Java 尝试调用虚拟方法';android.view.ViewGroup$LayoutParams android.view.view.getLayoutParams()';关于空对象引用
我正在制作一个简单的Android列表视图应用程序,它将在列表视图中显示一些基本名称。我的应用程序意外停止。logcat正在显示此错误Java 尝试调用虚拟方法';android.view.ViewGroup$LayoutParams android.view.view.getLayoutParams()';关于空对象引用,java,android,listview,Java,Android,Listview,我正在制作一个简单的Android列表视图应用程序,它将在列表视图中显示一些基本名称。我的应用程序意外停止。logcat正在显示此错误 Attempt to invoke virtual method 'android.view.ViewGroup$LayoutParams android.view.View.getLayoutParams()' on a null object reference. 自定义适配器 public class CustomAdapter extends
Attempt to invoke virtual method 'android.view.ViewGroup$LayoutParams android.view.View.getLayoutParams()'
on a null object reference.
自定义适配器
public class CustomAdapter extends BaseAdapter {
Context context;
String animals[];
LayoutInflater inflater;
public CustomAdapter(Context applicationContext, String[] animals){
this.context = applicationContext;
this.animals = animals;
inflater = (LayoutInflater.from(applicationContext));
}
@Override
public int getCount() {
return animals.length;
}
@Override
public Object getItem(int i) {
return null;
}
@Override
public long getItemId(int i) {
return 0;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
view = inflater.inflate(R.layout.listview, null);
TextView textView = (TextView) view.findViewById(R.id.tv);
textView.setText(animals[i]);
return null;
}
}
主要活动
public class MainActivity extends AppCompatActivity {
ListView listView;
String animals[]= {"Dog", "Cat", "Humans", "Monkey", "Rat", "Snake", "Elephant", "Giraffe", "Deer", "Tiger", "Lion","Cow", "Pig", "Goat"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView =(ListView) findViewById(R.id.lv);
CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), animals);
listView.setAdapter(customAdapter);
}
}
你犯了错误
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
view = inflater.inflate(R.layout.listview, null);
TextView textView = (TextView) view.findViewById(R.id.tv);
textView.setText(animals[i]);
return view;
}
及
短片
这是你在哪一行买的?基本上,这是一个nullpointerexception。你知道那是什么吗?你的两个硬编码方法返回null有什么特别的原因吗?我只是遵循了一个tuitorial。很可能这是一个糟糕的方法,或者你没有完全遵循它,或者没有足够的遵循它。我犯了我的错误。是的,我明白了。谢谢你。
public long getItemId(int i) {
return animals.length;
}