public class AreaURL extends Activity implements View.OnClickListener{
Button button1;
private String petrolPriceURL = "http://www.petrolprices.com/feeds/averages.xml?search_type=town&search_value=glasgow";
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.userurldisplay);
button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(this);
public void onClick(View v) {
new AlertDialog.Builder(Area.this)
.setTitle("Confirm")
.setMessage("Is this the XML feed you require?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// continue
TestMethod();
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// do nothing
}
})
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
public void TestMethod(){
EditText mEdit;
EditText mEdit2;
String newFirstString = petrolPriceURL.substring(0,59);
String newSecondString = petrolPriceURL.substring(63,77);
mEdit = (EditText)findViewById(R.id.editText1);
mEdit.getText().toString();
mEdit2 = (EditText)findViewById(R.id.editText2);
mEdit2.getText().toString();
String newThirdString = newFirstString + mEdit.getText().toString();
String newFourthString = newSecondString + mEdit2.getText().toString();
String newFifthString = newThirdString + newFourthString;
Intent intent=new Intent(this,PetrolPriceActivity.class);
intent.putExtra("URLString",newFifthString);
startActivity(intent);
}
}
Intent intent=new Intent(this,PetrolPriceActivity.class);
intent.putExtra("URLString",newFifthString);
startActivity(intent);
}
}
response = (TextView)findViewById(R.id.textView2);
response.setText(newFifthString);
08-0712:11:44.453:I/Choreographer(1257):跳过126帧!
应用程序可能在主线程上做了太多工作。08-07 12:11:46.313:I/Choreographer(1257):跳过了131帧!
应用程序可能在主线程上做了太多工作。08-07 12:11:48.033:I/Choreographer(1257):跳过了33个帧!
应用程序可能在主线程上做了太多的工作。08-07 12:11:51.753:D/DALVIKVM(1257):GC_FOR_ALLOC释放137K,6%空闲3938K/4152K,暂停146ms,总计146ms08-07 12:11:52.003:D/AndroidRuntime(1257):关闭VM08-07 12:11:52.003:W/DALVIKVM(1257):thread=1:线程退出未捕获异常(组=0xB3A96BA8)08-07 12:11:52.063:E/AndroidRuntime(1257):致命异常:main 08-07 12:11:52.063:E/AndroidRuntime(1257):main):进程:org.me.myandroidstuff,PID:1257 08-07 12:11:52.063:e/androidruntime(1257):java.lang.runtimeException:无法启动活动ComponentInfo{org.me.myandroidstuft/org.me.myandroidstuff.petrolpriceactivity}:java.lang.nullpointerException 08-07 12:11:52.063:e/androidruntime(1257):at eLaunchActivity(ActivityThread.java:2245)08-07 12:11:52.063:e/AndroidRuntime(1257):at Android.app.ActivityThread.Access$800(ActivityThread.java:135)08-07 12:11:52.063:e/AndroidRuntime(1257):at Android.app.ActivityThread$H.HandleMessage(ActivityThread.java:1196)08-07 12:11:52.063:e/AndroidRuntime(1257):at Android.os.handler.dispatchMessage(handler.java:102)08-07 12:11:52.063:e/AndroidRuntime(1257):at Android.os.looper.loop(looper.java:136)08-07)08-07 12:11:52.063:e/AndroidRuntime(1257):at java.lang.reflect.Method.invokenative(本机方法)08-07 12:11:52.063:e/AndroidRuntime(1257):at java.lang.reflect.Method.invoke(515):at java.lang.reflect.Method.invoke(1257):at Method.java:515)08-07 12:11:52.063:e/AndroidRuntime(1257):at goteinit.main(zygoteinit.java:595)08-07 12:11:52.063:e/AndroidRuntime(1257):at dalvik.system.nativeStart.main(本机方法)08-07 12:11:52.063:e/AndroidRuntime(1257):by:java.lang.NullPointer异常08-07 12:11:52.063:e/AndroidRuntime(1257):at org.me.myAndroidStuff.petrolpriceActivity.onCreate(petrolpriceActivity.java:53)08-07 12:11:52.063:e/AndroidRuntime(1257):at Android.app.activity.performCreate(activity.java:53)08-07 12:11:52.063:e/AndroidRuntime(1257):at Android.app.activity.5231):at ythread.performLaunchActivity(activitythread.java:2159)08-07 12:11:52.063:e/AndroidRuntime(1257):...11更多
我的xml布局
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="invisible"
android:text="@string/thank_you" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView2"
android:layout_toRightOf="@+id/textView2"
android:background="#CCCCCC"
android:ems="10"
android:inputType="textPersonName" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView2"
android:layout_toRightOf="@+id/textView2"
android:background="#CCCCCC"
android:ems="10"
android:inputType="textPersonName" >
<requestFocus />
</EditText>
<Button
android:id="@+id/button1"
android:layout_width="214dp"
android:layout_height="wrap_content"
android:text="@string/OK" />
这是我的PetrolPriceActivity课
package org.me.myandroidstuff;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class PetrolPriceActivity extends Activity
{
private TextView response;
private TextView errorText;
private String result;
private String petrolPriceURL;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.list);
Bundle extras = getIntent().getExtras();
if(extras!=null){
petrolPriceURL =extras.getString("URLString");
}
// Get the TextView object on which to display the results
response = (TextView)findViewById(R.id.title);
try
{
// Get the data from the RSS stream as a string
result = petrolPriceString(petrolPriceURL);
// Do some processing of the data to get the individual parts of the RSS stream
// At some point put this processing into a separate thread of execution
// Display the string in the TextView object just to demonstrate this capability
// This will need to be removed at some point
response.setText(result);
}
catch(IOException ae)
{
// Handle error
response.setText("Error");
// Add error info to log for diagnostics
errorText.setText(ae.toString());
}
}
// End of onCreate
// Method to handle the reading of the data from the RSS stream
private static String petrolPriceString(String urlString)throws IOException
{
String result = "";
InputStream anInStream = null;
int response = -1;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
// Check that the connection can be opened
if (!(conn instanceof HttpURLConnection))
throw new IOException("Not an HTTP connection");
try
{
// Open connection
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("GET");
httpConn.connect();
response = httpConn.getResponseCode();
// Check that connection is Ok
if (response == HttpURLConnection.HTTP_OK)
{
// Connection is OK so open a reader
anInStream = httpConn.getInputStream();
InputStreamReader in= new InputStreamReader(anInStream);
BufferedReader bin= new BufferedReader(in);
// Read in the data from the RSS stream
String line = new String();
while (( (line = bin.readLine())) != null)
{
result = result + "\n" + line;
}
}
}
catch (Exception ex)
{
throw new IOException("Error connecting");
}
// Return result as a string for further processing
return result;
}
// End of petrolPriceString
// End of Activity class
}
错误是
errorText.setText(ae.toString());
您没有初始化该变量。
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.list);
//////////////////////////////////////////////////////Solution
errorText = (TextView)findViewById(R.id.yourTextView);
Bundle extras = getIntent().getExtras();
if(extras!=null){
petrolPriceURL =extras.getString("URLString");
}
// Get the TextView object on which to display the results
response = (TextView)findViewById(R.id.title);
try
{
// Get the data from the RSS stream as a string
result = petrolPriceString(petrolPriceURL);
// Do some processing of the data to get the individual parts of the RSS stream
// At some point put this processing into a separate thread of execution
// Display the string in the TextView object just to demonstrate this capability
// This will need to be removed at some point
response.setText(result);
}
catch(IOException ae)
{
// Handle error
response.setText("Error");
// Add error info to log for diagnostics
errorText.setText(ae.toString()); //////////This variable is not intialized.
}
}
有时,当我试图创建模糊位图时,我会遇到“空指针异常”。 发生在这段代码中(我最近开始捕获异常,因此至少它不会使应用程序崩溃): 请参考这些图片以获得更多关于我传递给“CreateBitmap”方法的参数的细节: 以下是扩展的参数: 完全异常: 异常{Java。Lang.NullPointerException:类型为“Java”的异常。引发了“Lang.NullPointerException”。
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