点击按钮获取IllegalStateException [英] Getting IllegalStateException on button click
本文介绍了点击按钮获取IllegalStateException的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
单击按钮以迁移到另一个活动时，应用程序崩溃并显示日志:
On clicking a button to migrate to another activity, the app crashes and log shows:
java.lang.IllegalStateException: Could not execute method for android:onClick
要进行调试，我尝试迁移到空白活动，但仍然显示相同的错误.不明白为什么！
To debug, I tried to migrate to a blank activity still it shows the same error. Can't understand why!
这是我的主要活动java文件，它在host()的intent函数中显示错误:
This is my main activity java file and it shows error in host()'s intent function:
package com.example.unholyalliance.infinitestream;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void host(View v)
{
Intent i = new Intent(this,Host.class);
try
{
startActivity(i);
}catch(IllegalStateException e)
{
Context context = getApplicationContext();
CharSequence text = e.getMessage();
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
}
public void search(View v)
{
}
}
This is my Host.java file:
import android.content.Context;
import android.net.nsd.NsdManager;
import android.net.nsd.NsdServiceInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import java.io.IOException;
import java.net.ServerSocket;
public class Host extends AppCompatActivity {
public String mServiceName="Stream";
ServerSocket mServerSocket=null;
NsdManager.RegistrationListener mRegistrationListener=null;
private NsdManager mNsdManager=null;
int port=9000;
TextView service_status = (TextView) findViewById(R.id.textView1);
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_host);
mNsdManager = (NsdManager) getSystemService(Context.NSD_SERVICE);
try {
initializeServerSocket();
} catch (IOException e) {
e.printStackTrace();
}
}
public void initializeServerSocket() throws IOException {
//Initialize a server socket on the next available port.
mServerSocket = new ServerSocket(0);
// Store the chosen port.
port = mServerSocket.getLocalPort();
registerService(port);
}
public void registerService(int port) {
// Create the NsdServiceInfo object, and populate it.
NsdServiceInfo serviceInfo = new NsdServiceInfo();
// The name is subject to change based on conflicts
// with other services advertised on the same network.
serviceInfo.setServiceName("Stream");
serviceInfo.setServiceType("_http._tcp.");
serviceInfo.setPort(port);
mNsdManager.registerService(
serviceInfo, NsdManager.PROTOCOL_DNS_SD, mRegistrationListener);
initializeRegistrationListener();
}
public void initializeRegistrationListener() {
mRegistrationListener = new NsdManager.RegistrationListener() {
@Override
public void onServiceRegistered(NsdServiceInfo NsdServiceInfo) {
// Save the service name. Android may have changed it in order to
// resolve a conflict, so update the name you initially requested
// with the name Android actually used.
mServiceName = NsdServiceInfo.getServiceName();
service_status.setText("Success");
}
@Override
public void onRegistrationFailed(NsdServiceInfo serviceInfo, int errorCode) {
// Registration failed! Put debugging code here to determine why.
service_status.setText("Registration Failed!");
}
@Override
public void onServiceUnregistered(NsdServiceInfo arg0) {
// Service has been unregistered. This only happens when you call
// NsdManager.unregisterService() and pass in this listener.
service_status.setText("Registration not done");
}
@Override
public void onUnregistrationFailed(NsdServiceInfo serviceInfo, int errorCode) {
// Unregistration failed. Put debugging code here to determine why.
service_status.setText("Unregistration failed");
}
};
}
}
完整堆栈跟踪:
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:4278)
at android.view.View$PerformClick.run(View.java:17429)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5099)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:803)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:570)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4278)
at android.view.View$PerformClick.run(View.java:17429)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5099)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:803)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:570)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.unholyalliance.infinitestream/com.example.unholyalliance.infinitestream.Host}; have you declared this activity in your AndroidManifest.xml?
at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1633)
at android.app.Instrumentation.execStartActivity(Instrumentation.java:1425)
at android.app.Activity.startActivityForResult(Activity.java:3370)
at android.app.Activity.startActivityForResult(Activity.java:3331)
at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:843)
at android.app.Activity.startActivity(Activity.java:3566)
at android.app.Activity.startActivity(Activity.java:3534)
at com.example.unholyalliance.infinitestream.MainActivity.host(MainActivity.java:23)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4278)
at android.view.View$PerformClick.run(View.java:17429)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5099)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:803)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:570)
at dalvik.system.NativeStart.main(Native Method)
activity_main.xml文件:
activity_main.xml file:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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.example.unholyalliance.infinitestream.MainActivity">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Host"
android:id="@+id/host_button"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="104dp"
android:clickable="true"
android:onClick="host" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search"
android:id="@+id/search_button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:onClick="search"
android:clickable="true" />
</RelativeLayout>
推荐答案
完整堆栈跟踪的关键部分位于:
The key part of the full stack trace is found here:
原因:android.content.ActivityNotFoundException:无法找到 显式活动课 {com.example.unholyalliance.infinitestream/com.example.unholyalliance.infinitestream.Host}； 您是否在AndroidManifest.xml中声明了此活动
Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.unholyalliance.infinitestream/com.example.unholyalliance.infinitestream.Host}; have you declared this activity in your AndroidManifest.xml
似乎您的清单文件中没有声明此Host活动.打开AndroidManifest.xml并检查或添加以下内容:
It appears you do not have this Host activity declared in your manifest file. Open AndroidManifest.xml and check for or add the following:
<activity
android:name=".Host" />
还请确保已解决Host中的问题，以首先仅声明TextView，然后在setContentView()之后分配onCreate()中的值.
Also make sure you fix the issue in Host to first only declare your TextView and then assign the value in onCreate() after setContentView().
private TextView service_status;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_host);
service_status = (TextView) findViewById(R.id.textView1);
...
}
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