错误“无法执行android:onClick的方法"； [英] Error "Could not execute method for android:onClick"
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问题描述
我想通过sql来登录按钮.运行应用程序时，出现onclick错误:
I want to make login button by sql. When I run the app, I have an onclick error:
Process: com.example.mosab.hostlent, PID: 31057
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5609)
at android.view.View$PerformClick.run(View.java:22263)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5609)
at android.view.View$PerformClick.run(View.java:22263)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
at com.example.mosab.hostlent.login.loginon(login.java:92)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5609)
at android.view.View$PerformClick.run(View.java:22263)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
这是我的点击代码:
public void loginon(View v) {
String Email = email.getText().toString().trim();
String Password = password.getText().toString().trim();
String type = "login";
worker worker = new worker(this);
worker.execute(type,Email,Password);
}
这是我的xml文件:
<ImageButton
android:id="@+id/login"
android:layout_width="205dp"
android:layout_height="50dp"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:background="@color/hostlent"
android:baselineAlignBottom="false"
android:contextClickable="false"
android:cropToPadding="false"
android:keepScreenOn="false"
android:nestedScrollingEnabled="false"
android:onClick="loginon"
android:saveEnabled="false"
android:scaleType="fitCenter"
app:srcCompat="@drawable/login"
tools:layout_editor_absoluteX="86dp"
tools:layout_editor_absoluteY="332dp" />
我的课程由onclick代码调用:
public class worker extends AsyncTask<String,Void,String> {
Context context ;
AlertDialog alertDialog;
worker (Context context){
Context ctx;
}
@Override
protected String doInBackground(String... params) {
String type = params[0];
String login_url = "http://192.168.1.239:8080/login.php";
if (type.equals("login")){
try {
String email = params[1];
String password = params[2];
URL url = new URL(login_url);
HttpsURLConnection httpsURLConnection = (HttpsURLConnection)url.openConnection();
httpsURLConnection.setRequestMethod("post");
httpsURLConnection.setDoOutput(true);
httpsURLConnection.setDoInput(true);
OutputStream outputStream = httpsURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
String post_data = URLEncoder.encode("email","UTF-8")+"="+URLEncoder.encode(email,"UTF-8")+"&"+URLEncoder.encode(password,"UTF-8");
bufferedWriter.write(post_data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();
InputStream inputStream = httpsURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream,"iso-8859-1"));
String result="";
String line="";
while ((line=bufferedReader.readLine())!=null){
result += line;
}
bufferedReader.close();
inputStream.close();
httpsURLConnection.disconnect();
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
@Override
protected void onPreExecute() {
alertDialog=new AlertDialog.Builder(context).create();
alertDialog.setTitle("login status");
}
@Override
protected void onPostExecute(String result) {
alertDialog.setMessage(result);
alertDialog.show();
}
@Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
，我正在清单文件中添加以下代码:
<uses-permission android:name="android.permission.INTERNET"></uses-permission>"
您能帮助我了解我的错误是什么吗?
Can you help me to understand which is my error?
推荐答案
以下两行之一出现错误，
The error is in either one of the following 2 lines,
String Email = email.getText().toString().trim();
String Password = password.getText().toString().trim();
变量email或password为null.您需要在onCreate()方法中将这些变量设置为适当的edittext字段.
Either the variable email or password is null. You need to set these variables to appropriate edittext fields in your onCreate() method.
如果仍然无法解决问题，请使用完整的代码将其更新为您的活动和布局文件xml.
If you are still unable to solve the issue, update the question with full code to your activity and the layout file xml.
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