無法開始新的活動

Question

{我知道已經有像這樣的問題一大堆，但我不能看到有關我的程序的任何問題。}

我有一個Android應用程序時開始活動ComponentInfo這應該從EditText獲取一個名稱並將其放入另一個活動的TextView中。它以前工作過，但是如果EditText的值等於「ANDROID」，我希望它啓動另一個活動。然而，現在當我嘗試開始任何活動時，該應用程序崩潰。

第一活動：

package net.timtim17.dev.android.fun.nametag; 

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

public class MainActivity extends Activity { 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    final EditText et = (EditText) findViewById(R.id.editText1); 
    Button submit = (Button) findViewById(R.id.button1); 
    submit.setOnClickListener(new OnClickListener(){ 

     @Override 
     public void onClick(View v) { 
      String text = et.getText().toString(); 
      if(text.equals("ANDROID")){ 
       Intent android = new Intent(MainActivity.this, AndroidNameTag.class); 
       startActivity(android); 
      }else{ 
       Intent intent = new Intent(MainActivity.this, NameTag.class); 
       intent.putExtra("name", text); 
       startActivity(intent); 
      } 

     } 

    }); 
} 

} 

名籤的活動：

package net.timtim17.dev.android.fun.nametag; 

import android.app.Activity; 

import android.os.Bundle; 

import android.widget.TextView; 

public class NameTag extends Activity { 

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

    TextView tv = (TextView) findViewById(R.id.textView2); 
    tv.setText(getIntent().getExtras().getString("name")); 
} 
} 

AndroidNameTag活動：

package net.timtim17.dev.android.fun.nametag; 

import android.app.Activity; 

import android.graphics.drawable.AnimationDrawable; 

import android.os.Bundle; 
import android.widget.ImageView; 

public class AndroidNameTag extends Activity { 

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

    ImageView iv = (ImageView) findViewById(R.id.imageView1); 
    iv.setBackgroundResource(R.anim.animation); 
    AnimationDrawable anim = (AnimationDrawable) iv.getBackground(); 
    anim.start(); 
} 
} 

logcat的錯誤：

10-26 11:26:35.602: E/AndroidRuntime(2900): FATAL EXCEPTION: main 
10-26 11:26:35.602: E/AndroidRuntime(2900): java.lang.RuntimeException: Unable to start activity ComponentInfo{net.timtim17.dev.android.fun.nametag/net.timtim17.dev.android.fun.nametag.NameTag}: java.lang.NullPointerException 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.ActivityThread.access$600(ActivityThread.java:141) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.os.Handler.dispatchMessage(Handler.java:99) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.os.Looper.loop(Looper.java:137) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.ActivityThread.main(ActivityThread.java:5103) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at java.lang.reflect.Method.invokeNative(Native Method) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at java.lang.reflect.Method.invoke(Method.java:525) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at dalvik.system.NativeStart.main(Native Method) 
10-26 11:26:35.602: E/AndroidRuntime(2900): Caused by: java.lang.NullPointerException 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at net.timtim17.dev.android.fun.nametag.NameTag.onCreate(NameTag.java:15) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.Activity.performCreate(Activity.java:5133) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175) 
10-26 11:26:35.602: E/AndroidRuntime(2900):  ... 11 more 

MainActivity佈局：

<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=".MainActivity" > 

<TextView 
    android:id="@+id/textView1" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentTop="true" 
    android:layout_marginTop="16dp" 
    android:text="@string/main_text" 
    android:textAppearance="?android:attr/textAppearanceMedium" /> 

<Button 
    android:id="@+id/button1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignRight="@+id/textView1" 
    android:layout_below="@+id/textView1" 
    android:layout_marginTop="14dp" 
    android:text="@string/submit_button" /> 

<EditText 
    android:id="@+id/editText1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignLeft="@+id/textView1" 
    android:layout_alignTop="@+id/button1" 
    android:ems="10" 
    android:inputType="textPersonName" > 

    <requestFocus /> 
</EditText> 

Answer 1

原來，我無意中打開了名籤活動和AndroidNameTag活動的佈局，並刪除在錯誤的活動第二的TextView ...