Question

hi sir I got this error when my app was launched. When I run my project unfortunately project was stop. This error is coming my log cat. When click on app unfortunately app was stop msg came.

我在activity_xml上放了一个文本视图。点击导航到另一个页面但这里不显示我的第一页。 mainactivity.java和activity main.xml存在问题错误是java.lang.runtime异常：无法启动活动组件Info {com.example.b / com.example.b.MainActivity}：java。 Lang.NullPointerException

**mainactivity.java**
andheri = (TextView) findViewById(R.id.Andheri1);
        andheri.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                Context context = null;
                // TODO Auto-generated method stub
                Intent intent = new Intent(context,andheri.class);
                startActivity(intent);   

            }

        });
**activity_xml**
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="match_parent" >

<RelativeLayout 
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:background="@drawable/untitled1"
    >



    <TextView
        android:id="@+id/Andher1"
        android:layout_width="80dp"
        android:layout_height="20dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:background="#FFE4B5"
        android:capitalize="characters"
        android:gravity="center"
        android:text="Andheri"
        android:textColor="#000000"
        android:textColorHint="#0000CD"
        android:textSize="15dp"
        android:textStyle="bold" />
</RelativeLayout>
</ScrollView>

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

        </activity>
    </application>

Answer 1

你应该改变这个

andheri = (TextView) findViewById(R.id.Andheri1);

到

andheri = (TextView) findViewById(R.id.Andher1);

您的TextView ID为id/Andher1，并且您尝试将其设为@+id/Andheri1。所以你得到NPE。

Answer 2

在您从主活动发送的意图中，您应该将上下文设置为此，而不是空

并更改textview的ID，您错过了'i'

java lang运行时异常：无法启动活动组件信息

2 个答案: