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[英]Android Library project in Eclipse: RunTimeException ClassNotFoundException
[英]Android RuntimeException Eclipse
大家好,我想做單位轉換器,但是當我運行它時,它會停下來向我展示
05-15 15:30:45.237:D / AndroidRuntime(333):關閉VM 05-15 15:30:45.237:W / dalvikvm(333):threadid = 1:線程退出且未捕獲異常(group = 0x40015560)05 -15 15:30:45.288:E / AndroidRuntime(333):致命異常:主05-15 15:30:45.288:E / AndroidRuntime(333):java.lang.RuntimeException:無法實例化活動ComponentInfo {org.alaenvargut .conversor / org.alaenvargut.conversor.MainActivity}:java.lang.NullPointerException 05-15 15:30:45.288:E / AndroidRuntime(333):位於android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)05- 15 15:30:45.288:E / AndroidRuntime(333):位於android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)05-15 15:30:45.288:E / AndroidRuntime(333):位於android.app。 ActivityThread.access $ 1500(ActivityThread.java:117)05-15 15:30:45.288:E / AndroidRuntime(333):at android.app.ActivityThread $ H.handleMessage(ActivityThread.java:931)05-15 15:30 :45.288:E / AndroidRuntime(333):位於android.os.Handler.dispatchMessage(Handler。 java:99)05-15 15:30:45.288:E / AndroidRuntime(333):位於android.os.Looper.loop(Looper.java:123)05-15 15:30:45.288:E / AndroidRuntime(333) :在android.app.ActivityThread.main(ActivityThread.java:3683)05-15 15:30:45.288:E / AndroidRuntime(333):在java.lang.reflect.Method.invokeNative(本機方法)05-15 15 :30:45.288:E / AndroidRuntime(333):在java.lang.reflect.Method.invoke(Method.java:507)05-15 15:30:45.288:E / AndroidRuntime(333):在com.android。 internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:839)05-15 15:30:45.288:E / AndroidRuntime(333):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597 )05-15 15:30:45.288:E / AndroidRuntime(333):在dalvik.system.NativeStart.main(本機方法)05-15 15:30:45.288:E / AndroidRuntime(333):原因:java。 lang.NullPointerException 05-15 15:30:45.288:E / AndroidRuntime(333):在android.app.Activity.findViewById(Activity.java:1647)05-15 15:30:45.288:E / AndroidRuntime(333):在org.alaenvargut.conversor.MainActivity((MainActivit y.java:13)05-15 15:30:45.288:E / AndroidRuntime(333):at java.lang.Class.newInstanceImpl(Native Method)05-15 15:30:45.288:E / AndroidRuntime(333):在java.lang.Class.newInstance(Class.java:1409)05-15 15:30:45.288:E / AndroidRuntime(333):在android.app.Instrumentation.newActivity(Instrumentation.java:1021)05-15 15 :30:45.288:E / AndroidRuntime(333):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)05-15 15:30:45.288:E / AndroidRuntime(333):...還有11個
這是我的主要代碼
package org.alaenvargut.conversor;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Spinner;
import android.widget.ArrayAdapter;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
public class MainActivity extends Activity implements OnItemSelectedListener{
public Spinner SUni = (Spinner) findViewById(R.id.spinner1);
public Spinner SFm = (Spinner) findViewById(R.id.spinner2);
public Spinner STo = (Spinner) findViewById(R.id.spinner3);
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayAdapter AUni = ArrayAdapter.createFromResource(this, R.array.Unidades, android.R.layout.simple_selectable_list_item);
AUni.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
SUni.setAdapter(AUni);
SUni.setOnItemSelectedListener(this);
}
public void onItemSelected(AdapterView<?> parent, View view,int pos, long id)
{
if (parent.getId() == R.id.spinner1)
{
switch((int)id)
{
case(1):
{
}
case(2):
{
ArrayAdapter AFm = ArrayAdapter.createFromResource(this, R.array.Velocidad, android.R.layout.simple_selectable_list_item);
AFm.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
SFm.setAdapter(AFm);
}
default:
}
}
}
public void onNothingSelected(AdapterView<?> parent)
{
// Another interface callback
}
}
這是我的布局
<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="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="19dp"
android:text="@string/principal" />
<Spinner
android:id="@+id/spinner1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/textView1"
android:layout_marginTop="15dp" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/spinner1"
android:layout_below="@+id/spinner1"
android:layout_marginTop="18dp"
android:text="@string/fm"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Spinner
android:id="@+id/spinner2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView2"
android:layout_centerHorizontal="true" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/spinner2"
android:layout_below="@+id/spinner2"
android:text="@string/to"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Spinner
android:id="@+id/spinner3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView3"
android:layout_centerHorizontal="true" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/spinner3"
android:layout_below="@+id/spinner3"
android:layout_marginTop="30dp"
android:text="@string/con" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/button1"
android:layout_alignRight="@+id/spinner3"
android:layout_marginRight="29dp"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
這是我從值的xml文件
> <?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="Unidades">
<item >Volumen</item>
<item >Velocidad</item>
</string-array>
<string-array name="Velocidad">
<item >Km/h</item>
<item >M/h</item>
</string-array>
</resources>
對異常有任何想法嗎?
您只需要在onCreate()方法中設置布局之后,然后在此之前初始化Spinners
。 只需嘗試如下:
public Spinner SUni;
public Spinner SFm;
public Spinner STo;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SUni = (Spinner) findViewById(R.id.spinner1);
SFm = (Spinner) findViewById(R.id.spinner2);
STo = (Spinner) findViewById(R.id.spinner3);
}
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