Android入门总结-Media

最近看了一下Android，只看书不总结一下，总感觉东西并没有放在脑子里，人过留名，雁过留声，遂写下这篇总结。

书本看的是《Android编程兵书》，但这篇总结的大纲是按照《第一行代码》的章节目录撰写的。两本书的内容结构大致相同，Android入门的话只看其中一本就够了。

使用通知：即可在activity中创建，也可在广播接收器中创建
PendingIntent：延迟执行的Intent
代码示例

NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
Notification notification = new Notification(R.drawable.ic_launcher, "This is a ticker text", System.currentTimeMillis());

Intent intent = new Intent(this, NotificationActivity.class);
PendingIntent pi = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT);

notification.setLatestEventInfo(this, "This is content title", "This is content text", pi);

Manager.notify(1, notification);    

// 第一个参数指定notification的id，在NotificationActivity中根据此ID取消通知
NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
manager.cancel(1);

通知的高级技巧：通过nofification的sound属性指定铃声；vibrate属性控制震动和静止的时长；ledARGB控制LED呼吸灯的颜色, ledOnMS指定灯亮起的时长，ledOffMS指定灯暗去的时长
示例：实现通知到来时LED灯以绿色的灯光一闪一闪

notification.ledARGB = Color.GREEN;
notification.ledOnMS = 1000;
notification.ledOffMS = 1000;
notification.flags = Notification.FLAG_SHOW_LIGHTS;

//也可完全根据当前手机的环境来决定播放的铃声以及震动
notification.defaults = Notification.DEFAULT_ALL;

接收和发送短信
接收短信:主要利用广播机制(有序广播)
示例代码

receiverFilter.setPriority(100);    // 提高优先级

Class MessageReceiver extends BroadcastReceiver{
    
    public void onReceive(Context context, Intent intent){
        Bundle bundle = intent.getExtras();
        Object[] pdus = (Object[])bundle.get("pdus");
        SmsMessage[] messages = new SmsMessage[pdus.length];

        for(int i = 0; i < SmsMessage.length; i++){
            messages[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
        }

        String address = message[0].getOriginationgAddress();
        String fullMessage = "";
        for(SmsMessage message : messages){
            fullMessage += message.getMessageBody();
        }
        sender.setText(address);
        content.setText(fullMessage);
        abortBroadcast();   // 中止广播继续传递
    }
}

调用摄像头和相册
调用摄像头示例代码

public class MainActivity extends Activity{
    
    public static final int TAKE_PHOTO = 1;
    public static final int CROP_PHOTO = 2;

    private Button takePhoto;
    private ImageView picture;
    private Uri iamgeUri;

    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        takePhoto = (Button)findViewById(R.id.takePhoto);

        picture = (ImageView)findViewById(R.id.picture);

        takePhoto.setOnclickListener(new OnClickListener(){
            public void onClick(View v){
                File outputImage = new File(Environment.getExternalStorageDirectory(), "output_image.jpg");
                try{
                    if(outputImage.exists()){
                        outputImage.delete();
                    }
                    outputImage.createNewFile();
                }catch(IOException e){
                    e.printStackTrace();
                }

                iamgeUri = Uri.fromFile(outputImage);
                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                intent.putExtra(MediaStore.EXTRA_OUTPUT, iamgeUri);
                startActivityForResult(intent, TAKE_PHOTO);
            }
        });
    }

    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        switch(requestCode){
        case TAKE_PHOTO:
            if(resultCode == RESULT_OK){
                Intent intent = new Intent("com.android.camera.cation.CROP");
                intent.setDataAndType(iamgeUri, "image/*");
                intent.putExtra("scale", true);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, iamgeUri);
                startActivityForResult(intent, CROP_PHOTO);
            }
            break;
        }

        case CROP_PHOTO:
            if(resultCode == RESULT_OK){
                try{
                    Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(iamgeUri));
                    picture.setImageBitmap(bitmap);
                }catch(FileNotFoundException e){
                    e.printStackTrace();
                }
            }
            break;
        default:
            break;
    }

}

从相册中选取照片

File outputImage = new File(Environment.getExtranalStorageDirectory(), "output_image.jpg");
try{
    if(outputImage.exists()){
        outputImage.delete();
    }
    outputImage.createNewFile();
}catch(IOException e){
    e.printStackTrace();
}
imageUri = Uri.fromFile(outputImage);
Intent intent = new Intent("android.intent.action.GET_CONTENT");
intent.setType("image/*");
intent.putExtra("crop", true);
intent.putExtra("scale", true);
intent.putExtra(MediaStore.EXTRA_OUTPUT, iamgeUri);
startActivityForResult(intent, CROP_PHOTO);

Tips
1、android 4.2 版本之后默认时把开发者选项隐藏掉的，进入关于手机界面，对版本号连击4次，即可开启开发者选项。