我试图从用户输入派生的字符串中删除所有空格,但由于某种原因它不适合我.这是我的代码.
public void onClick(View src) {
switch (src.getId()) {
case R.id.buttonGo:
String input = EditTextinput.getText().toString();
input = String.replace(" ", "");
url = ur + input + l;
Intent myIntent = new Intent(start.this, Main.class);
myIntent.putExtra("URL", url);
start.this.startActivity(myIntent);
break;
}
}
我是一名新的Android程序员,最近,我的很多项目都收到了这个错误:
07-31 23:45:19.592: ERROR/AndroidRuntime(716): java.lang.RuntimeException: Unable to start
activity ComponentInfo{com.amrit.musifind/com.amrit.musifind.Main}:
java.lang.NullPointerException
任何人都可以帮我解决这个问题吗？
这是整个logcat堆栈跟踪:
07-31 23:45:18.512: INFO/ActivityManager(63): Starting activity: Intent {
act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000
cmp=com.amrit.musifind/.Main }
07-31 23:45:18.682: INFO/ActivityManager(63): Start proc com.amrit.musifind for activity
com.amrit.musifind/.Main: pid=716 uid=10025 gids={3003}
07-31 23:45:18.962: INFO/jdwp(716): received file descriptor 20 from ADB
07-31 23:45:19.102: DEBUG/ddm-heap(716): Got feature list request
07-31 23:45:19.572: DEBUG/AndroidRuntime(716): Shutting down VM
07-31 23:45:19.572: WARN/dalvikvm(716): threadid=3: thread exiting with uncaught
exception (group=0x4001aa28)
07-31 23:45:19.572: ERROR/AndroidRuntime(716): Uncaught handler: thread main exiting due
to uncaught …我正在开发一个ActiveAdmin应用程序,我希望按照"类型"对一列业务进行排序.不幸的是我的代码无效.我应该用什么代码来完成这个？这是我的代码......
app/models/business.rb
class Business < ActiveRecord::Base
belongs_to :type
attr_accessible :description, :email, :facebook, :foursquare, :google, :manager,
:mobile, :name, :phone, :type_id, :url, :yelp
end
app/models/type.rb
class Type < ActiveRecord::Base
attr_accessible :category
has_many :businesses
def to_s
category
end
end
app/admin/businesses.rb
ActiveAdmin.register Business, { :sort_order => :name_asc } do
scope :joined, :default => true do |businesses|
businesses.includes [:type]
end
index do
column :name
column :type, :sortable => 'businesses.type'
column :manager
column :email
default_actions
end
end
谢谢!
有人可以告诉我如何禁用Android中的按钮,除非所有三个editText字段都填满了吗？我不知道在这里包含条件语句的位置以及如何将它放在按钮侦听器的上下文中.
这是我的主要活动代码.
package com.amritayalur.mypowerschool;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MyPowerSchoolActivity extends Activity {
Button buttonSubmit;
TextView textViewTitle;
TextView textViewDesc;
EditText editTextURL, editTextUser, editTextPass;
String url = "";
String str;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
buttonSubmit = (Button) findViewById(R.id.buttonSubmit);
textViewTitle = (TextView) findViewById(R.id.textViewTitle);
textViewDesc = (TextView) findViewById(R.id.textViewDesc);
editTextURL = (EditText) …我想存储三个字符串作为我的应用程序的用户首选项.我已经设置了一个很好的布局,只需将字符串保存到SharedPreferences即可.我还想知道如何在下一个活动中检索这些字符串.下面是我目前的代码,如果有人能告诉我如何将这个功能添加到代码中,我将不胜感激.这是我的应用程序中的障碍,我一直试图过去几天.
主要活动代码:
package com.amritayalur.mypowerschool;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MyPowerSchoolActivity extends Activity {
Button buttonSubmit;
TextView textViewTitle;
TextView textViewDesc;
EditText editTextURL, editTextUser, editTextPass;
String str;
String username;
String password;
String url;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
buttonSubmit = (Button) findViewById(R.id.buttonSubmit);
textViewTitle = (TextView) findViewById(R.id.textViewTitle);
textViewDesc = (TextView) findViewById(R.id.textViewDesc);
editTextURL …我有一个应用程序,我从URL解析.txt文件并将字符串吐出给用户.我想删除字符串的前16个字符.我怎样才能做到这一点？
编辑 - 我想从我的http调用中收到的数据中删除16个字符.
public void onClick(View src) {
switch(src.getId()) {
case R.id.buttonRetrieveMetar:
InputMethodManager imm = (InputMethodManager)
getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(EditTextAirportCode.getWindowToken(), 0);
textDisplayMetar.setText ("");
airportcode = EditTextAirportCode.getText().toString();
url = urlmetar + airportcode + ".TXT";
//Added 06-27-11 METAR code
textDisplayMetar.setText ("");
try {
HttpGet httpGet = new HttpGet(url);
HttpClient httpclient = new DefaultHttpClient();
// Execute HTTP Get Request
HttpResponse response = httpclient.execute(httpGet);
content = response.getEntity().getContent();
BufferedReader r = new BufferedReader(new
InputStreamReader(content));
StringBuilder total = new StringBuilder();
String line;
while ((line = r.readLine()) != …我正在寻找一些源代码或示例代码,详细说明如何在Android中显示加速度计的值.优选地,这些值将显示x方向,y方向和z方向上的加速度.
我是一个Android noob,所以任何帮助都非常感谢.
我正在尝试将三个字符串永久存储为我的 Android 应用程序的用户首选项。这三个字符串是 url、用户名和密码。我不太了解 SharedPreferences，所以我尝试使用内部文件存储。我无法从文件中检索三个字符串，并且出现运行时错误。我知道我可能编码有误，但我对 Android 不够精通，无法理解数据存储。有人可以帮我吗？
偏好活动：
package com.amritayalur.mypowerschool;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MyPowerSchoolActivity extends Activity {
Button buttonSubmit;
TextView textViewTitle;
TextView textViewDesc;
EditText editTextURL, editTextUser, editTextPass;
FileOutputStream fos;
String url = "";
String FILENAME = "InternalStrings";
String str;
String username;
String password;
/** Called when the activity is first created. */
@Override …我有一个Rails部分,当我点击部分中的按钮时,我想运行一个Ruby脚本.
我该怎么做呢？
这是我想要运行的脚本 - 我现在在<%= %>标签中有它.
<%= require 'nokogiri'
doc = Nokogiri::HTML(table_string)
doc.xpath('//table//tr').each do |row|
row.xpath('td').each do |cell|
print '"', cell.text.gsub("\n", ' ').gsub('"', '\"').gsub(/(\s){2,}/m, '\1'), "\", "
end
print "\n"
end
%>
我希望有一个按钮,当我点击它时运行该片段.