Question

我正在开发一个开发登录屏幕的应用程序。

我无法运行该应用。

我的xml文件：

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".Login" 
    android:background="@drawable/msngr">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="24dp"
        android:text="LoginID"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/etName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_alignRight="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="20dp"
        android:ems="10"
        android:background="@android:drawable/editbox_background"
        android:inputType="textPersonName" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/etName"
        android:layout_below="@+id/etName"
        android:layout_marginTop="41dp"
        android:text="Password"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <EditText
        android:id="@+id/etPassword"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView2"
        android:layout_centerVertical="true"
        android:ems="10"
        android:background="@android:drawable/editbox_background"
        android:inputType="textPassword" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/btnLogin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/etPassword"
        android:layout_below="@+id/etPassword"
        android:layout_marginTop="33dp"
        android:text=""
         android:background="@drawable/login" />

</RelativeLayout>

的.java：

package com.example.message_reader_dcall;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Login extends Activity  
{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        final EditText etName=(EditText)findViewById(R.id.etName);
        final EditText etPassword=(EditText)findViewById(R.id.etPassword);

        final Button btnLogin =(Button)findViewById(R.id.btnLogin);

        final gaRemoteConnection objConnect=new gaRemoteConnection();

        btnLogin.setOnClickListener(new OnClickListener() 
        {

            public void onClick(View v) {
                // TODO Auto-generated method stub

                objConnect.setConnection("AndroidDB", "sa", "ok");

                if(objConnect.checkUser(etName.getText().toString(),etPassword.getText().toString()))
                {
                    //Intent i= new Intent(getApplicationContext(),Messages.class);
                    //startActivity(i);
                }


            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.login, menu);
        return true;
    }

}

logcat的：

09-10 17:22:39.968: E/AndroidRuntime(1472): FATAL EXCEPTION: main
09-10 17:22:39.968: E/AndroidRuntime(1472): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.message_reader_dcall/com.example.message_reader_dcall.MainActivity}: java.lang.ClassNotFoundException: com.example.message_reader_dcall.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.message_reader_dcall-1.apk]
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.os.Looper.loop(Looper.java:123)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.ActivityThread.main(ActivityThread.java:3683)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at java.lang.reflect.Method.invokeNative(Native Method)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at java.lang.reflect.Method.invoke(Method.java:507)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at dalvik.system.NativeStart.main(Native Method)
09-10 17:22:39.968: E/AndroidRuntime(1472): Caused by: java.lang.ClassNotFoundException: com.example.message_reader_dcall.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.example.message_reader_dcall-1.apk]
09-10 17:22:39.968: E/AndroidRuntime(1472):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
09-10 17:22:39.968: E/AndroidRuntime(1472):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)

Answer 1

尽管您的代码显示MainActivity Login，但您仍尝试启动Activity。

确保您在Activity中使用与代码中相同的AndroidManifest.xml名称还要确保您的IDE想要启动正确的Activty。

Answer 2

根据您的日志

尝试此操作

更改

public class Login extends Activity  
{
}

到

public class MainActivity extends Activity  
{}

无法启动我的应用

2 个答案: