java无法实例化activity ComponentInfo以启动我的应用程序
我在启动应用程序时遇到此错误,如何解决此问题
12112-12112/com.javacodegeeks.安卓qrcodeexample E/AndroidRuntime﹕ FATAL EXCEPTION: main java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.javacodegeeks.安卓qrcodeexample/com.javacodegeeks.安卓qrcodeexample.Login}: java.lang.NullPointerException
这是我的。xml文件:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
package="com.javacodegeeks.安卓qrcodeexample"
安卓:versionCode="1"
安卓:versionName="1.0" >
<uses-sdk
安卓:minSdkVersion="8"
安卓:targetSdkVersion="19" />
<application
安卓:allowBackup="true"
安卓:icon="@drawable/ic_launcher"
安卓:label="@string/app_name" >
<activity
安卓:name="com.javacodegeeks.安卓qrcodeexample.AndroidBarcodeQrExample"
安卓:label="@string/app_name" >
</activity>
<activity
安卓:name="com.javacodegeeks.安卓qrcodeexample.Login"
安卓:label="@string/app_name" >
<intent-filter>
<action 安卓:name="安卓.intent.action.MAIN" />
<category 安卓:name="安卓.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
这里是我的活动:
package com.javacodegeeks.安卓qrcodeexample;
/**
* Created by Andre on 14/06/15.
*/
import 安卓.app.Activity;
import 安卓.app.AlertDialog;
import 安卓.content.ActivityNotFoundException;
import 安卓.content.DialogInterface;
import 安卓.content.Intent;
import 安卓.net.Uri;
import 安卓.os.Bundle;
import 安卓.view.View;
import 安卓.widget.EditText;
import 安卓.widget.Toast;
public class Login extends Activity {
EditText username = (EditText)findViewById(R.id.editText);
EditText password = (EditText)findViewById(R.id.editText2);
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
}
public void login(View view) {
if (username.getText().toString().equals("admin") && password.getText().toString().equals("admin")) {
Toast toast = Toast.makeText(this, "CORRECT PW", Toast.LENGTH_LONG);
toast.show();
//correcct password
Intent i = new Intent(getApplicationContext(), AndroidBarcodeQrExample.class);
i.putExtra("Disco", username.getText().toString());
startActivity(i);
} else {
Toast toast = Toast.makeText(this, "UNCORRECT PW", Toast.LENGTH_LONG);
toast.show();
//wrong password
}
}
}
# 1 楼答案
移动行:
内部
onCreate