我正在尝试使用php创建我的第一个Android应用，但我在开始时遇到了一些困难。
当我运行我的代码时，我收到此错误日志：
12-07 19:34:22.095: D/AndroidRuntime(13777): Shutting down VM
12-07 19:34:22.095: W/dalvikvm(13777): threadid=1: thread exiting with uncaught exception (group=0x42300c08)
12-07 19:34:22.095: E/AndroidRuntime(13777): FATAL EXCEPTION: main
12-07 19:34:22.095: E/AndroidRuntime(13777): Process: com.example.parents_gps, PID: 13777
12-07 19:34:22.095: E/AndroidRuntime(13777): java.lang.NullPointerException
12-07 19:34:22.095: E/AndroidRuntime(13777): at com.example.parents_gps.MainActivity$1.onClick(MainActivity.java:42)
12-07 19:34:22.095: E/AndroidRuntime(13777): at android.view.View.performClick(View.java:4633)
12-07 19:34:22.095: E/AndroidRuntime(13777): at android.view.View$PerformClick.run(View.java:19270)
12-07 19:34:22.095: E/AndroidRuntime(13777): at android.os.Handler.handleCallback(Handler.java:733)
12-07 19:34:22.095: E/AndroidRuntime(13777): at android.os.Handler.dispatchMessage(Handler.java:95)
12-07 19:34:22.095: E/AndroidRuntime(13777): at android.os.Looper.loop(Looper.java:146)
12-07 19:34:22.095: E/AndroidRuntime(13777): at android.app.ActivityThread.main(ActivityThread.java:5602)
12-07 19:34:22.095: E/AndroidRuntime(13777): at java.lang.reflect.Method.invokeNative(Native Method)
12-07 19:34:22.095: E/AndroidRuntime(13777): at java.lang.reflect.Method.invoke(Method.java:515)
12-07 19:34:22.095: E/AndroidRuntime(13777): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
12-07 19:34:22.095: E/AndroidRuntime(13777): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
12-07 19:34:22.095: E/AndroidRuntime(13777): at dalvik.system.NativeStart.main(Native Method)
我认为问题是这个＆＃34;线程退出未捕获的异常＆＃34;部分，我不知道异常是什么或导致它的原因。
这是我的代码：
MainActivity.java： package com.example.parents_gps;
package com.example.parents_gps;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserFactory;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
private final String SERVER_ADDRESS = "http://210.119.84.108/Gps";
AsyncTask<Void, Integer, Void> myTask;
ArrayList<String> identity, password;
int dataSize = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button loginBtn, registerBtn;
final EditText id, pw;
loginBtn = (Button) findViewById(R.id.loginBtn);
registerBtn = (Button) findViewById(R.id.registerBtn);
id = (EditText) findViewById(R.id.id);
pw = (EditText) findViewById(R.id.pw);
loginBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (String.valueOf(id.getText()) == String.valueOf(identity.get(0))
&& String.valueOf(pw.getText()) == String.valueOf(password.get(0))) {
Toast.makeText(MainActivity.this, "로그인 완료", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(MainActivity.this, LoginSuccess.class);
startActivity(intent);
} else
Toast.makeText(MainActivity.this, "ID 혹은 P/W가 올바르지 않습니다.", Toast.LENGTH_SHORT).show();
myTask = new AsyncTask<Void, Integer, Void>() {
@Override
protected Void doInBackground(Void... params) {
try {
URL url = new URL(SERVER_ADDRESS + "/search_regpar.php");
url.openStream();
identity = getXmlDataList("searchresult_p.xml", "identity");
password = getXmlDataList("searchresult_p.xml", "password");
dataSize = identity.size();
Log.i("Test", String.valueOf(identity.get(0)));
Log.i("Test2", String.valueOf(id.getText()));
for (int i = 0; i < dataSize; i++)
Log.d("size", String.valueOf(identity.get(i)));
} catch (Exception e) {
Log.e("Error", e.getMessage());
}
return null;
}
private ArrayList<String> getXmlDataList(String filename, String str) {
String rss = SERVER_ADDRESS + "/";
ArrayList<String> ret = new ArrayList<String>();
try {
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(true);
XmlPullParser xpp = factory.newPullParser();
URL server = new URL(rss + filename);
InputStream is = server.openStream();
xpp.setInput(is, "UTF-8");
int eventType = xpp.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
if (eventType == XmlPullParser.START_TAG) {
if (xpp.getName().equals(str)) {
ret.add(xpp.nextText());
}
}
eventType = xpp.next();
}
} catch (Exception e) {
Log.e("Error", e.getMessage());
}
return ret;
}
};
myTask.execute();
}
});
registerBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, RegisterActivity.class);
startActivity(intent);
}
});
}
}
这是我的activity_main.xml和AndroidManifest.xml：
activity_main.xml中：
<LinearLayout 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:gravity="center"
android:orientation="vertical"
tools:context="com.example.parents_gps.MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="어서오세요"
android:textSize="20sp" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="ID"
android:textSize="20sp" />
<EditText
android:id="@+id/id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="xxx@mail.com"
android:textSize="20sp" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="P/W"
android:textSize="20sp" />
<EditText
android:id="@+id/pw"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="Password를 입력하세요"
android:textSize="20sp" />
</LinearLayout>
<Button
android:id="@+id/loginBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="로그인"
android:textSize="20sp" />
<Button
android:id="@+id/registerBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="회원가입"
android:textSize="20sp" />
</LinearLayout>
的AndroidManifest.xml：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.parents_gps"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="21" />
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".InfoTraced"
android:label="@string/app_name" >
</activity>
<activity
android:name=".InfoParents"
android:label="@string/app_name" >
</activity>
<activity
android:name=".InfoEdit"
android:label="@string/app_name" >
</activity>
<activity
android:name=".RegisterTraced"
android:label="@string/app_name" >
</activity>
<activity
android:name=".RegisterParents"
android:label="@string/app_name" >
</activity>
<activity
android:name=".LoginSuccess"
android:label="@string/app_name" >
</activity>
<activity
android:name=".MapView"
android:label="@string/app_name" >
</activity>
<activity
android:name=".RegisterActivity"
android:label="@string/app_name" >
</activity>
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyBJe2YzPGrINQM88R8yXpVisnC1sl1TpT8" />
</application>
</manifest>
答案 0 :(得分：0)
看起来你没有把你的'身份'和'密码'数组列表初始化。当你在这里比较它们时它们是空的：
if (String.valueOf(id.getText()) == String.valueOf(identity.get(0))
&& String.valueOf(pw.getText()) == String.valueOf(password.get(0))) {