Android Server的bind()与unbind(),以及解绑异常
面试的时候被问到这样一个问题，绑定server之后如果不解绑，程序会Crash吗？我擦，蒙逼了，回去之后试了试，不会异常，但是会泄漏
1.异常一：先看一下报的异常吧
12-09 21:03:31.596 5771-5771/com.oblivion.changeactivity I/System.out: oncreate
12-09 21:03:31.596 5771-5771/com.oblivion.changeactivity I/System.out: onbind
12-09 21:03:34.816 5771-5771/com.oblivion.changeactivity E/ActivityThread: Activity com.oblivion.changeactivity.utils.MainActivity has leaked ServiceConnection com.oblivion.changeactivity.utils.MainActivity$MyConn@5281f840 that was originally bound here
android.app.ServiceConnectionLeaked: Activity com.oblivion.changeactivity.utils.MainActivity has leaked ServiceConnection com.oblivion.changeactivity.utils.MainActivity$MyConn@5281f840 that was originally bound here
at android.app.LoadedApk$ServiceDispatcher.(LoadedApk.java:970)
at android.app.LoadedApk.getServiceDispatcher(LoadedApk.java:864)
at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1577)
at android.app.ContextImpl.bindService(ContextImpl.java:1560)
at android.content.ContextWrapper.bindService(ContextWrapper.java:517)
at com.oblivion.changeactivity.utils.MainActivity.bind(MainActivity.java:26)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
12-09 21:03:34.816 5771-5771/com.oblivion.changeactivity I/System.out: onunbind
12-09 21:03:34.816 5771-5771/com.oblivion.changeactivity I/System.out: onDestroy
这种异常是直接bind之后退出程序（界面不可见出现问题，如果直接干掉程序是没问题的）
2.异常二,不绑定直接退出，也会出异常
同样看一叙异常
12-09 21:12:22.766 20054-20054/com.oblivion.changeactivity D/AndroidRuntime: Shutting down VM
12-09 21:12:22.766 20054-20054/com.oblivion.changeactivity W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xa4d27b20)
12-09 21:12:22.766 20054-20054/com.oblivion.changeactivity E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.oblivion.changeactivity, PID: 20054
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3823)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
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:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalArgumentException: connection is null
at android.app.ContextImpl.unbindService(ContextImpl.java:1608)
at android.content.ContextWrapper.unbindService(ContextWrapper.java:529)
at com.oblivion.changeactivity.utils.MainActivity.unbind(MainActivity.java:53)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method) 光说不练不怎么会体会到，我放一下完整代码,大家跑一下看看
<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="vertical"
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=".utils.MainActivity" >
<Button
android:onClick="bind"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="绑定服务" />
<Button
android:onClick="call"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="调用服务的方法" />
<Button
android:onClick="unbind"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="解除绑定服务" />
LinearLayout>MainActivity
package com.oblivion.changeactivity.utils;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import com.oblivion.changeactivity.R;
public class MainActivity extends Activity {
IService iService;
MyConn conn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void bind(View view) {
Intent intent = new Intent(this, TestService.class);
conn = new MyConn();
bindService(intent, conn, BIND_AUTO_CREATE);
}
private class MyConn implements ServiceConnection {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
iService = (IService) service;
}
@Override
public void onServiceDisconnected(ComponentName name) {
}
}
/**
* 调用借口方法
*
* @param view
*/
public void call(View view) {
iService.callMethodInService();
}
public void unbind(View view) {
unbindService(conn);
conn = null;
}
}
Server
package com.oblivion.changeactivity.utils;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.widget.Toast;
public class TestService extends Service {
private class MyBinder extends Binder implements IService {
@Override
public void callMethodInService() {
methodInService();
}
}
private void methodInService() {
Toast.makeText(this, "调用Bind方法", Toast.LENGTH_SHORT).show();
}
@Override
public IBinder onBind(Intent intent) {
System.out.println("onbind");
return new MyBinder();
}
@Override
public boolean onUnbind(Intent intent) {
System.out.println("onunbind");
return super.onUnbind(intent);
}
@Override
public void onStart(Intent intent, int startId) {
System.out.println("onstart");
super.onStart(intent, startId);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
System.out.println("onStartCommand");
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onCreate() {
System.out.println("oncreate");
super.onCreate();
}
@Override
public void onDestroy() {
System.out.println("onDestroy");
super.onDestroy();
}
}
Iserver接口
package com.oblivion.changeactivity.utils;
public interface IService {
/**
* 服务方法
*/
public void callMethodInService();
}
不要忘记在清单中配置
<service android:name=".utils.TestService">service>