Question

这是我的MainActivity.java代码在这里，我正在创建一个非常基本的LoginApp。当应用程序运行时，它“不幸地停止了工作错误......”

package com.example.loginapp;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
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 implements OnClickListener {
EditText t1,t2;
Button b1;

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

    b1= (Button) b1.findViewById(R.id.button1);
    t1=(EditText) t1.findViewById(R.id.editText1);
    t2=(EditText) t2.findViewById(R.id.editText2);

}

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

@Override
public void onClick(View arg0) 
{
    //String user;      
    //user = t1.setText("user");

    if (arg0.findViewById(R.id.button1)==b1)
    {

    if ((boolean)((t1.getText().toString()=="user")) && (t2.getText().toString()=="user"))

    {
        Toast.makeText(this, "Login Sucessful", Toast.LENGTH_SHORT).show();

    }   
    else
    {
        Toast.makeText(this, "Sorry", Toast.LENGTH_SHORT).show();   
        t1.setText("");
        t2.setText("");

    }
    }
}
}

以下是activity_main.xml的代码

<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:gravity="center"
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=".MainActivity" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignTop="@+id/editText1"
    android:text="Username"        
    android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView1"
    android:layout_centerVertical="true"
    android:text="Password"
    android:textAppearance="?android:attr/textAppearanceLarge" />



<EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="115dp"
    android:layout_marginTop="22dp"
    android:ems="10" >


</EditText>

 <EditText
    android:id="@+id/editText2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/textView2"
    android:layout_alignLeft="@+id/editText1"
    android:ems="10"
    android:inputType="numberPassword" />

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/textView2"
    android:layout_marginTop="46dp"
    android:layout_toRightOf="@+id/textView2"
    android:clickable="true"
    android:onClick="onClick"
    android:text="Login" />

</RelativeLayout>

AndroidManifest.xml的代码

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.loginapp"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="14"
    android:targetSdkVersion="18" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.example.loginapp.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>
</application>

</manifest>

Answer 1

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

     b1= (Button) findViewById(R.id.button1);
     t1=(EditText) findViewById(R.id.editText1);
     t2=(EditText) findViewById(R.id.editText2);
}

这对你有帮助。修改完代码后，它对我来说很好。请尝试让我知道。

应用程序不幸停止工作

1 个答案: