Android活动错误

Question

我是android的新手.在android中我试图运行一个简单的工作.从我的main.xml(http://pastebin.com/Mhgmpj4w)我有一个按钮(我的main.java(http://pastebin.com/b5irLVTc))它将切换到另一个活动second.xml(http: //pastebin.com/F92VxSEZ)它会显示一些文本(我的second.java(http://pastebin.com/MR3L5WXL))但有一些错误(http://pastebin.com/KH2wDh7b).我是新手,请帮帮我.

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />

</LinearLayout>    

main.java:

    package com.rana.activities;

    import android.app.Activity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;

    public class Main extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

            Button b = (Button) findViewById(android.R.id.button1);
            b.setOnClickListener(new OnClickListener() {

                public void onClick(View v) {
                    startActivity(new Intent(Main.this, Second.class));
                }
            });
        }
    }

second.xml:

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="This is the second activity" />

    </LinearLayout>

second.java:

    package com.rana.activities;

    import android.app.Activity;
    import android.os.Bundle;

    public class Second extends Activity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            setContentView(R.layout.second);
        }

    }

logcat的:

    10-29 19:19:25.377: D/AndroidRuntime(859): Shutting down VM
    10-29 19:19:25.377: W/dalvikvm(859): threadid=1: thread exiting with uncaught exception (group=0x40015560)
    10-29 19:19:25.397: E/AndroidRuntime(859): FATAL EXCEPTION: main
    10-29 19:19:25.397: E/AndroidRuntime(859): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rana.activities/com.rana.activities.Main}: java.lang.NullPointerException
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.os.Handler.dispatchMessage(Handler.java:99)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.os.Looper.loop(Looper.java:123)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.ActivityThread.main(ActivityThread.java:3683)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at java.lang.reflect.Method.invokeNative(Native Method)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at java.lang.reflect.Method.invoke(Method.java:507)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at dalvik.system.NativeStart.main(Native Method)
    10-29 19:19:25.397: E/AndroidRuntime(859): Caused by: java.lang.NullPointerException
    10-29 19:19:25.397: E/AndroidRuntime(859):  at com.rana.activities.Main.onCreate(Main.java:18)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    10-29 19:19:25.397: E/AndroidRuntime(859):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
    10-29 19:19:25.397: E/AndroidRuntime(859):  ... 11 more
    <-------LogCat------------------->

Answer 1

将其替换android.R.id.button1为R.id.button1并导入您自己的包R类main.java.它将解决问题.通过这种方式,它将从您的应用程序中分配内存,因此它不会搜索全局资源