Android通过RemoteViews实现跨进程更新UI

一、概述

前面一篇文章Android通过AIDL实现跨进程更新UI我们学习了aidl跨进程更新ui，这种传统方式实现跨进程更新UI是可行的，但有以下弊端：

• View中的方法数比较多，在IPC中需要增加对应的方法比较繁琐。
• View的每一个方法都会涉及到IPC操作，多次IPC带来的开销问题不容小觑。
• View中方法的某些参数可能不支持IPC传输。例如：OnClickListener，它仅仅是个接口没有序列化。

接下来我们通过RemoteViews实现跨进程更新UI

二、实现效果图

在同一个应用中有两个Activity，MainActivity和Temp2Activity，这两个Activity不在同一个进程中。

现在需要通过Temp2Activity来改变MainActivity中的视图，即在MainActivity中添加两个Button，也就是实现跨进程更新UI这么一个功能。

在MainActivity里点击“跳转到新进程ACTIVITY”按钮，会启动一个新进程的Temp2Activity，我们先点击“绑定服务”，这样我们就启动了服务，再点击“AIDL更新”按钮，通过调用handler来实现跨进程更新UI，点击返回，我们发现MainActivity页面中新添加了两个按钮，并且按钮还具有点击事件。

三、核心代码

IremoteViewsManager.aidl

// IremoteViewsManager.aidl.aidlpackage com.czhappy.remoteviewdemo;interface IremoteViewsManager {    void addRemoteView(in RemoteViews remoteViews);}

RemoteViewsAIDLService.java

package com.czhappy.remoteviewdemo.service;import android.app.Service;import android.content.Intent;import android.os.Binder;import android.os.Bundle;import android.os.IBinder;import android.os.Message;import android.os.RemoteException;import android.widget.RemoteViews;import com.czhappy.remoteviewdemo.IremoteViewsManager;import com.czhappy.remoteviewdemo.activity.MainActivity;/** * Description: * User: chenzheng * Date: 2017/2/10 0010 * Time: 10:56 */public class RemoteViewsAIDLService extends Service {    private static final String TAG = "RemoteViewsAIDLService";    private Binder remoteViewsBinder = new IremoteViewsManager.Stub(){        @Override        public void addRemoteView(RemoteViews remoteViews) throws RemoteException {            Message message = new Message();            message.what = 1;            Bundle bundle = new Bundle();            bundle.putParcelable("remoteViews",remoteViews);            message.setData(bundle);            new MainActivity.MyHandler(RemoteViewsAIDLService.this,getMainLooper()).sendMessage(message);        }    };    public RemoteViewsAIDLService() {    }    @Override    public IBinder onBind(Intent intent) {        return remoteViewsBinder;    }}

MainActivity.java

package com.czhappy.remoteviewdemo.activity;import android.content.Context;import android.content.Intent;import android.os.Bundle;import android.os.Handler;import android.os.Looper;import android.os.Message;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.widget.LinearLayout;import android.widget.RemoteViews;import android.widget.TextView;import com.czhappy.remoteviewdemo.R;import java.lang.ref.WeakReference;public class MainActivity extends AppCompatActivity {    private static String TAG = "MainActivity";    private static LinearLayout mLinearLayout;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mLinearLayout = (LinearLayout) this.findViewById(R.id.mylayout);    }    public static class MyHandler extends Handler {        WeakReference<Context> weakReference;        public MyHandler(Context context, Looper looper) {            super(looper);            weakReference = new WeakReference<>(context);        }        @Override        public void handleMessage(Message msg) {            super.handleMessage(msg);            Log.i(TAG, "handleMessage");            switch (msg.what) {                case 1: //RemoteViews的AIDL实现                    RemoteViews remoteViews = msg.getData().getParcelable("remoteViews");                    if (remoteViews != null) {                        Log.i(TAG, "updateUI");                        View view = remoteViews.apply(weakReference.get(), mLinearLayout);                        mLinearLayout.addView(view);                    }                    break;                default:                    break;            }        }    };    public void readyGo(View view){        Intent intent = new Intent(MainActivity.this, Temp2Activity.class);        startActivity(intent);    }}

Temp2Activity.java

package com.czhappy.remoteviewdemo.activity;import android.app.PendingIntent;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.os.RemoteException;import android.support.annotation.Nullable;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.widget.RemoteViews;import com.czhappy.remoteviewdemo.IremoteViewsManager;import com.czhappy.remoteviewdemo.R;import com.czhappy.remoteviewdemo.service.RemoteViewsAIDLService;/** * Description: * User: chenzheng * Date: 2017/2/9 0009 * Time: 16:05 */public class Temp2Activity extends AppCompatActivity {    private String TAG = "Temp2Activity";    private IremoteViewsManager remoteViewsManager;    private boolean isBind = false;    private ServiceConnection remoteViewServiceConnection = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            Log.i(TAG,"onServiceConnected");            remoteViewsManager = IremoteViewsManager.Stub.asInterface(service);        }        @Override        public void onServiceDisconnected(ComponentName name) {            //回收            remoteViewsManager = null;        }    };    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        this.setContentView(R.layout.activity_temp);    }    /**     * 绑定服务     */    public void bindService(View view) {        Intent viewServiceIntent = new Intent(this,RemoteViewsAIDLService.class);        isBind = bindService(viewServiceIntent,remoteViewServiceConnection, Context.BIND_AUTO_CREATE);    }    /**     * 更新UI     */    public void UpdateUI(View view){        RemoteViews remoteViews = new RemoteViews(Temp2Activity.this.getPackageName(),R.layout.button_layout);        Intent intentClick = new Intent(Temp2Activity.this,FirstActivity.class);        PendingIntent openFirstActivity = PendingIntent.getActivity(Temp2Activity.this,0,intentClick,0);        remoteViews.setOnClickPendingIntent(R.id.firstButton,openFirstActivity);        Intent secondClick = new Intent(Temp2Activity.this,SecondActivity.class);        PendingIntent openSecondActivity = PendingIntent.getActivity(Temp2Activity.this,0,secondClick,0);        remoteViews.setOnClickPendingIntent(R.id.secondButton,openSecondActivity);        remoteViews.setCharSequence(R.id.secondButton,"setText","想改就改");        try {            remoteViewsManager.addRemoteView(remoteViews);        } catch (RemoteException e) {            e.printStackTrace();        }    }    @Override    protected void onDestroy() {        super.onDestroy();        if(isBind){            unbindService(remoteViewServiceConnection);            isBind = false;        }    }}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.czhappy.remoteviewdemo">    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".activity.MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <activity android:name=".activity.FirstActivity" />        <activity android:name=".activity.SecondActivity" />        <activity            android:name=".activity.Temp2Activity"            android:process=":remote2" />        <service android:name="com.czhappy.remoteviewdemo.service.RemoteViewsAIDLService" />    </application></manifest>

四、总结

RemoteViews就是为跨进程更新UI而生的，内部封装了很多方法用来实现跨进程更新UI。但这并不代表RemoteViews是就是万能的了，它也有不足之处，目前支持的布局和View有限
layout：
FrameLayout LinearLayout RelativeLayout GridLayout
View：
AnalogClock button Chronometer ImageButton ImageView ProgressBar TextView ViewFlipper ListView GridView StackView AdapterViewFlipper ViewStub

不支持自定义View 所以具体使用RemoteViews还是aidl或者BroadCastReceiver还得看实际的需求。