Question

MyApp包含1个TextView和2个按钮 - 添加和子。按下添加按钮时，计数器++。 sub - ＆gt;反击 - 。

我从控制台获得了msg - 无法获得wglGetExtensionsStringARB。

可以看到主页。无法打开MyApp。需要强制关闭。

主：

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context="com.btp.myapp.MainActivity">

<item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:title="@string/action_settings"
    />

</menu>

清单：

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

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="19" />

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

MainActivity.java：

package com.btp.myapp;
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;


  public class MainActivity extends ActionBarActivity {


int counter;
Button add, sub;
TextView display;


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

    counter = 0;
    add = (Button) findViewById(R.id.add);
    sub = (Button) findViewById(R.id.sub);
    display = (TextView)findViewById(R.id.textView2);
    add.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            // TODO Auto-generated method stub
            counter++;
            display.setText("Your total is" + counter);

        }
    });

    sub.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            // TODO Auto-generated method stub
            counter--;
            display.setText("Your total is" + counter);
        }
    });


    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }
}

@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 boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {

    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container,
                false);
        return rootView;
    }
}

}

logcat的：

06-18 04:05:45.942: I/dalvikvm(325): Could not find method
android.content.pm.PackageManager.getActivityLogo, referenced from method
android.support.v7.internal.widget.ActionBarView.<init>
06-18 04:05:45.942: W/dalvikvm(325): VFY: unable to resolve virtual method 318: Landroid/content/pm/PackageManager;.getActivityLogo (Landroid/content/ComponentName;)Landroid/graphics/drawable/Drawable;
06-18 04:05:45.942: D/dalvikvm(325): VFY: replacing opcode 0x6e at 0x008b
06-18 04:05:45.951: I/dalvikvm(325): Could not find method android.content.pm.ApplicationInfo.loadLogo, referenced from method android.support.v7.internal.widget.ActionBarView.<init>
06-18 04:05:45.951: W/dalvikvm(325): VFY: unable to resolve virtual method 314: Landroid/content/pm/ApplicationInfo;.loadLogo (Landroid/content/pm/PackageManager;)Landroid/graphics/drawable/Drawable;
06-18 04:05:45.951: D/dalvikvm(325): VFY: replacing opcode 0x6e at 0x0099
06-18 04:05:45.972: D/dalvikvm(325): VFY: dead code 0x008e-0092 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
06-18 04:05:45.972: D/dalvikvm(325): VFY: dead code 0x009c-00a0 in Landroid/support/v7/internal/widget/ActionBarView;.<init> (Landroid/content/Context;Landroid/util/AttributeSet;)V
06-18 04:05:46.221: D/AndroidRuntime(325): Shutting down VM
06-18 04:05:46.221: W/dalvikvm(325): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
06-18 04:05:46.241: E/AndroidRuntime(325): FATAL EXCEPTION: main
06-18 04:05:46.241: E/AndroidRuntime(325): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.btp.myapp/com.btp.myapp.MainActivity}: java.lang.NullPointerException
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
06-18 04:05:46.241: E/AndroidRuntime(325):  at  android.os.Handler.dispatchMessage(Handler.java:99)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.os.Looper.loop(Looper.java:123)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.ActivityThread.main(ActivityThread.java:4627)
06-18 04:05:46.241: E/AndroidRuntime(325):  at java.lang.reflect.Method.invokeNative(Native Method)
06-18 04:05:46.241: E/AndroidRuntime(325):  at java.lang.reflect.Method.invoke(Method.java:521)
06-18 04:05:46.241: E/AndroidRuntime(325):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
06-18 04:05:46.241: E/AndroidRuntime(325):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
06-18 04:05:46.241: E/AndroidRuntime(325):  at dalvik.system.NativeStart.main(Native Method)
06-18 04:05:46.241: E/AndroidRuntime(325): Caused by: java.lang.NullPointerException
06-18 04:05:46.241: E/AndroidRuntime(325):  at com.btp.myapp.MainActivity.onCreate(MainActivity.java:32)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
06-18 04:05:46.241: E/AndroidRuntime(325):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
06-18 04:05:46.241: E/AndroidRuntime(325):  ... 11 more

Answer 1

日志引用MainActivity中第32行抛出的空引用异常。

这就是这条线 add.setOnClickListener（new View.OnClickListener（）{

现在从该行加载了对象'add' add =（Button）findViewById（R.id.add）;

查看你的xml文件，我看不到你有一个id为'add'的资源，这可能解释了它。因此无法找到您的资源，因此'add'为空

Android - 强制关闭应用程序

1 个答案: