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Android:SNS客户端开发七:发送带图片的微博(一)(调用相机和Gallery获得照片)

2012-07-09 11:26 459 查看
之前已经介绍了如何发布一条文字微博,接下来的两篇文章会介绍如何发送带图片的微博。今天先看如何调用照相或者Gallery来获取我们想要发送图片文件。

第一步,看需要申明的几个值

Java代码







private String picPath;//文件路径

private static final int PHOTO_WITH_CAMERA = 1010;// 拍摄照片

private static final int PHOTO_WITH_DATA = 1020;// 从SD中得到照片

private static final File PHOTO_DIR = new File(
Environment.getExternalStorageDirectory() + "/DCIM/Camera");//拍摄照片存储的文件夹路劲

private File capturefile;//拍摄的照片文件

private String picPath;//文件路径
private static final int PHOTO_WITH_CAMERA = 1010;// 拍摄照片
private static final int PHOTO_WITH_DATA = 1020;// 从SD中得到照片
private static final File PHOTO_DIR = new File(
Environment.getExternalStorageDirectory() + "/DCIM/Camera");//拍摄照片存储的文件夹路劲
private File capturefile;//拍摄的照片文件


第二步,选择获取图片方式的对话框实现

Java代码







final Context dialogContext = new ContextThemeWrapper(context,
android.R.style.Theme_Light);
String[] choices;
choices = new String[2];
choices[0] = "相机拍摄"; // 拍照

choices[1] = "本地相册"; // 从相册中选择

final ListAdapter adapter = new ArrayAdapter<String>(dialogContext,
android.R.layout.simple_list_item_1, choices);

final AlertDialog.Builder builder = new AlertDialog.Builder(
dialogContext);
builder.setTitle("添加图片");
builder.setSingleChoiceItems(adapter, -1,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
switch (which) {
case 0: {
String status = Environment
.getExternalStorageState();
if (status.equals(Environment.MEDIA_MOUNTED)) {// 判断是否有SD卡

Intent i = new Intent(
MediaStore.ACTION_IMAGE_CAPTURE);
capturefile = new File(PHOTO_DIR,
getPhotoFileName());
try {
capturefile.createNewFile();
i.putExtra(MediaStore.EXTRA_OUTPUT,
Uri.fromFile(capturefile));//将拍摄的照片信息存到capturefile中

} catch (IOException e) {
// TODO Auto-generated catch block

e.printStackTrace();
}

startActivityForResult(i, PHOTO_WITH_CAMERA);// 用户点击了从照相机获取

} else {
showToast("没有SD卡");
}
break;

}
case 1:// 从相册中去获取

Intent intent = new Intent();
/* 开启Pictures画面Type设定为image */
intent.setType("image/*");
/* 使用Intent.ACTION_GET_CONTENT这个Action */
intent.setAction(Intent.ACTION_GET_CONTENT);
/* 取得相片后返回本画面 */
startActivityForResult(intent, PHOTO_WITH_DATA);
break;
}
}
});
builder.create().show();
}

final Context dialogContext = new ContextThemeWrapper(context,
android.R.style.Theme_Light);
String[] choices;
choices = new String[2];
choices[0] = "相机拍摄"; // 拍照
choices[1] = "本地相册"; // 从相册中选择
final ListAdapter adapter = new ArrayAdapter<String>(dialogContext,
android.R.layout.simple_list_item_1, choices);

final AlertDialog.Builder builder = new AlertDialog.Builder(
dialogContext);
builder.setTitle("添加图片");
builder.setSingleChoiceItems(adapter, -1,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
switch (which) {
case 0: {
String status = Environment
.getExternalStorageState();
if (status.equals(Environment.MEDIA_MOUNTED)) {// 判断是否有SD卡
Intent i = new Intent(
MediaStore.ACTION_IMAGE_CAPTURE);
capturefile = new File(PHOTO_DIR,
getPhotoFileName());
try {
capturefile.createNewFile();
i.putExtra(MediaStore.EXTRA_OUTPUT,
Uri.fromFile(capturefile));//将拍摄的照片信息存到capturefile中
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

startActivityForResult(i, PHOTO_WITH_CAMERA);// 用户点击了从照相机获取
} else {
showToast("没有SD卡");
}
break;

}
case 1:// 从相册中去获取
Intent intent = new Intent();
/* 开启Pictures画面Type设定为image */
intent.setType("image/*");
/* 使用Intent.ACTION_GET_CONTENT这个Action */
intent.setAction(Intent.ACTION_GET_CONTENT);
/* 取得相片后返回本画面 */
startActivityForResult(intent, PHOTO_WITH_DATA);
break;
}
}
});
builder.create().show();
}


Java代码







/*
* 通过相机回传图片的文件名
*/
private String getPhotoFileName() {
Date date = new Date(System.currentTimeMillis());
SimpleDateFormat dateFormat = new SimpleDateFormat(
"'IMG'_yyyyMMdd_HHmmss");
return dateFormat.format(date) + ".jpg";
}

/*
* 通过相机回传图片的文件名
*/
private String getPhotoFileName() {
Date date = new Date(System.currentTimeMillis());
SimpleDateFormat dateFormat = new SimpleDateFormat(
"'IMG'_yyyyMMdd_HHmmss");
return dateFormat.format(date) + ".jpg";
}


再来看OnActivityResult

Java代码







/*
* 选择图片的回传处理
*/
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

File file = null;
Bitmap pic = null;
if (resultCode == RESULT_OK) {
switch (requestCode) {
case PHOTO_WITH_CAMERA://获取拍摄的文件

picPath = capturefile.getAbsolutePath();
System.out.println(picPath);
file = new File(picPath);
pic = decodeFile(file);
thumbimage.setImageBitmap(pic);
System.out.println("++++++相机+++++");
break;

case PHOTO_WITH_DATA://获取从图库选择的文件

Uri uri = data.getData();
String scheme = uri.getScheme();
if (scheme.equalsIgnoreCase("file")) {
picPath = uri.getPath();
System.out.println(picPath);
file = new File(picPath);
pic = decodeFile(file);
thumbimage.setImageBitmap(pic);
} else if (scheme.equalsIgnoreCase("content")) {
Cursor cursor = getContentResolver().query(uri, null, null,
null, null);
cursor.moveToFirst();
picPath = cursor.getString(1);
file = new File(picPath);
pic = decodeFile(file);
thumbimage.setImageBitmap(pic);
}
break;
}

}
super.onActivityResult(requestCode, resultCode, data);
}

/*
* 选择图片的回传处理
*/
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
File file = null;
Bitmap pic = null;
if (resultCode == RESULT_OK) {
switch (requestCode) {
case PHOTO_WITH_CAMERA://获取拍摄的文件
picPath = capturefile.getAbsolutePath();
System.out.println(picPath);
file = new File(picPath);
pic = decodeFile(file);
thumbimage.setImageBitmap(pic);
System.out.println("++++++相机+++++");
break;

case PHOTO_WITH_DATA://获取从图库选择的文件
Uri uri = data.getData();
String scheme = uri.getScheme();
if (scheme.equalsIgnoreCase("file")) {
picPath = uri.getPath();
System.out.println(picPath);
file = new File(picPath);
pic = decodeFile(file);
thumbimage.setImageBitmap(pic);
} else if (scheme.equalsIgnoreCase("content")) {
Cursor cursor = getContentResolver().query(uri, null, null,
null, null);
cursor.moveToFirst();
picPath = cursor.getString(1);
file = new File(picPath);
pic = decodeFile(file);
thumbimage.setImageBitmap(pic);
}
break;
}

}
super.onActivityResult(requestCode, resultCode, data);
}

这里需要注意的是,从Gallery返回的内容,分为了两种情况。在模拟器上,我们可以发现返回的内容模式为"content”而从某些手机的操作例如MIUI,返回的scheme为"file"。同样,在MIUI上返回的照相内容依旧为file,但是可以通过通用方法,将照相的信息写入到我们制定的文件当中。也就是上面代码中的这两句

Java代码







Intent i = new Intent(
MediaStore.ACTION_IMAGE_CAPTURE);
capturefile = new File(PHOTO_DIR,
getPhotoFileName());
try {
capturefile.createNewFile();
i.putExtra(MediaStore.EXTRA_OUTPUT,
Uri.fromFile(capturefile));//将拍摄的照片信息存到capturefile中

} catch (IOException e) {
// TODO Auto-generated catch block

e.printStackTrace();
}

Intent i = new Intent(
MediaStore.ACTION_IMAGE_CAPTURE);
capturefile = new File(PHOTO_DIR,
getPhotoFileName());
try {
capturefile.createNewFile();
i.putExtra(MediaStore.EXTRA_OUTPUT,
Uri.fromFile(capturefile));//将拍摄的照片信息存到capturefile中
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}


在之前的文章中,我们为发送微博页面设计了一个ImageView用来显示选取的照片。但是我们发现,如果不对返回的照片做处理,那么在第二次选择照片的时候系统会抛出内存溢出的错误。网上对这个问题的解释是,android只为每个程序分配8M的缓存,所以图片不经过压缩就会抛出异常。那么我们把图片压缩之后再显示在ImageView当中,压缩方法如下:

Java代码







/*
* 压缩图片,避免内存不足报错
*/
private Bitmap decodeFile(File f) {
Bitmap b = null;
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;

FileInputStream fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();

int scale = 1;
if (o.outHeight > 100 || o.outWidth > 100) {

scale = (int) Math.pow(
2,
(int) Math.round(Math.log(100 / (double) Math.max(
o.outHeight, o.outWidth)) / Math.log(0.5)));
}

// Decode with inSampleSize

BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
return b;
}

/*
* 压缩图片,避免内存不足报错
*/
private Bitmap decodeFile(File f) {
Bitmap b = null;
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;

FileInputStream fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();

int scale = 1;
if (o.outHeight > 100 || o.outWidth > 100) {
scale = (int) Math.pow(
2,
(int) Math.round(Math.log(100 / (double) Math.max(
o.outHeight, o.outWidth)) / Math.log(0.5)));
}

// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
return b;
}


至此,我们完成了对图片的选择,下一篇文章会通过新浪指定的方法,实现将图片上传到微博,也就是发送一条带图片的微博。

转自:/article/4326187.html
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