如何借助广播接收器获取相机点击事件？

Question

我不想制作任何应用程序。我只希望当我点击默认的相机应用程序（附有屏幕截图）时，它通常会打开相机。然后，当我单击用于单击图像的按钮时，我只想显示 A Toast。为此，我尝试了一些东西。我只是试图接收广播意图。代码如下。但我没有得到吐司。请帮我。

MainActivity.java

public class MainActivity extends Activity {

    CameraReceiver myReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Intent intent = new Intent("com.android.camera.NEW_PICTURE");
        CameraReceiver myReceiver = new CameraReceiver();
        sendBroadcast(intent);
    }

    private class CameraReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            abortBroadcast();
            Log.d("New Photo Clicked", ">");
            Cursor cursor = context.getContentResolver().query(
                    intent.getData(), null, null, null, null);
            cursor.moveToFirst();
            String image_path = cursor
                    .getString(cursor.getColumnIndex("_data"));
            Toast.makeText(getApplicationContext(), "New Photo is Saved as : " + image_path,
                    1000).show();
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        myReceiver = new CameraReceiver();
        IntentFilter i = new IntentFilter("android.intent.action.CAMERA_BUTTON");
        registerReceiver(myReceiver, i);
    }

    @Override 
    public void onResume() {
        IntentFilter i = new IntentFilter("android.intent.action.CAMERA_BUTTON");
        registerReceiver(myReceiver, i);
        super.onResume();
    }

    @Override 
    public void onPause() {
        unregisterReceiver(myReceiver);
        super.onPause();
    }
}

AndroidManifest.xml

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.example.defaultcamers.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.DEFAULT" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <receiver
        android:name=".CameraReceiver"
        android:enabled="true" >
        <intent-filter android:priority="10000">
            <action android:name="android.intent.action.CAMERA_BUTTON" />
            <action android:name="com.android.camera.NEW_PICTURE" />
            <action android:name="android.hardware.action.NEW_PICTURE" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="image/*" />
        </intent-filter>
    </receiver>
    <class android:name=".CameraReceiver" >
    </class>
</application>

现在，当我打开相机并尝试单击图片时，我在“CameraReceiver.java”中得到“ClassNotFound Excaption”。

Answer 1

我通过公开 CameraReceiver 类解决了 ClassNotFoundException。我在我的 android 项目上实现了你的代码，并得到了 ClassNotFoundException 但我现在解决了。只需按以下方式更改您的类，并像我在以下代码中所做的那样更改 Toast 的第一个参数。

public class CameraReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub 
        abortBroadcast();
        Log.d("New Photo Clicked", ">");
        Cursor cursor = context.getContentResolver().query(
            intent.getData(), null, null, null, null);
        cursor.moveToFirst();
        String image_path = cursor
            .getString(cursor.getColumnIndex("_data"));
        Toast.makeText(context, "New Photo is Saved as : " + image_path,
            1000).show();
    }

}

当我从相机拍照时，它应该工作，它对我有用。从 MainActivity 中删除该类并为上述代码创建一个单独的公共 CameraReceiver 类。