Android 当我尝试插入日期和时间选择器时，为什么我的应用程序不断崩溃？
我是一个android新手，一般来说，我都是编程新手。我正试图在我的代码中插入一个android时间和日期选择器，但当我尝试这样做时，它总是崩溃。谁能帮帮我吗Android 当我尝试插入日期和时间选择器时，为什么我的应用程序不断崩溃？,android,datepicker,Android,Datepicker,我是一个android新手，一般来说，我都是编程新手。我正试图在我的代码中插入一个android时间和日期选择器，但当我尝试这样做时，它总是崩溃。谁能帮帮我吗 public class NewEvent extends Activity { private static int RESULT_LOAD_IMAGE = 1; private EventHandler handler; private String picture
public class NewEvent extends Activity {
private static int RESULT_LOAD_IMAGE = 1;
private EventHandler handler;
private String picturePath = "";
private String name;
private String place;
private String date;
private String time;
private String photograph;
DatePicker datepicker; // object for datepicker
int year , month , day; // declaring variables for year, month and day
TimePicker timepicker; // object for timepicker
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_event);
handler = new EventHandler(getApplicationContext());
//datepicker = (DatePicker) findViewById(R.id.datePicker); // Obtain datepicker attributes from layout
//timepicker = (TimePicker) findViewById(R.id.timePicker); //Obtain timepicker attributes from layout
timepicker.setIs24HourView(true); //setting timepicker to 24 hr clock view
Button button = (Button) findViewById(R.id.button1); // button to display datepicker value
Button button1 = (Button) findViewById(R.id.button2); // button to display timepicker value
ImageView iv_user_photo = (ImageView) findViewById(R.id.iv_user_photo);
iv_user_photo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, RESULT_LOAD_IMAGE);
}
});
Button btn_add = (Button) findViewById(R.id.btn_add);
btn_add.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
EditText et_name = (EditText) findViewById(R.id.et_name);
name = et_name.getText().toString();
EditText et_place = (EditText) findViewById(R.id.et_place);
place = et_place.getText().toString();
EditText et_date = (EditText) findViewById(R.id.et_date);
date = et_date.getText().toString();
EditText et_time = (EditText) findViewById(R.id.et_time);
time = et_time.getText().toString();
ImageView iv_photograph = (ImageView) findViewById(R.id.iv_user_photo);
photograph = picturePath;
Event event = new Event();
event.setName(name);
event.setPlace(place);
event.setDate(date);
event.setTime(time);
event.setPhotograph(photograph);
Boolean added = handler.addEventDetails(event);
if(added){
Intent intent = new Intent(NewEvent.this, MainEvent.class);
startActivity(intent);
}else{
Toast.makeText(getApplicationContext(), "Event data not added. Please try again", Toast.LENGTH_LONG).show();
}
}
});
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// displaying datepicker value as pop up notification
Toast.makeText(getBaseContext(), "Date : "
+ (datepicker.getMonth() + 1) +"/"+datepicker.getDayOfMonth()
+"/"+datepicker.getYear(), Toast.LENGTH_LONG).show(); }
});
// On clicking button start timepicker event
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// displaying timepicker value as pop up notification
Toast.makeText(getBaseContext(),"Time Selected : "+timepicker.getCurrentHour()+":"
+timepicker.getCurrentMinute(), Toast.LENGTH_SHORT).show();
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
Uri imageUri = data.getData();
String[] filePathColumn = { MediaStore.Images.Media.DATA };
Cursor cursor = getContentResolver().query(imageUri,
filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
picturePath = cursor.getString(columnIndex);
cursor.close();
ImageView imageView = (ImageView) findViewById(R.id.iv_user_photo);
imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));
}
}
}
<?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:padding="10dp">
<TextView
android:id="@+id/tv_new_event_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add New Event"
android:textAppearance="?android:attr/textAppearanceLarge"
android:layout_alignParentTop="true" />
<Button
android:id="@+id/btn_add"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add Event"
android:layout_alignParentBottom="true" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@id/tv_new_event_title"
android:layout_above="@id/btn_add">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:id="@+id/iv_user_photo"
android:src="@drawable/add_user_icon"
android:layout_width="100dp"
android:layout_height="100dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Event:" />
<EditText
android:id="@+id/et_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text" >
<requestFocus />
</EditText>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Place:" />
<EditText
android:id="@+id/et_place"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text" >
<requestFocus />
</EditText>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Date:" />
<EditText
android:id="@+id/et_date"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="date" />
<Button
android:id="@+id/button"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
<requestFocus />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Time:" />
<EditText
android:id="@+id/et_time"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="time" />
<Button
android:id="@+id/button1"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button1" />
<requestFocus />
</LinearLayout>
</ScrollView>
</RelativeLayout>
在OnCreate方法中执行以下操作： DatePicker dt=（DatePicker）findViewById（R.id.yourDatePickerId）
正如Anuj所说，您需要在使用它之前初始化它您的计时器选择器为空。请初始化它。嗨，阿努伊·夏玛，谢谢你这么快回复我。通过初始化我的时间选择器，你的意思是这样做：TimePicker TimePicker=1；
08-25 11:57:44.144: E/AndroidRuntime(554): FATAL EXCEPTION: main
08-25 11:57:44.144: E/AndroidRuntime(554): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.chris.hockeymanagemtapp/com.chris.hockeymanagemtapp.NewEvent}: java.lang.NullPointerException
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.os.Handler.dispatchMessage(Handler.java:99)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.os.Looper.loop(Looper.java:123)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-25 11:57:44.144: E/AndroidRuntime(554): at java.lang.reflect.Method.invokeNative(Native Method)
08-25 11:57:44.144: E/AndroidRuntime(554): at java.lang.reflect.Method.invoke(Method.java:507)
08-25 11:57:44.144: E/AndroidRuntime(554): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-25 11:57:44.144: E/AndroidRuntime(554): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-25 11:57:44.144: E/AndroidRuntime(554): at dalvik.system.NativeStart.main(Native Method)
08-25 11:57:44.144: E/AndroidRuntime(554): Caused by: java.lang.NullPointerException
08-25 11:57:44.144: E/AndroidRuntime(554): at com.chris.hockeymanagemtapp.NewEvent.onCreate(NewEvent.java:60)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-25 11:57:44.144: E/AndroidRuntime(554): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
08-25 11:57:44.144: E/AndroidRuntime(554): ... 11 more