Android 从库中拾取图像并设置为imageview
我正在尝试从gallery中选择图像并将其设置为imageviewAndroid 从库中拾取图像并设置为imageview,android,bitmap,cursor,gallery,Android,Bitmap,Cursor,Gallery,我正在尝试从gallery中选择图像并将其设置为imageview @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); try { // When an Image is picked if (requestCod
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
try {
// When an Image is picked
if (requestCode == RESULT_LOAD_IMG && resultCode == RESULT_OK
&& null != data) {
Log.e("1","1");
// Get the Image from data
Uri selectedImage = data.getData();
Log.e("2","2");
String[] filePathColumn = { MediaStore.Images.Media.DATA };
Log.e("3","3");
// Get the cursor
Cursor cursor = getContentResolver().query(selectedImage,
filePathColumn, null, null, null);
Log.e("4","4");
// Move to first row
cursor.moveToFirst();
Log.e("5", "5");
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
Log.e("6","6");
imgDecodableString = cursor.getString(columnIndex);
Log.e("7","7");
cursor.close();
ImageView imgView = (ImageView) findViewById(R.id.imgView);
Log.e("8","8");
// Set the Image in ImageView after decoding the String
imgView.setImageBitmap(BitmapFactory
.decodeFile(imgDecodableString));
} else {
Toast.makeText(this, "You haven't picked Image",
Toast.LENGTH_LONG).show();
}
} catch (Exception e) {
Toast.makeText(this, "Something went wrong", Toast.LENGTH_LONG)
.show();
}
}
private static int RESULT_LOAD_IMAGE = 1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button buttonLoadImage = (Button) findViewById(R.id.buttonLoadPicture);
buttonLoadImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent i = new Intent(
Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(i, RESULT_LOAD_IMAGE);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
Uri selectedImage = data.getData();
String[] filePathColumn = { MediaStore.Images.Media.DATA };
Cursor cursor = getContentResolver().query(selectedImage,
filePathColumn, null, null, null);
cursor.moveToFirst();
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
String picturePath = cursor.getString(columnIndex);
cursor.close();
ImageView imageView = (ImageView) findViewById(R.id.imgView);
imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));
}
}
}
这是我用来挑选画廊图片的代码，然后将其显示到
ImageViewprivate static final int GALLERY_PHOTO = 111;
private void pickGalleryImage() {
Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
intent.setType("image/*");
startActivityForResult(chooserIntent, GALLERY_PHOTO);
}
onActivityResult（）mContext活动的上下文。如果Activity
名称为MainActivity
，则可以使用MainActivity。此
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == GALLERY_PHOTO && resultCode == Activity.RESULT_OK) {
if (data.getData() != null) {
String filePath = GetFilePathFromDevice.getPath(mContext, data.getData());
Bitmap bm = BitmapFactory.decodeFile(filePath);
imgView.setImageBitmap(bm);
}
}
}
下面是onActivityResult（）
方法中使用的GetFilePathFromDevice
类，用于从库中获取所选图像的文件路径
public final class GetFilePathFromDevice {
/**
* Get file path from URI
*
* @param context context of Activity
* @param uri uri of file
* @return path of given URI
*/
public static String getPath(final Context context, final Uri uri) {
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id=?";
final String[] selectionArgs = new String[]{split[1]};
return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = {column};
try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
if (cursor != null && cursor.moveToFirst()) {
final int index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
public static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}
}
我希望这对您有所帮助。您是否添加了读取外部存储的权限？在catch块中打印stacktrace并将其发布到此处。我将这两个权限放在活动“”之前，这是catch异常“E/E:java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法”android.content.ContentResolver android.content.Context.getContentResolver（）“光标查询行中存在相同问题。此错误”java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“android.content.Context.getContentResolver（）”“我也尝试了这个，放置了try catch，它给出了这个异常”android.content.Context.getContentResolver android.content（）“ActivityResult中的'mContext'是什么，您初始化了吗？活动的名称是什么？然后尝试MainActivity。这代替了mContextnow，它给出了另一个异常，在空对象引用上尝试调用虚拟方法'void android.widget.ImageView.setImageBitmap（android.graphics.Bitmap）'”