当我按下
fragment_main.xml
中的按钮时,出现此错误:java.lang.IllegalStateException: Could not find a method sendMessage(View) in the activity class com.example.alexander.mobileapp02.MainActivity for onClick handler on view class android.widget.Button
02-09 21:01:39.271 13128-13128/com.example.alexander.mobileapp02 D/AndroidRuntime﹕ Shutting down VM
02-09 21:01:39.271 13128-13128/com.example.alexander.mobileapp02 W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41bd4c08)
02-09 21:01:39.281 13128-13128/com.example.alexander.mobileapp02 E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.alexander.mobileapp02, PID: 13128
java.lang.IllegalStateException: Could not find a method sendMessage(View) in the activity class com.example.alexander.mobileapp02.MainActivity for onClick handler on view class android.widget.Button
at android.view.View$1.onClick(View.java:3970)
at android.view.View.performClick(View.java:4654)
at android.view.View$PerformClick.run(View.java:19438)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5602)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NoSuchMethodException: sendMessage [class android.view.View]
at java.lang.Class.getConstructorOrMethod(Class.java:472)
at java.lang.Class.getMethod(Class.java:857)
at android.view.View$1.onClick(View.java:3963)
at android.view.View.performClick(View.java:4654)
at android.view.View$PerformClick.run(View.java:19438)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5602)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
02-09 21:01:46.121 13128-13128/com.example.alexander.mobileapp02 I/Process﹕ Sending signal. PID: 13128 SIG: 9
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity$PlaceholderFragment"
android:background="#A9F5F2">
<EditText android:id="@+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="@string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send"
android:onClick="sendMessage" />
</LinearLayout>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container"
android:layout_width="match_parent" android:layout_height="match_parent"
tools:context=".MainActivity" tools:ignore="MergeRootFrame" />
package com.example.alexander.mobileapp02;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
import android.widget.ImageButton;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
configureImageButton();
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
//}
private void configureImageButton() {
/*
ImageButton btn = (ImageButton) findViewById(R.id.imageButton);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, "You clicked the button!", Toast.LENGTH_LONG.show());
// change image on button 123
ImageButton btn = (ImageButton) findViewById(R.id.imageButton);
btn.setImageResource(R.drawable.example_two);
}
});
//*/
/*
ImageButton button = (ImageButton) findViewById(R.id.imageButton);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
//
ImageButton btn = (ImageButton) findViewById(R.id.imageButton);
btn.setImageResource(R.drawable.example_two);
}
});
//*/
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
}
package com.example.alexander.mobileapp02;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.EditText;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.widget.EditText;
public class MyActivity extends ActionBarActivity {
public final static String EXTRA_MESSAGE = "com.example.alexander.mobileapp02.MESSAGE";
/** Pressing the start button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
fragment_main.xml 显示按钮以及您可以输入姓名的位置。
activity_main.xml 什么都不是(只是一个带有“Hello world!”的空白页面
现在这很重要。 activity_display_message.xml
本链接末尾的教程说明 ( ) “您现在可以运行该应用程序。当它打开时,在文本字段中键入一条消息,单击发送,该消息将出现在第二个活动上。”
但是当我输入内容并按下按钮时,我的应用程序崩溃并收到上面输入的错误。
有人可以帮忙吗?
伙计,错误很明显 -
在活动类中找不到方法 sendMessage(View) com.example.alexander.mobileapp02.MainActivity
当你在 XML 中声明这样一行时 -
android:onClick="sendMessage"
您需要创建在您的
MainActivity
中执行的方法,它将调用它的View
作为参数。
public void sendMessage(View myView)
{
//Your code here
}
将此添加到您的
MainActivity
中,而不是您的MyActivity
中,然后填写执行sendMessage
的代码。这不是魔法。