Android: 将内部存储中的图像保存到 SharedPreferences 并显示
Android: Save image from Internal storage in SharedPreferences and display it
我正在尝试从我的 phone 加载图像并将其应用到 ImageView
。当我重新打开应用程序时,我需要这张图片保存在 ImageView
.
我正在尝试使用共享偏好来做类似的事情。但是我收到以下日志错误:
Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'android.content.SharedPreferences$Editor android.content.SharedPreferences$Editor.putString(java.lang.String, java.lang.String)' on a null object reference
private static final int PICK_IMAGE = 100;
static SharedPreferences sharedPref;
static SharedPreferences.Editor editor;
private static final String PREFS_NAME = "preferenceName";
Uri imageUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
PROFILE_IMG = (ImageView)findViewById(R.id.profile_image);
PHOTObutton = (Button)findViewById(R.id.photo_btn);
// Get from the SharedPreferences
sharedPref = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
String imageUriString = sharedPref.getString("imageURI", null);
Uri imageUri = Uri.parse(imageUriString);
PROFILE_IMG.setImageURI(imageUri);
//open gallery-- select profile photo
PHOTObutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
openGallery();
}
});
}
private void openGallery() {
Intent gallery = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.INTERNAL_CONTENT_URI);
startActivityForResult(gallery, PICK_IMAGE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == PICK_IMAGE){
imageUri = data.getData();
sharedPref = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
editor.putString("imageURI", imageUri.toString());
editor.commit();
PROFILE_IMG.setImageURI(imageUri);
}
}
我做错了什么?
您忘记初始化编辑器将其添加到您的活动结果中
editor=sharedPref.edit()
editor.putString("imageURI", imageUri.toString());
editor.commit();
这个错误是因为你的编辑器是空的。试试这个
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == PICK_IMAGE){
imageUri = data.getData();
SharedPreferences.Editor editor = getSharedPreferences(PREFS_NAME, MODE_PRIVATE).edit();
editor.putString("imageURI", imageUri.toString());
editor.commit();
PROFILE_IMG.setImageURI(imageUri);
}
}
我正在尝试从我的 phone 加载图像并将其应用到 ImageView
。当我重新打开应用程序时,我需要这张图片保存在 ImageView
.
我正在尝试使用共享偏好来做类似的事情。但是我收到以下日志错误:
Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'android.content.SharedPreferences$Editor android.content.SharedPreferences$Editor.putString(java.lang.String, java.lang.String)' on a null object reference
private static final int PICK_IMAGE = 100;
static SharedPreferences sharedPref;
static SharedPreferences.Editor editor;
private static final String PREFS_NAME = "preferenceName";
Uri imageUri;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
PROFILE_IMG = (ImageView)findViewById(R.id.profile_image);
PHOTObutton = (Button)findViewById(R.id.photo_btn);
// Get from the SharedPreferences
sharedPref = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
String imageUriString = sharedPref.getString("imageURI", null);
Uri imageUri = Uri.parse(imageUriString);
PROFILE_IMG.setImageURI(imageUri);
//open gallery-- select profile photo
PHOTObutton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
openGallery();
}
});
}
private void openGallery() {
Intent gallery = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.INTERNAL_CONTENT_URI);
startActivityForResult(gallery, PICK_IMAGE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == PICK_IMAGE){
imageUri = data.getData();
sharedPref = getApplicationContext().getSharedPreferences(PREFS_NAME, 0);
editor.putString("imageURI", imageUri.toString());
editor.commit();
PROFILE_IMG.setImageURI(imageUri);
}
}
我做错了什么?
您忘记初始化编辑器将其添加到您的活动结果中
editor=sharedPref.edit()
editor.putString("imageURI", imageUri.toString());
editor.commit();
这个错误是因为你的编辑器是空的。试试这个
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK && requestCode == PICK_IMAGE){
imageUri = data.getData();
SharedPreferences.Editor editor = getSharedPreferences(PREFS_NAME, MODE_PRIVATE).edit();
editor.putString("imageURI", imageUri.toString());
editor.commit();
PROFILE_IMG.setImageURI(imageUri);
}
}