Android - 找不到方法 onButtonClick(View)
Android - Could not find method onButtonClick(View)
我的按钮 ID 有问题 "btn_scansiona" 一旦我点击它就会触发以下回溯：
java.lang.IllegalStateException: Could not find method onButtonClick(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'btn_scansiona'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:325)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
fragment_scan.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.test.myapp.ScanFragment">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="keywords"
android:id="@+id/textView3"
android:layout_gravity="center_horizontal|top"
android:textStyle="bold"
android:layout_marginTop="40dp"
android:textSize="20dp" />
<Button
android:layout_width="200dp"
android:layout_height="wrap_content"
android:text="scansiona"
android:id="@+id/btn_scansiona"
android:layout_gravity="center_horizontal|bottom"
android:textStyle="bold"
android:layout_marginBottom="40dp"
android:background="#ffaa00"
android:onClick="onButtonClick" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Insert keywords"
android:id="@+id/textSearch"
android:layout_marginTop="80dp"
android:layout_gravity="center_horizontal|top"
android:enabled="true"
android:inputType="text"
android:textColor="@color/abc_input_method_navigation_guard"
android:textIsSelectable="false"
android:textSize="20sp"
android:textStyle="bold"
android:selectAllOnFocus="false" />
ScanFragment.java
public class ScanFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public ScanFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment ScanFragment.
*/
// TODO: Rename and change types and number of parameters
public static ScanFragment newInstance(String param1, String param2) {
ScanFragment fragment = new ScanFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_scan, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
mListener = (OnFragmentInteractionListener) context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
//DB
private DbManager db=null;
private CursorAdapter adapter;
String date = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
public void onButtonClick(View view){
//do something when button is clicked.
EditText txt=(EditText) view.findViewById(R.id.textSearch);
if (txt.length()>0 && date.length()>0)
{
db.save(txt.getEditableText().toString(), date);
adapter.changeCursor(db.query());
}
}
}
如果我在 MainActivity.java 上声明方法 "onButtonClick"，则以下回溯消失，但我收到另一个关于 "txt.length" 不能为空的回溯。
我的错误在哪里？谢谢
丹妮尔
将您的方法 'onButtonClick' 移动到您的 activity。
首先，onClick 方法应该出现在父 activity 中，这就是为什么在将代码移至 activity 时不会出现错误的原因class
或
如果你想把它放在你的片段中，那么你必须在片段中初始化按钮并为其设置 onClickListener，像这样：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout. fragment_scan,
container, false);
Button button = (Button) view.findViewById(R.id.btn_scansiona);
button.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
// do something
}
});
return view;
}
你得到 txt.length() can't be null error because :
- 您已将
txt 定义为您的 EditText 而不是其中的文字。您必须像这样获取 text 并将其转换为 String ：
txt.getText().toString()
然后你可以像这样进行正常处理:
txt.getText().toString().length()
而不是在布局中定义 ButtonClickListener 方法。你为什么不在代码中定义 buttonClickListener..
从布局和代码中删除 android:onClick 标签.. 使用
Button btnScan = view.findViewById(R.id.btn_scansiona
btnScan.onClickListener(.....){
//your rest code here....
}
欢迎丹妮尔
您必须在 activity 中定义该方法。
顺便说一句，如果您想以这种方式编写代码，我建议您使用 Butterknife 库。非常简单：
public class FancyFragment extends Fragment {
@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fancy_fragment, container, false);
ButterKnife.bind(this, view);
return view;
}
@OnClick(R.id.submit) public void submit(View view) {
// do something ... }
}
}
build.gradle
compile 'com.jakewharton:butterknife:8.1.0'
apt 'com.jakewharton:butterknife-compile
我的按钮 ID 有问题 "btn_scansiona" 一旦我点击它就会触发以下回溯：
java.lang.IllegalStateException: Could not find method onButtonClick(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'btn_scansiona'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:325)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:4780)
at android.view.View$PerformClick.run(View.java:19866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
fragment_scan.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.test.myapp.ScanFragment">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="keywords"
android:id="@+id/textView3"
android:layout_gravity="center_horizontal|top"
android:textStyle="bold"
android:layout_marginTop="40dp"
android:textSize="20dp" />
<Button
android:layout_width="200dp"
android:layout_height="wrap_content"
android:text="scansiona"
android:id="@+id/btn_scansiona"
android:layout_gravity="center_horizontal|bottom"
android:textStyle="bold"
android:layout_marginBottom="40dp"
android:background="#ffaa00"
android:onClick="onButtonClick" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Insert keywords"
android:id="@+id/textSearch"
android:layout_marginTop="80dp"
android:layout_gravity="center_horizontal|top"
android:enabled="true"
android:inputType="text"
android:textColor="@color/abc_input_method_navigation_guard"
android:textIsSelectable="false"
android:textSize="20sp"
android:textStyle="bold"
android:selectAllOnFocus="false" />
ScanFragment.java
public class ScanFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public ScanFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment ScanFragment.
*/
// TODO: Rename and change types and number of parameters
public static ScanFragment newInstance(String param1, String param2) {
ScanFragment fragment = new ScanFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_scan, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
mListener = (OnFragmentInteractionListener) context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
//DB
private DbManager db=null;
private CursorAdapter adapter;
String date = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
public void onButtonClick(View view){
//do something when button is clicked.
EditText txt=(EditText) view.findViewById(R.id.textSearch);
if (txt.length()>0 && date.length()>0)
{
db.save(txt.getEditableText().toString(), date);
adapter.changeCursor(db.query());
}
}
}
如果我在 MainActivity.java 上声明方法 "onButtonClick"，则以下回溯消失，但我收到另一个关于 "txt.length" 不能为空的回溯。 我的错误在哪里？谢谢 丹妮尔
将您的方法 'onButtonClick' 移动到您的 activity。
首先，onClick 方法应该出现在父 activity 中，这就是为什么在将代码移至 activity 时不会出现错误的原因class
或
如果你想把它放在你的片段中，那么你必须在片段中初始化按钮并为其设置 onClickListener，像这样：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout. fragment_scan,
container, false);
Button button = (Button) view.findViewById(R.id.btn_scansiona);
button.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
// do something
}
});
return view;
}
你得到 txt.length() can't be null error because :
- 您已将
txt定义为您的EditText而不是其中的文字。您必须像这样获取text并将其转换为String：txt.getText().toString()
然后你可以像这样进行正常处理:
txt.getText().toString().length()
而不是在布局中定义 ButtonClickListener 方法。你为什么不在代码中定义 buttonClickListener..
从布局和代码中删除 android:onClick 标签.. 使用
Button btnScan = view.findViewById(R.id.btn_scansiona
btnScan.onClickListener(.....){
//your rest code here....
}
欢迎丹妮尔
您必须在 activity 中定义该方法。
顺便说一句，如果您想以这种方式编写代码，我建议您使用 Butterknife 库。非常简单：
public class FancyFragment extends Fragment {
@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fancy_fragment, container, false);
ButterKnife.bind(this, view);
return view;
}
@OnClick(R.id.submit) public void submit(View view) {
// do something ... }
}
}
build.gradle
compile 'com.jakewharton:butterknife:8.1.0'
apt 'com.jakewharton:butterknife-compile