);
} else {
timePicker.setCurrentHour(00);
timePicker.setCurrentMinute(00);
}
dialogView.findViewById(R.id.date_time_set).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (Build.VERSION.SDK_INT >= 23) {
Selected_From_Time = Uri.encode(DigitPad(timePicker.getHour()) + ":" + DigitPad(timePicker.getMinute()) + ":" + "00");
} else {
Selected_From_Time = Uri.encode(DigitPad(timePicker.getCurrentHour()) + ":" + DigitPad(timePicker.getCurrentMinute()) + ":" + "00");
}
alertDialog.dismiss();
}
});
alertDialog.show();
if (alertDialog.isShowing()) {
progressDialog.dismiss();
}
DigitPad功能：
public String DigitPad(int myNumber) {
String mNumber = String.valueOf(myNumber);
return (mNumber.toString().length() < 2) ? "0" + mNumber : mNumber;
}
希望这对您有帮助