Android 单击按钮时不执行任何操作
我有Android 单击按钮时不执行任何操作,android,android-viewpager,onclicklistener,android-button,Android,Android Viewpager,Onclicklistener,Android Button,我有customView课程。此类是viewPager视图之一。我想在一个位置执行与控制ViewPager相关的所有逻辑:PagerAdapter,而不是在多个位置。我尝试过这样做,但当我单击按钮时-没有任何操作。 CustomView类: public class CustomView extends LinearLayout { private LayoutInflater mInflater; private Button button; private OnCli
customView
课程。此类是viewPager
视图之一。我想在一个位置执行与控制ViewPager
相关的所有逻辑:PagerAdapter
,而不是在多个位置。我尝试过这样做,但当我单击按钮时-没有任何操作。
CustomView类:
public class CustomView extends LinearLayout {
private LayoutInflater mInflater;
private Button button;
private OnClickListener clickListener;
public CustomView(@NonNull Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
mInflater = LayoutInflater.from(context);
View v = mInflater.inflate(R.layout.custom_view, this, true);
button = v.findViewById(R.id.button);
public void setClickListener(OnClickListener clickListener) {
this.clickListener = clickListener;
button.setOnClickListener(clickListener);
}
适配器类:
public class CustomPagerAdapter extends PagerAdapter {
private Context context;
private View.OnClickListener clickListener;
private CustomView customView;
public CustomPagerAdapter(Context context) {
this.context = context;
customView = new CustomView(context);
clickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d("debug", "works");
}
};
}
public void setCustomView(CustomView customView) {
this.customView = customView;
customView.setClickListener(clickListener);
}
.........
活动:
public class Activity extends AppCompatActivity {
private ViewPager viewPager;
private CustomPagerAdapter customPagerAdapter;
private CustomView customView;
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
customView = new CustomView(this);
customPagerAdapter = new CustomPagerAdapter(this);
viewPager = findViewById(R.id.viewPager);
viewPager.setAdapter(customPagerAdapter);
customPagerAdapter.setCustomView(customView);
}
}
将此方法从自定义视图构造函数移到外部,并在创建视图后调用它:
public void setClickListener(OnClickListener clickListener) {
this.clickListener = clickListener;
button.setOnClickListener(clickListener);
}
将此方法从自定义视图构造函数移到外部,并在创建视图后调用它:
public void setClickListener(OnClickListener clickListener) {
this.clickListener = clickListener;
button.setOnClickListener(clickListener);
}
在这种情况下,我会得到异常:
NullPointerException:尝试在空对象引用上调用虚拟方法“void android.widget.Button.setOnClickListener(android.view.view$OnClickListener)”
@Monica尝试仅在适配器中创建CustomView,然后使用日志创建侦听器,然后调用setClickListener。别忘了检查Null按钮如果我只在adapter中创建CustomView
并从Activity
中删除CustomView
,我会得到异常:java.lang.NullPointerException:尝试调用虚拟方法'void com.company.example.CustomView.SetonnextButtonClicklListener(android.view.view$OnClickListener)'在空对象引用上
linecustomView.setOnNextButtonClickListener(onNextButtonClickListener)
在这种情况下,我得到异常:NullPointerException:尝试在空对象引用上调用虚拟方法“void android.widget.Button.setOnClickListener(android.view.view$OnClickListener)”
@Monica尝试仅在适配器中创建CustomView,然后使用日志创建侦听器,然后调用setClickListener。别忘了检查Null按钮如果我只在adapter中创建CustomView
并从Activity
中删除CustomView
,我会得到异常:java.lang.NullPointerException:尝试调用虚拟方法'void com.company.example.CustomView.SetonnextButtonClicklListener(android.view.view$OnClickListener)'在空对象引用上
linecustomView.setOnNextButtonClickListener(onNextButtonClickListener)代码>使用完整的CustomPagerAdapter更新问题。使用完整的CustomPagerAdapter更新问题。