4.2.1.1.md

4.2.1.1 私有广播接收器

私人广播接收器是最安全的广播接收器，因为只能接收到从应用内发送的广播。 动态广播接收器不能注册为私有，所以私有广播接收器只包含静态广播接收器。

要点（接收广播）：

1. 将导出属性显示设为false

2. 小心并安全地处理收到的意图，即使意图从相同的应用中发送

3. 敏感信息可以作为返回结果发送，因为请求来自相同应用

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.jssec.android.broadcast.privatereceiver" >
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:allowBackup="false" >
        <!-- Private Broadcast Receiver -->
        <!-- *** POINT 1 *** Explicitly set the exported attribute to false. -->
        <receiver
        android:name=".PrivateReceiver"
        android:exported="false" />
        <activity
            android:name=".PrivateSenderActivity"
            android:label="@string/app_name"
            android:exported="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

PrivateReceiver.java

package org.jssec.android.broadcast.privatereceiver;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;
public class PrivateReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        // *** POINT 2 *** Handle the received intent carefully and securely,
        // even though the intent was sent from within the same application.
        // Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
        String param = intent.getStringExtra("PARAM");
        Toast.makeText(context,
        String.format("Received param: ¥"%s¥"", param),
        Toast.LENGTH_SHORT).show();
        // *** POINT 3 *** Sensitive information can be sent as the returned results since the requests come from within the same application.
        setResultCode(Activity.RESULT_OK);
        setResultData("Sensitive Info from Receiver");
        abortBroadcast();
    }
}

向私有广播接收器发送广播的代码展示在下面：

要点（发送广播）：

1. 使用带有指定类的显式意图，来调用相同应用中的接收器。

2. 敏感信息可以发送，因为目标接收器在相同应用中。

3. 小心并安全地处理收到的返回结果，即使数据来自相同应用中的接收器。

PrivateSenderActivity.java

package org.jssec.android.broadcast.privatereceiver;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class PrivateSenderActivity extends Activity {
    public void onSendNormalClick(View view) {
        // *** POINT 4 *** Use the explicit Intent with class specified to call a receiver within the same application.
        Intent intent = new Intent(this, PrivateReceiver.class);
        // *** POINT 5 *** Sensitive information can be sent since the destination Receiver is within the same application.
        intent.putExtra("PARAM", "Sensitive Info from Sender");
        sendBroadcast(intent);
    }
    public void onSendOrderedClick(View view) {
        // *** POINT 4 *** Use the explicit Intent with class specified to call a receiver within the same application.
        Intent intent = new Intent(this, PrivateReceiver.class);
        // *** POINT 5 *** Sensitive information can be sent since the destination Receiver is within the same application.
        intent.putExtra("PARAM", "Sensitive Info from Sender");
        sendOrderedBroadcast(intent, null, mResultReceiver, null, 0, null, null);
    }
    private BroadcastReceiver mResultReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // *** POINT 6 *** Handle the received result data carefully and securely,
            // even though the data came from the Receiver within the same application.
            // Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
            String data = getResultData();
            PrivateSenderActivity.this.logLine(
                String.format("Received result: ¥"%s¥"", data));
        }
    };
    private TextView mLogView;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mLogView = (TextView)findViewById(R.id.logview);
    }
    private void logLine(String line) {
        mLogView.append(line);
        mLogView.append("¥n");
    }
}