在Android培训篇之App交互类Intent中已经详细介绍过Intent的基础知识。这里就不再对Intent进行介绍，而是重点介绍系统自带的常用Intent。

1. 闹钟和秒表

启动闹钟的Intent示意如下：

public void createAlarm(String message, int hour, int minutes) {

    Intent intent = new Intent(AlarmClock.ACTION_SET_ALARM)
            .putExtra(AlarmClock.EXTRA_MESSAGE, message)
            .putExtra(AlarmClock.EXTRA_HOUR, hour)
            .putExtra(AlarmClock.EXTRA_MINUTES, minutes);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivity(intent);
    }   
}

启动秒表的Intent示意如下：

public void startTimer(String message, int seconds) {
    Intent intent = new Intent(AlarmClock.ACTION_SET_TIMER)
            .putExtra(AlarmClock.EXTRA_MESSAGE, message)
            .putExtra(AlarmClock.EXTRA_LENGTH, seconds)
            .putExtra(AlarmClock.EXTRA_SKIP_UI, true);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivity(intent);
    }
}

需要注意的是：无论是闹钟还是秒表，都需要在manifest中添加SET_ALARM权限。

<uses-permission android:name="com.android.alarm.permission.SET_ALARM" />

2. 行程

点击查看：行程的测试源码

添加行程的Intent示意如下：

public void addEvent(String title, String location, Calendar begin, Calendar end) {
    Intent intent = new Intent(Intent.ACTION_INSERT)
            .setData(Events.CONTENT_URI)
            .putExtra(Events.TITLE, title)
            .putExtra(Events.EVENT_LOCATION, location)
            .putExtra(CalendarContract.EXTRA_EVENT_BEGIN_TIME, begin)
            .putExtra(CalendarContract.EXTRA_EVENT_END_TIME, end);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivity(intent);
    }   
}

3. 拍照并获取所拍的图片

点击查看：获取拍照图片的测试源码

3.1 打开Camera进行拍照

public void capturePhoto() {

    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);  

    ContentValues values = new ContentValues();
    values.put(MediaStore.Images.Media.DISPLAY_NAME, "MyImage");  
    values.put(MediaStore.Images.Media.DESCRIPTION, "this is description");  
    values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");  
    mLocationForPhotos = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);  
    intent.putExtra(MediaStore.EXTRA_OUTPUT, mLocationForPhotos);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
    }   
}

3.2 获取拍照的图片

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        try {
            // 首先取得屏幕对象  
            Display display = getWindowManager().getDefaultDisplay();
            // 获取屏幕的宽和高  
            int dw = display.getWidth();
            int dh = display.getHeight();
            // 获取图片原始大小
            BitmapFactory.Options op = new BitmapFactory.Options();
            op.inJustDecodeBounds = true;
            Bitmap pic = BitmapFactory.decodeStream(
                    this.getContentResolver().openInputStream(mLocationForPhotos),
                    null, op);

            int wRatio = (int) Math.ceil(op.outWidth / (float) dw); //计算宽度比例  
            int hRatio = (int) Math.ceil(op.outHeight / (float) dh); //计算高度比例  
            Log.d(TAG, "wRatio="+wRatio+", hRatio="+hRatio);
            // 设置缩放比例
            if (wRatio > 1 && hRatio > 1) {
                if (wRatio > hRatio) {
                    op.inSampleSize = wRatio;
                } else {
                    op.inSampleSize = hRatio;
                }
            } else {
                op.inSampleSize = 4; // 默认缩小为4倍 
            }

            op.inJustDecodeBounds = false; //注意这里，一定要设置为false，因为上面我们将其设置为true来获取图片尺寸了  
            pic = BitmapFactory.decodeStream(this.getContentResolver().openInputStream(mLocationForPhotos),
                    null, op);
            mImage.setImageBitmap(pic);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4. 获取联系人

点击查看：获取联系人的测试源码

下面给出获取联系人号码的示例：

public void selectContact() {
    // Start an activity for the user to pick a phone number from contacts
    Intent intent = new Intent(Intent.ACTION_PICK);
    intent.setType(CommonDataKinds.Phone.CONTENT_TYPE);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(intent, REQUEST_SELECT_PHONE_NUMBER);
    }   
}

说明：上面函数的作用是选取一个联系人。选取联系人之后，再提取出联系人号码。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_SELECT_PHONE_NUMBER && resultCode == RESULT_OK) {
        // Get the URI and query the content provider for the phone number
        Uri contactUri = data.getData();
        String[] projection = new String[]{CommonDataKinds.Phone.NUMBER};
        Cursor cursor = getContentResolver().query(contactUri, projection,
                null, null, null);
        // If the cursor returned is valid, get the phone number
        if (cursor != null && cursor.moveToFirst()) {
            int numberIndex = cursor.getColumnIndex(CommonDataKinds.Phone.NUMBER);
            String number = cursor.getString(numberIndex);
            Log.d(TAG, "number="+number);
        }   
    }   
}

5. Email

点击查看：Email的测试源码

打开Email程序的示意非常简单：

public void composeEmail(String[] addresses, String subject, Uri attachment) {
    Intent intent = new Intent(Intent.ACTION_SEND);
    intent.setType("*/*");
    intent.putExtra(Intent.EXTRA_EMAIL, addresses);
    intent.putExtra(Intent.EXTRA_SUBJECT, subject);
    intent.putExtra(Intent.EXTRA_STREAM, attachment);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivity(intent);
    }   
}

6. 从图库中选择图片

点击查看：从图库中选择图片的测试源码

6.1 选择图片

public void selectImage() {
    //Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
    intent.setType("image/*");
    intent.addCategory(Intent.CATEGORY_OPENABLE);

    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(intent, REQUEST_IMAGE_GET);
    }   
}

6.2 读取所选择的图片

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (requestCode == REQUEST_IMAGE_GET && resultCode == RESULT_OK) {

        try {   
            Uri mLocationForPhotos = data.getData();
            // 首先取得屏幕对象  
            Display display = getWindowManager().getDefaultDisplay();  
            // 获取屏幕的宽和高  
            int dw = display.getWidth();  
            int dh = display.getHeight();  
            // 获取图片原始大小
            BitmapFactory.Options op = new BitmapFactory.Options();  
            op.inJustDecodeBounds = true;  
            Bitmap pic = BitmapFactory.decodeStream(
                    this.getContentResolver().openInputStream(mLocationForPhotos),
                    null, op);

            int wRatio = (int) Math.ceil(op.outWidth / (float) dw); //计算宽度比例  
            int hRatio = (int) Math.ceil(op.outHeight / (float) dh); //计算高度比例  
            Log.d(TAG, "wRatio="+wRatio+", hRatio="+hRatio);
            // 设置缩放比例
            if (wRatio > 1 && hRatio > 1) {
                if (wRatio > hRatio) {
                    op.inSampleSize = wRatio;
                } else {
                    op.inSampleSize = hRatio;
                }
            } else {
                op.inSampleSize = 4; // 默认缩小为4倍 
            }

            op.inJustDecodeBounds = false; //注意这里，一定要设置为false，因为上面我们将其设置为true来获取图片尺寸了  
            pic = BitmapFactory.decodeStream(this.getContentResolver().openInputStream(mLocationForPhotos),
                    null, op);
            mImage.setImageBitmap(pic);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

7. 打开网页

点击查看：网页的测试源码

public void openWebPage(String url) {
    Uri webpage = Uri.parse(url);
    Intent intent = new Intent(Intent.ACTION_VIEW, webpage);
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivity(intent);
    }   
}

2014-06-21 09:11:00 by skywang

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