MainActivity.java
package com.example.myfirstapp;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.EditText;
import android.content.Intent;
public class MainActivity extends Activity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
/** Called when the user clicks the Send 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);
}
}
activitymain.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="horizontal" >
<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>
显示消息活动.java
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class DisplayMessageActivity extends ActionBarActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* 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_display_message,
container, false);
return rootView;
}
}
}
错误日志
04-10 01:37:00.460: W/dalvikvm(1650): threadid=1: thread exiting with uncaught exception (group=0xb3aaeba8)
04-10 01:37:00.520: E/AndroidRuntime(1650): FATAL EXCEPTION: main
04-10 01:37:00.520: E/AndroidRuntime(1650): Process: com.example.myfirstapp, PID: 1650
04-10 01:37:00.520: E/AndroidRuntime(1650): java.lang.IllegalStateException: Could not find a method sendMessage(View) in the activity class com.example.myfirstapp.MainActivity for onClick handler on view class android.widget.Button
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View$1.onClick(View.java:3810)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View.performClick(View.java:4438)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View$PerformClick.run(View.java:18422)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.os.Handler.handleCallback(Handler.java:733)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.os.Handler.dispatchMessage(Handler.java:95)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.os.Looper.loop(Looper.java:136)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.reflect.Method.invokeNative(Native Method)
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.reflect.Method.invoke(Method.java:515)
04-10 01:37:00.520: E/AndroidRuntime(1650): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-10 01:37:00.520: E/AndroidRuntime(1650): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-10 01:37:00.520: E/AndroidRuntime(1650): at dalvik.system.NativeStart.main(Native Method)
04-10 01:37:00.520: E/AndroidRuntime(1650): Caused by: java.lang.NoSuchMethodException: sendMessage [class android.view.View]
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.Class.getConstructorOrMethod(Class.java:472)
04-10 01:37:00.520: E/AndroidRuntime(1650): at java.lang.Class.getMethod(Class.java:857)
04-10 01:37:00.520: E/AndroidRuntime(1650): at android.view.View$1.onClick(View.java:3803)
04-10 01:37:00.520: E/AndroidRuntime(1650): ... 11 more
04-10 01:37:04.820: I/Process(1650): Sending signal. PID: 1650 SIG: 9
我试着看了看其他与我相似的问题,但我找不到一个似乎对我的情况有帮助的答案。有人能帮忙吗?
在android教程之后,我遇到了类似的错误
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myfirstapp, PID: 18300
java.lang.IllegalStateException: Could not find method sendMessage (MainActivity)(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'button'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:5197)
at android.view.View$PerformClick.run(View.java:20909)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5944)
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:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
但在我的案例中,所见即所得编辑器(IntelliJ w/Android Studio插件)最终在activity_main.xml中的onClick属性中填充了一些关于MainActivity:的额外垃圾
android:onClick="sendMessage (MainActivity)"
所以我删除了"(MainActivity)",它停止崩溃。我认为这与您的问题不同,因为您的xml文件在android:onClick="sendMessage"中似乎已经正确。但我想把它添加到这里,以供其他与我所看到的内容作斗争的人使用。这是我看到的最接近这个问题的帖子。我才刚开始,这让我很难过,所以希望它能帮助其他人。
问题是Button标签之一中的onClick属性:
android:onClick="sendMessage" />
只需确保在"活动"中有一个方法sendMessage(View)。
这是因为您需要在类中实现implements android.view.View.OnClickListener
,因此添加正确的导入,即import android.view.View
。