Java 使用自定义视图时出现NullPointerException
您好,我创建了一个扩展relativeLayout的自定义视图。我想让它可以定制Java 使用自定义视图时出现NullPointerException,java,android,view,nullpointerexception,null-pointer,Java,Android,View,Nullpointerexception,Null Pointer,您好,我创建了一个扩展relativeLayout的自定义视图。我想让它可以定制 public class Niveauview extends RelativeLayout { public TextView musiqueView = new TextView(getContext()), artisteView = new TextView(getContext()); public ImageView coverView = new ImageView(getContext()), c
public class Niveauview extends RelativeLayout {
public TextView musiqueView = new TextView(getContext()), artisteView = new TextView(getContext());
public ImageView coverView = new ImageView(getContext()), carapaceView = new ImageView(getContext());
public Niveauview(Context context){
super(context);
}
public void init(int cover, int musique,int artiste){
coverView = (ImageView)findViewById(R.id.cover);
coverView.setImageResource(cover);
musiqueView = (TextView)findViewById(R.id.musique);
musiqueView.setText(musique);
artisteView = (TextView)findViewById(R.id.artiste);
artisteView.setText(artiste);
carapaceView = (ImageView) findViewById(R.id.carapace);
carapaceView.setImageResource(R.drawable.carapacevide);
}}
这是我的主要活动
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initNiveauView();
}
private void initNiveauView(){
Niveauview luv_grow_view = new Niveauview(getApplicationContext());
luv_grow_view = (Niveauview)findViewById(R.id.luv_growup_view);
luv_grow_view.init(R.drawable.luv_groweup,R.string.GrowUp,R.string.LilUziVert);
}}
和我的xml文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
tools:context="fr.freshkamekentrainement.skrt.MainActivity">
<ImageView
android:contentDescription="@string/header_content_description"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="@drawable/header"
android:id="@+id/header"
android:scaleType="fitStart"
/>
<fr.freshkamekentrainement.skrt.view.NiveauView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/luv_growup_view"/>
可能您没有修改其他显示分辨率的布局。
重新生成应用程序并验证此操作。这是因为您尚未设置此操作
setContentView(R.layout.YourXMLfile name);
在调用initNiveauView()方法之前,首先
Niveauview luv_grow_view=newniveauview(getApplicationContext())代码>然后在下一行luv_grow_view=(Niveauview)findViewById(R.id.luv_grow_view)代码>看起来您在实现中犯了很多错误,本教程介绍了如何创建非常好的复合视图:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void fr.freshkamekentrainement.skrt.view.Niveauview.init(int, int, int)' on a null object reference
at fr.freshkamekentrainement.skrt.MainActivity.initNiveauView(MainActivity.java:24)
at fr.freshkamekentrainement.skrt.MainActivity.onCreate(MainActivity.java:17)
setContentView(R.layout.YourXMLfile name);